java.lang

Class String

• • java.lang.String

• All Implemented Interfaces:

  ,  ,  < >

  ---

  
  

  public final class String extends  implements ,<>, 

  The 

  String class 

  represents(代表) character strings. All string 

  literals(字面值) in Java programs, 

  such as(比如) 

  "abc", are implemented(实现) as 

  instances(实例) of this class.

  Strings are constant(常量); their values cannot be changed after they are created. String buffers support(支持) mutable strings(可变字符串). Because String objects are immutable(不可变的) they can be shared(共享). For example:

  String str = "abc";

  is equivalent to(相当于):

  char data[] = {'a', 'b', 'c'}; String str = new String(data);

  Here are some more examples of how strings can be used:

  System.out.println("abc"); String cde = "cde"; System.out.println("abc" + cde); String c = "abc".substring(2,3); String d = cde.substring(1, 2);

  The class String includes methods for examining(检查) individual characters(单个字符串) of the sequence(序列), for comparing(比较) strings, for searchin(搜索) strings, for extracting(提取) substrings(子字符串), and for creating a copy of a string with all characters translated to uppercase or to lowercase. Case mapping(大小写映射) is based on the Unicode Standard version specified by the  class.

  The Java language provides special support for the string concatenation（串联）operator(操作符) ( + ), and for conversion of other objects to strings. String concatenation is implemented through(通过) the StringBuilder(or StringBuffer) class and its append method. String conversions are implemented through the methodtoString, defined by Object and inherited(继承) by all classes in Java. For additional(额外的) information on string concatenation and conversion, see Gosling, Joy, and Steele, The Java Language Specification.

  Unless otherwise noted（除非另外说明）, passing(传入) a null argument to a constructor(构造) or method in this class will cause a  to be thrown.

  A String represents a string in the UTF-16 format in which supplementary charactersare represented by surrogate pairs (see the section  in the Character class for more information). Index valuesrefer(指) to char code units, so a supplementary character(补充的字符) uses twopositions(位置) in a String.

  The String class provides methods for dealing with(处理) Unicode code points (i.e., characters), in addition(除...之外) to those for dealing with Unicode code units (i.e., char values).

  Since:

  JDK1.0

  See Also:

  ,  ,  ,  , 

• • Field Summary

    Fields

    Modifier and Type	Field and Description
    static<>	A Comparator that orders  String objects as by compareToIgnoreCase.
  • Constructor Summary

    Constructor and Description

    ()

    Initializes a newly created 

    String object so that it represents an empty character sequence.
    (byte[] bytes)

    Constructs a new 

    String by decoding the specified array of bytes using the platform's default charset.
    (byte[] bytes,  charset)

    Constructs a new 

    String by decoding the specified array of bytes using the specified  .
    (byte[] ascii, int hibyte)

    Deprecated.

    This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the String constructors that take a, charset name, or that use the platform's default charset.
    (byte[] bytes, int offset, int length)

    Constructs a new 

    String by decoding the specified subarray of bytes using the platform's default charset.
    (byte[] bytes, int offset, int length,  charset)

    Constructs a new 

    String by decoding the specified subarray of bytes using the specified  .
    (byte[] ascii, int hibyte, int offset, int count)

    Deprecated.

    This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the String constructors that take a, charset name, or that use the platform's default charset.
    (byte[] bytes, int offset, int length,  charsetName)

    Constructs a new 

    String by decoding the specified subarray of bytes using the specified charset.
    (byte[] bytes,  charsetName)

    Constructs a new 

    String by decoding the specified array of bytes using the specified  .
    (char[] value)

    Allocates a new 

    String so that it represents the sequence of characters currently contained in the character array argument.
    (char[] value, int offset, int count)

    Allocates a new 

    String that contains characters from a subarray of the character array argument.
    (int[] codePoints, int offset, int count)

    Allocates a new 

    String that contains characters from a subarray of the  array argument.
    ( original)

    Initializes a newly created 

    String object so that it represents the same sequence of characters as the argument; in other words, the newly created string is a copy of the argument string.
    ( buffer)

    Allocates a new string that contains the sequence of characters currently contained in the string buffer argument.
    ( builder)

    Allocates a new string that contains the sequence of characters currently contained in the string builder argument.
  • Method Summary

    Methods

    Modifier and Type	Method and Description
    char	(int index) Returns the  char value at the specified index.
    int	(int index) Returns the character (Unicode code point) at the specified index.
    int	(int index) Returns the character (Unicode code point) before the specified index.
    int	(int beginIndex, int endIndex) Returns the number of Unicode code points in the specified text range of this  String.
    int	( anotherString) Compares two strings lexicographically.
    int	( str) Compares two strings lexicographically, ignoring case differences.
    	( str) Concatenates the specified string to the end of this string.
    boolean	( s) Returns true if and only if this string contains the specified sequence of char values.
    boolean	( cs) Compares this string to the specified  CharSequence.
    boolean	( sb) Compares this string to the specified  StringBuffer.
    static	(char[] data) Returns a String that represents the character sequence in the array specified.
    static	(char[] data, int offset, int count) Returns a String that represents the character sequence in the array specified.
    boolean	( suffix) Tests if this string ends with the specified suffix.
    boolean	( anObject) Compares this string to the specified object.
    boolean	( anotherString) Compares this  String to another  String, ignoring case considerations.
    static	( l,  format, ... args) Returns a formatted string using the specified locale, format string, and arguments.
    static	( format, ... args) Returns a formatted string using the specified format string and arguments.
    byte[]	() Encodes this  String into a sequence of bytes using the platform's default charset, storing the result into a new byte array.
    byte[]	( charset) Encodes this  String into a sequence of bytes using the given , storing the result into a new byte array.
    void	(int srcBegin, int srcEnd, byte[] dst, int dstBegin) Deprecated. This method does not properly convert characters into bytes. As of JDK 1.1, the preferred way to do this is via the method, which uses the platform's default charset.
    byte[]	( charsetName) Encodes this  String into a sequence of bytes using the named charset, storing the result into a new byte array.
    void	(int srcBegin, int srcEnd, char[] dst, int dstBegin) Copies characters from this string into the destination character array.
    int	() Returns a hash code for this string.
    int	(int ch) Returns the index within this string of the first occurrence of the specified character.
    int	(int ch, int fromIndex) Returns the index within this string of the first occurrence of the specified character, starting the search at the specified index.
    int	( str) Returns the index within this string of the first occurrence of the specified substring.
    int	( str, int fromIndex) Returns the index within this string of the first occurrence of the specified substring, starting at the specified index.
    	() Returns a canonical representation for the string object.
    boolean	() Returns  true if, and only if,   is  0.
    int	(int ch) Returns the index within this string of the last occurrence of the specified character.
    int	(int ch, int fromIndex) Returns the index within this string of the last occurrence of the specified character, searching backward starting at the specified index.
    int	( str) Returns the index within this string of the last occurrence of the specified substring.
    int	( str, int fromIndex) Returns the index within this string of the last occurrence of the specified substring, searching backward starting at the specified index.
    int	() Returns the length of this string.
    boolean	( regex) Tells whether or not this string matches the given  .
    int	(int index, int codePointOffset) Returns the index within this  String that is offset from the given  index by  codePointOffset code points.
    boolean	(boolean ignoreCase, int toffset,  other, int ooffset, int len) Tests if two string regions are equal.
    boolean	(int toffset,  other, int ooffset, int len) Tests if two string regions are equal.
    	(char oldChar, char newChar) Returns a new string resulting from replacing all occurrences of oldChar in this string with  newChar.
    	( target,  replacement) Replaces each substring of this string that matches the literal target sequence with the specified literal replacement sequence.
    	( regex,  replacement) Replaces each substring of this string that matches the given  with the given replacement.
    	( regex,  replacement) Replaces the first substring of this string that matches the given   with the given replacement.
    []	( regex) Splits this string around matches of the given  .
    []	( regex, int limit) Splits this string around matches of the given  .
    boolean	( prefix) Tests if this string starts with the specified prefix.
    boolean	( prefix, int toffset) Tests if the substring of this string beginning at the specified index starts with the specified prefix.
    	(int beginIndex, int endIndex) Returns a new character sequence that is a subsequence of this sequence.
    	(int beginIndex) Returns a new string that is a substring of this string.
    	(int beginIndex, int endIndex) Returns a new string that is a substring of this string.
    char[]	() Converts this string to a new character array.
    	() Converts all of the characters in this  String to lower case using the rules of the default locale.
    	( locale) Converts all of the characters in this  String to lower case using the rules of the given  Locale.
    	() This object (which is already a string!) is itself returned.
    	() Converts all of the characters in this  String to upper case using the rules of the default locale.
    	( locale) Converts all of the characters in this  String to upper case using the rules of the given  Locale.
    	() Returns a copy of the string, with leading and trailing whitespace omitted.
    static	(boolean b) Returns the string representation of the  boolean argument.
    static	(char c) Returns the string representation of the  char argument.
    static	(char[] data) Returns the string representation of the  char array argument.
    static	(char[] data, int offset, int count) Returns the string representation of a specific subarray of the char array argument.
    static	(double d) Returns the string representation of the  double argument.
    static	(float f) Returns the string representation of the  float argument.
    static	(int i) Returns the string representation of the  int argument.
    static	(long l) Returns the string representation of the  long argument.
    static	( obj) Returns the string representation of the  Object argument.

    • Methods inherited from class java.lang.

      , , , , , , , 

• • Field Detail

    • CASE_INSENSITIVE_ORDER

      public static final <> CASE_INSENSITIVE_ORDER

      A Comparator that orders 

      String objects as by 

      compareToIgnoreCase. This comparator is serializable.

      Note that this Comparator does not take locale into account, and will result in an unsatisfactory ordering for certain locales. The java.text package provides Collators to allow locale-sensitive ordering.

      Since:

      1.2

      See Also:
  • Constructor Detail

    • String

      public String()

      Initializes a newly created 

      String object so that it represents an empty character sequence. Note that use of this constructor is unnecessary since Strings are immutable.
    • String

      public String( original)

      Initializes a newly created 

      String object so that it represents the same sequence of characters as the argument; in other words, the newly created string is a copy of the argument string. Unless an explicit copy of

      original is needed, use of this constructor is unnecessary since Strings are immutable.

      Parameters:

      original - A 

      String
    • String

      public String(char[] value)

      Allocates a new 

      String so that it represents the sequence of characters currently contained in the character array argument. The contents of the character array are copied; subsequent modification of the character array does not affect the newly created string.

      Parameters:

      value - The initial value of the string
    • String

      public String(char[] value, int offset, int count)

      Allocates a new 

      String that contains characters from a subarray of the character array argument. The 

      offset argument is the index of the first character of the subarray and the 

      count argument specifies the length of the subarray. The contents of the subarray are copied; subsequent modification of the character array does not affect the newly created string.

      Parameters:

      value - Array that is the source of characters

      offset - The initial offset

      count - The length

      Throws:

       - If the 

      offset and 

      count arguments index characters outside the bounds of the 

      value array
    • String

      public String(int[] codePoints, int offset, int count)

      Allocates a new 

      String that contains characters from a subarray of the  array argument. The 

      offset argument is the index of the first code point of the subarray and the 

      count argument specifies the length of the subarray. The contents of the subarray are converted to

      chars; subsequent modification of the 

      int array does not affect the newly created string.

      Parameters:

      codePoints - Array that is the source of Unicode code points

      offset - The initial offset

      count - The length

      Throws:

       - If any invalid Unicode code point is found in 

      codePoints

       - If the 

      offset and 

      count arguments index characters outside the bounds of the 

      codePoints array

      Since:

      1.5
    • String

       public String(byte[] ascii, int hibyte, int offset, int count)

      Deprecated. 

      This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the Stringconstructors that take a , charset name, or that use the platform's default charset.
      Allocates a new 

      String constructed from a subarray of an array of 8-bit integer values.

      The offset argument is the index of the first byte of the subarray, and the count argument specifies the length of the subarray.

      Each byte in the subarray is converted to a char as specified in the method above.

      Parameters:

      ascii - The bytes to be converted to characters

      hibyte - The top 8 bits of each 16-bit Unicode code unit

      offset - The initial offset

      count - The length

      Throws:

       - If the 

      offset or 

      count argument is invalid

      See Also:

      ,  , ,  ,  ,  , 
    • String

       public String(byte[] ascii, int hibyte)

      Deprecated. 

      This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the Stringconstructors that take a , charset name, or that use the platform's default charset.
      Allocates a new 

      String containing characters constructed from an array of 8-bit integer values. Each character 

      cin the resulting string is constructed from the corresponding component 

      b in the byte array such that:

      c == (char)(((hibyte & 0xff) << 8) | (b & 0xff))

      Parameters:

      ascii - The bytes to be converted to characters

      hibyte - The top 8 bits of each 16-bit Unicode code unit

      See Also:

      ,  ,  ,  ,  ,
    • String

      public String(byte[] bytes, int offset, int length,  charsetName) throws 

      Constructs a new 

      String by decoding the specified subarray of bytes using the specified charset. The length of the new 

      String is a function of the charset, and hence may not be equal to the length of the subarray.

      The behavior of this constructor when the given bytes are not valid in the given charset is unspecified. The  class should be used when more control over the decoding process is required.

      Parameters:

      bytes - The bytes to be decoded into characters

      offset - The index of the first byte to decode

      length - The number of bytes to decode

      charsetName - The name of a supported 

      Throws:

       - If the named charset is not supported

       - If the 

      offset and 

      length arguments index characters outside the bounds of the 

      bytes array

      Since:

      JDK1.1
    • String

      public String(byte[] bytes, int offset, int length,  charset)

      Constructs a new 

      String by decoding the specified subarray of bytes using the specified  . The length of the new 

      String is a function of the charset, and hence may not be equal to the length of the subarray.

      This method always replaces malformed-input and unmappable-character sequences with this charset's default replacement string. The class should be used when more control over the decoding process is required.

      Parameters:

      bytes - The bytes to be decoded into characters

      offset - The index of the first byte to decode

      length - The number of bytes to decode

      charset - The   to be used to decode the 

      bytes

      Throws:

       - If the 

      offset and 

      length arguments index characters outside the bounds of the 

      bytes array

      Since:

      1.6
    • String

      public String(byte[] bytes,  charsetName) throws

      Constructs a new 

      String by decoding the specified array of bytes using the specified  . The length of the new 

      String is a function of the charset, and hence may not be equal to the length of the byte array.

      The behavior of this constructor when the given bytes are not valid in the given charset is unspecified. The  class should be used when more control over the decoding process is required.

      Parameters:

      bytes - The bytes to be decoded into characters

      charsetName - The name of a supported 

      Throws:

       - If the named charset is not supported

      Since:

      JDK1.1
    • String

      public String(byte[] bytes,  charset)

      Constructs a new 

      String by decoding the specified array of bytes using the specified  . The length of the new 

      String is a function of the charset, and hence may not be equal to the length of the byte array.

      This method always replaces malformed-input and unmappable-character sequences with this charset's default replacement string. The class should be used when more control over the decoding process is required.

      Parameters:

      bytes - The bytes to be decoded into characters

      charset - The   to be used to decode the 

      bytes

      Since:

      1.6
    • String

      public String(byte[] bytes, int offset, int length)

      Constructs a new 

      String by decoding the specified subarray of bytes using the platform's default charset. The length of the new 

      String is a function of the charset, and hence may not be equal to the length of the subarray.

      The behavior of this constructor when the given bytes are not valid in the default charset is unspecified. The  class should be used when more control over the decoding process is required.

      Parameters:

      bytes - The bytes to be decoded into characters

      offset - The index of the first byte to decode

      length - The number of bytes to decode

      Throws:

       - If the 

      offset and the 

      length arguments index characters outside the bounds of the 

      bytes array

      Since:

      JDK1.1
    • String

      public String(byte[] bytes)

      Constructs a new 

      String by decoding the specified array of bytes using the platform's default charset. The length of the new 

      String is a function of the charset, and hence may not be equal to the length of the byte array.

      The behavior of this constructor when the given bytes are not valid in the default charset is unspecified. The  class should be used when more control over the decoding process is required.

      Parameters:

      bytes - The bytes to be decoded into characters

      Since:

      JDK1.1
    • String

      public String( buffer)

      Allocates a new string that contains the sequence of characters currently contained in the string buffer argument. The contents of the string buffer are copied; subsequent modification of the string buffer does not affect the newly created string.

      Parameters:

      buffer - A 

      StringBuffer
    • String

      public String( builder)

      Allocates a new string that contains the sequence of characters currently contained in the string builder argument. The contents of the string builder are copied; subsequent modification of the string builder does not affect the newly created string.

      This constructor is provided to ease migration to StringBuilder. Obtaining a string from a string builder via the toString method is likely to run faster and is generally preferred.

      Parameters:

      builder - A 

      StringBuilder

      Since:

      1.5
  • Method Detail

    • length

      public int length()

      Returns the length of this string. The length is equal to the number of  in the string.

      Specified by:

       in interface 

      Returns:

      the length of the sequence of characters represented by this object.
    • isEmpty

      public boolean isEmpty()

      Returns 

      true if, and only if,   is 

      0.

      Returns:

      true if   is 

      0, otherwise 

      false

      Since:

      1.6
    • charAt

      public char charAt(int index)

      Returns the 

      char value at the specified index. An index ranges from 

      0 to

      length() - 1. The first 

      char value of the sequence is at index 

      0, the next at index 

      1, and so on, as for array indexing.

      If the char value specified by the index is a , the surrogate value is returned.

      Specified by:

       in interface 

      Parameters:

      index - the index of the 

      char value.

      Returns:

      the 

      char value at the specified index of this string. The first 

      charvalue is at index 

      0.

      Throws:

       - if the 

      index argument is negative or not less than the length of this string.
    • codePointAt

      public int codePointAt(int index)

      Returns the character (Unicode code point) at the specified index. The index refers to 

      char values (Unicode code units) and ranges from 

      0 to  

      - 1.

      If the char value specified at the given index is in the high-surrogate range, the following index is less than the length of this String, and the char value at the following index is in the low-surrogate range, then the supplementary code point corresponding to this surrogate pair is returned. Otherwise, the char value at the given index is returned.

      Parameters:

      index - the index to the 

      char values

      Returns:

      the code point value of the character at the 

      index

      Throws:

       - if the 

      index argument is negative or not less than the length of this string.

      Since:

      1.5
    • codePointBefore

      public int codePointBefore(int index)

      Returns the character (Unicode code point) before the specified index. The index refers to 

      char values (Unicode code units) and ranges from 

      1 to .

      If the char value at (index - 1) is in the low-surrogate range, (index - 2) is not negative, and the char value at (index - 2) is in the high-surrogate range, then the supplementary code point value of the surrogate pair is returned. If the char value at index - 1 is an unpaired low-surrogate or a high-surrogate, the surrogate value is returned.

      Parameters:

      index - the index following the code point that should be returned

      Returns:

      the Unicode code point value before the given index.

      Throws:

       - if the 

      index argument is less than 1 or greater than the length of this string.

      Since:

      1.5
    • codePointCount

      public int codePointCount(int beginIndex, int endIndex)

      Returns the number of Unicode code points in the specified text range of this 

      String. The text range begins at the specified 

      beginIndex and extends to the 

      char at index 

      endIndex - 1. Thus the length (in 

      chars) of the text range is 

      endIndex-beginIndex. Unpaired surrogates within the text range count as one code point each.

      Parameters:

      beginIndex - the index to the first 

      char of the text range.

      endIndex - the index after the last 

      char of the text range.

      Returns:

      the number of Unicode code points in the specified text range

      Throws:

       - if the 

      beginIndex is negative, or

      endIndex is larger than the length of this 

      String, or 

      beginIndex is larger than 

      endIndex.

      Since:

      1.5
    • offsetByCodePoints

      public int offsetByCodePoints(int index, int codePointOffset)

      Returns the index within this 

      String that is offset from the given 

      indexby 

      codePointOffset code points. Unpaired surrogates within the text range given by 

      index and 

      codePointOffset count as one code point each.

      Parameters:

      index - the index to be offset

      codePointOffset - the offset in code points

      Returns:

      the index within this 

      String

      Throws:

       - if 

      index is negative or larger then the length of this 

      String, or if 

      codePointOffset is positive and the substring starting with 

      index has fewer than 

      codePointOffset code points, or if 

      codePointOffset is negative and the substring before

      index has fewer than the absolute value of 

      codePointOffset code points.

      Since:

      1.5
    • getChars

      public void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)

      Copies characters from this string into the destination character array.

      The first character to be copied is at index srcBegin; the last character to be copied is at index srcEnd-1 (thus the total number of characters to be copied is srcEnd-srcBegin). The characters are copied into the subarray of dst starting at index dstBegin and ending at index:

      dstbegin + (srcEnd-srcBegin) - 1

      Parameters:

      srcBegin - index of the first character in the string to copy.

      srcEnd - index after the last character in the string to copy.

      dst - the destination array.

      dstBegin - the start offset in the destination array.

      Throws:

       - If any of the following is true:

      • srcBegin is negative.
      • srcBegin is greater than srcEnd
      • srcEnd is greater than the length of this string
      • dstBegin is negative
      • dstBegin+(srcEnd-srcBegin) is larger than dst.length
    • getBytes

       public void getBytes(int srcBegin, int srcEnd, byte[] dst, int dstBegin)

      Deprecated. 

      This method does not properly convert characters into bytes. As of JDK 1.1, the preferred way to do this is via the  method, which uses the platform's default charset.
      Copies characters from this string into the destination byte array. Each byte receives the 8 low-order bits of the corresponding character. The eight high-order bits of each character are not copied and do not participate in the transfer in any way.

      The first character to be copied is at index srcBegin; the last character to be copied is at index srcEnd-1. The total number of characters to be copied is srcEnd-srcBegin. The characters, converted to bytes, are copied into the subarray of dst starting at index dstBegin and ending at index:

      dstbegin + (srcEnd-srcBegin) - 1

      Parameters:

      srcBegin - Index of the first character in the string to copy

      srcEnd - Index after the last character in the string to copy

      dst - The destination array

      dstBegin - The start offset in the destination array

      Throws:

       - If any of the following is true:

      • srcBegin is negative
      • srcBegin is greater than srcEnd
      • srcEnd is greater than the length of this String
      • dstBegin is negative
      • dstBegin+(srcEnd-srcBegin) is larger than dst.length
    • getBytes

      public byte[] getBytes( charsetName) throws

      Encodes this 

      String into a sequence of bytes using the named charset, storing the result into a new byte array.

      The behavior of this method when this string cannot be encoded in the given charset is unspecified. The  class should be used when more control over the encoding process is required.

      Parameters:

      charsetName - The name of a supported 

      Returns:

      The resultant byte array

      Throws:

       - If the named charset is not supported

      Since:

      JDK1.1
    • getBytes

      public byte[] getBytes( charset)

      Encodes this 

      String into a sequence of bytes using the given  , storing the result into a new byte array.

      This method always replaces malformed-input and unmappable-character sequences with this charset's default replacement byte array. The class should be used when more control over the encoding process is required.

      Parameters:

      charset - The   to be used to encode the 

      String

      Returns:

      The resultant byte array

      Since:

      1.6
    • getBytes

      public byte[] getBytes()

      Encodes this 

      String into a sequence of bytes using the platform's default charset, storing the result into a new byte array.

      The behavior of this method when this string cannot be encoded in the default charset is unspecified. The  class should be used when more control over the encoding process is required.

      Returns:

      The resultant byte array

      Since:

      JDK1.1
    • equals

      public boolean equals( anObject)

      Compares this string to the specified object. The result is 

      true if and only if the argument is not 

      null and is a 

      String object that represents the same sequence of characters as this object.

      Overrides:

       in class 

      Parameters:

      anObject - The object to compare this 

      String against

      Returns:

      true if the given object represents a 

      String equivalent to this string, 

      false otherwise

      See Also:

      , 
    • contentEquals

      public boolean contentEquals( sb)

      Compares this string to the specified 

      StringBuffer. The result is 

      true if and only if this 

      String represents the same sequence of characters as the specified 

      StringBuffer.

      Parameters:

      sb - The 

      StringBuffer to compare this 

      String against

      Returns:

      true if this 

      String represents the same sequence of characters as the specified 

      StringBuffer, 

      false otherwise

      Since:

      1.4
    • contentEquals

      public boolean contentEquals( cs)

      Compares this string to the specified 

      CharSequence. The result is 

      true if and only if this 

      String represents the same sequence of char values as the specified sequence.

      Parameters:

      cs - The sequence to compare this 

      String against

      Returns:

      true if this 

      String represents the same sequence of char values as the specified sequence, 

      false otherwise

      Since:

      1.5
    • equalsIgnoreCase

      public boolean equalsIgnoreCase( anotherString)

      Compares this 

      String to another 

      String, ignoring case considerations. Two strings are considered equal ignoring case if they are of the same length and corresponding characters in the two strings are equal ignoring case.

      Two characters c1 and c2 are considered the same ignoring case if at least one of the following is true:

      • The two characters are the same (as compared by the == operator)
      • Applying the method  to each character produces the same result
      • Applying the method  to each character produces the same result

      Parameters:

      anotherString - The 

      String to compare this 

      String against

      Returns:

      true if the argument is not 

      null and it represents an equivalent

      String ignoring case; 

      false otherwise

      See Also:
    • compareTo

      public int compareTo( anotherString)

      Compares two strings lexicographically. The comparison is based on the Unicode value of each character in the strings. The character sequence represented by this 

      String object is compared lexicographically to the character sequence represented by the argument string. The result is a negative integer if this 

      String object lexicographically precedes the argument string. The result is a positive integer if this 

      String object lexicographically follows the argument string. The result is zero if the strings are equal; 

      compareTo returns 

      0 exactly when the  method would return 

      true.

      This is the definition of lexicographic ordering. If two strings are different, then either they have different characters at some index that is a valid index for both strings, or their lengths are different, or both. If they have different characters at one or more index positions, let k be the smallest such index; then the string whose character at position k has the smaller value, as determined by using the < operator, lexicographically precedes the other string. In this case, compareToreturns the difference of the two character values at position k in the two string -- that is, the value:

      this.charAt(k)-anotherString.charAt(k)

      If there is no index position at which they differ, then the shorter string lexicographically precedes the longer string. In this case,

      compareTo returns the difference of the lengths of the strings -- that is, the value:

      this.length()-anotherString.length()

      Specified by:

       in interface 

      <>

      Parameters:

      anotherString - the 

      String to be compared.

      Returns:

      the value 

      0 if the argument string is equal to this string; a value less than 

      0 if this string is lexicographically less than the string argument; and a value greater than 

      0 if this string is lexicographically greater than the string argument.
    • compareToIgnoreCase

      public int compareToIgnoreCase( str)

      Compares two strings lexicographically, ignoring case differences. This method returns an integer whose sign is that of calling 

      compareTo with normalized versions of the strings where case differences have been eliminated by calling

      Character.toLowerCase(Character.toUpperCase(character)) on each character.

      Note that this method does not take locale into account, and will result in an unsatisfactory ordering for certain locales. The java.text package provides collators to allow locale-sensitive ordering.

      Parameters:

      str - the 

      String to be compared.

      Returns:

      a negative integer, zero, or a positive integer as the specified String is greater than, equal to, or less than this String, ignoring case considerations.

      Since:

      1.2

      See Also:
    • regionMatches

      public boolean regionMatches(int toffset,  other, int ooffset, int len)

      Tests if two string regions are equal.

      A substring of this String object is compared to a substring of the argument other. The result is true if these substrings represent identical character sequences. The substring of this String object to be compared begins at index toffset and has length len. The substring of other to be compared begins at index ooffset and has length len. The result is false if and only if at least one of the following is true:

      • toffset is negative.
      • ooffset is negative.
      • toffset+len is greater than the length of this String object.
      • ooffset+len is greater than the length of the other argument.
      • There is some nonnegative integer k less than len such that:this.charAt(toffset+k) != other.charAt(ooffset+k)

      Parameters:

      toffset - the starting offset of the subregion in this string.

      other - the string argument.

      ooffset - the starting offset of the subregion in the string argument.

      len - the number of characters to compare.

      Returns:

      true if the specified subregion of this string exactly matches the specified subregion of the string argument; 

      false otherwise.
    • regionMatches

      public boolean regionMatches(boolean ignoreCase, int toffset, other, int ooffset, int len)

      Tests if two string regions are equal.

      A substring of this String object is compared to a substring of the argument other. The result is true if these substrings represent character sequences that are the same, ignoring case if and only ifignoreCase is true. The substring of this String object to be compared begins at index toffset and has length len. The substring of other to be compared begins at index ooffset and has length len. The result is falseif and only if at least one of the following is true:

      • toffset is negative.
      • ooffset is negative.
      • toffset+len is greater than the length of this String object.
      • ooffset+len is greater than the length of the other argument.
      • ignoreCase is false and there is some nonnegative integer k less than len such that:

        this.charAt(toffset+k) != other.charAt(ooffset+k)

      • ignoreCase is true and there is some nonnegative integer k less thanlen such that:

        Character.toLowerCase(this.charAt(toffset+k)) != Character.toLowerCase(other.charAt(ooffset+k))

        and:

        Character.toUpperCase(this.charAt(toffset+k)) != Character.toUpperCase(other.charAt(ooffset+k))

      Parameters:

      ignoreCase - if 

      true, ignore case when comparing characters.

      toffset - the starting offset of the subregion in this string.

      other - the string argument.

      ooffset - the starting offset of the subregion in the string argument.

      len - the number of characters to compare.

      Returns:

      true if the specified subregion of this string matches the specified subregion of the string argument; 

      false otherwise. Whether the matching is exact or case insensitive depends on the 

      ignoreCaseargument.
    • startsWith

      public boolean startsWith( prefix, int toffset)

      Tests if the substring of this string beginning at the specified index starts with the specified prefix.

      Parameters:

      prefix - the prefix.

      toffset - where to begin looking in this string.

      Returns:

      true if the character sequence represented by the argument is a prefix of the substring of this object starting at index 

      toffset;

      false otherwise. The result is 

      false if 

      toffset is negative or greater than the length of this 

      String object; otherwise the result is the same as the result of the expression

      this.substring(toffset).startsWith(prefix)
    • startsWith

      public boolean startsWith( prefix)

      Tests if this string starts with the specified prefix.

      Parameters:

      prefix - the prefix.

      Returns:

      true if the character sequence represented by the argument is a prefix of the character sequence represented by this string; 

      falseotherwise. Note also that 

      true will be returned if the argument is an empty string or is equal to this 

      String object as determined by the   method.

      Since:

      1. 0
    • endsWith

      public boolean endsWith( suffix)

      Tests if this string ends with the specified suffix.

      Parameters:

      suffix - the suffix.

      Returns:

      true if the character sequence represented by the argument is a suffix of the character sequence represented by this object; 

      falseotherwise. Note that the result will be 

      true if the argument is the empty string or is equal to this 

      String object as determined by the  method.
    • hashCode

      public int hashCode()

      Returns a hash code for this string. The hash code for a 

      String object is computed as

      s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]

      using 

      int arithmetic, where 

      s[i] is the 

      ith character of the string, 

      n is the length of the string, and 

      ^ indicates exponentiation. (The hash value of the empty string is zero.)

      Overrides:

       in class 

      Returns:

      a hash code value for this object.

      See Also:

      ,
    • indexOf

      public int indexOf(int ch)

      Returns the index within this string of the first occurrence of the specified character. If a character with value 

      ch occurs in the character sequence represented by this 

      String object, then the index (in Unicode code units) of the first such occurrence is returned. For values of 

      ch in the range from 0 to 0xFFFF (inclusive), this is the smallest value 

      k such that:

      this.charAt(k) == ch

      is true. For other values of 

      ch, it is the smallest value 

      k such that:

      this.codePointAt(k) == ch

      is true. In either case, if no such character occurs in this string, then

      -1 is returned.

      Parameters:

      ch - a character (Unicode code point).

      Returns:

      the index of the first occurrence of the character in the character sequence represented by this object, or 

      -1 if the character does not occur.
    • indexOf

      public int indexOf(int ch, int fromIndex)

      Returns the index within this string of the first occurrence of the specified character, starting the search at the specified index.

      If a character with value ch occurs in the character sequence represented by this String object at an index no smaller than fromIndex, then the index of the first such occurrence is returned. For values of ch in the range from 0 to 0xFFFF (inclusive), this is the smallest value k such that:

      (this.charAt(k) == ch) && (k >= fromIndex)

      is true. For other values of 

      ch, it is the smallest value 

      k such that:

      (this.codePointAt(k) == ch) && (k >= fromIndex)

      is true. In either case, if no such character occurs in this string at or after position 

      fromIndex, then 

      -1 is returned.

      There is no restriction on the value of fromIndex. If it is negative, it has the same effect as if it were zero: this entire string may be searched. If it is greater than the length of this string, it has the same effect as if it were equal to the length of this string: -1 is returned.

      All indices are specified in char values (Unicode code units).

      Parameters:

      ch - a character (Unicode code point).

      fromIndex - the index to start the search from.

      Returns:

      the index of the first occurrence of the character in the character sequence represented by this object that is greater than or equal to

      fromIndex, or 

      -1 if the character does not occur.
    • lastIndexOf

      public int lastIndexOf(int ch)

      Returns the index within this string of the last occurrence of the specified character. For values of 

      ch in the range from 0 to 0xFFFF (inclusive), the index (in Unicode code units) returned is the largest value 

      k such that:

      this.charAt(k) == ch

      is true. For other values of 

      ch, it is the largest value 

      k such that:

      this.codePointAt(k) == ch

      is true. In either case, if no such character occurs in this string, then

      -1 is returned. The 

      String is searched backwards starting at the last character.

      Parameters:

      ch - a character (Unicode code point).

      Returns:

      the index of the last occurrence of the character in the character sequence represented by this object, or 

      -1 if the character does not occur.
    • lastIndexOf

      public int lastIndexOf(int ch, int fromIndex)

      Returns the index within this string of the last occurrence of the specified character, searching backward starting at the specified index. For values of 

      ch in the range from 0 to 0xFFFF (inclusive), the index returned is the largest value 

      k such that:

      (this.charAt(k) == ch) && (k <= fromIndex)

      is true. For other values of 

      ch, it is the largest value 

      k such that:

      (this.codePointAt(k) == ch) && (k <= fromIndex)

      is true. In either case, if no such character occurs in this string at or before position 

      fromIndex, then 

      -1 is returned.

      All indices are specified in char values (Unicode code units).

      Parameters:

      ch - a character (Unicode code point).

      fromIndex - the index to start the search from. There is no restriction on the value of 

      fromIndex. If it is greater than or equal to the length of this string, it has the same effect as if it were equal to one less than the length of this string: this entire string may be searched. If it is negative, it has the same effect as if it were -1: -1 is returned.

      Returns:

      the index of the last occurrence of the character in the character sequence represented by this object that is less than or equal to

      fromIndex, or 

      -1 if the character does not occur before that point.
    • indexOf

      public int indexOf( str)

      Returns the index within this string of the first occurrence of the specified substring.

      The returned index is the smallest value k for which:

      this.startsWith(str, k)

      If no such value of 

      k exists, then 

      -1 is returned.

      Parameters:

      str - the substring to search for.

      Returns:

      the index of the first occurrence of the specified substring, or 

      -1if there is no such occurrence.
    • indexOf

      public int indexOf( str, int fromIndex)

      Returns the index within this string of the first occurrence of the specified substring, starting at the specified index.

      The returned index is the smallest value k for which:

      k >= fromIndex && this.startsWith(str, k)

      If no such value of 

      k exists, then 

      -1 is returned.

      Parameters:

      str - the substring to search for.

      fromIndex - the index from which to start the search.

      Returns:

      the index of the first occurrence of the specified substring, starting at the specified index, or 

      -1 if there is no such occurrence.
    • lastIndexOf

      public int lastIndexOf( str)

      Returns the index within this string of the last occurrence of the specified substring. The last occurrence of the empty string "" is considered to occur at the index value 

      this.length().

      The returned index is the largest value k for which:

      this.startsWith(str, k)

      If no such value of 

      k exists, then 

      -1 is returned.

      Parameters:

      str - the substring to search for.

      Returns:

      the index of the last occurrence of the specified substring, or 

      -1if there is no such occurrence.
    • lastIndexOf

      public int lastIndexOf( str, int fromIndex)

      Returns the index within this string of the last occurrence of the specified substring, searching backward starting at the specified index.

      The returned index is the largest value k for which:

      k <= fromIndex && this.startsWith(str, k)

      If no such value of 

      k exists, then 

      -1 is returned.

      Parameters:

      str - the substring to search for.

      fromIndex - the index to start the search from.

      Returns:

      the index of the last occurrence of the specified substring, searching backward from the specified index, or 

      -1 if there is no such occurrence.
    • substring

      public  substring(int beginIndex)

      Returns a new string that is a substring of this string. The substring begins with the character at the specified index and extends to the end of this string.

      Examples:

      "unhappy".substring(2) returns "happy" "Harbison".substring(3) returns "bison" "emptiness".substring(9) returns "" (an empty string)

      Parameters:

      beginIndex - the beginning index, inclusive.

      Returns:

      the specified substring.

      Throws:

       - if 

      beginIndex is negative or larger than the length of this 

      String object.
    • substring

      public  substring(int beginIndex, int endIndex)

      Returns a new string that is a substring of this string. The substring begins at the specified 

      beginIndex and extends to the character at index

      endIndex - 1. Thus the length of the substring is 

      endIndex-beginIndex.

      Examples:

      "hamburger".substring(4, 8) returns "urge" "smiles".substring(1, 5) returns "mile"

      Parameters:

      beginIndex - the beginning index, inclusive.

      endIndex - the ending index, exclusive.

      Returns:

      the specified substring.

      Throws:

       - if the 

      beginIndex is negative, or

      endIndex is larger than the length of this 

      String object, or

      beginIndex is larger than 

      endIndex.
    • subSequence

      public  subSequence(int beginIndex, int endIndex)

      Returns a new character sequence that is a subsequence of this sequence.

      An invocation of this method of the form

      str.subSequence(begin, end)

      behaves in exactly the same way as the invocation

      str.substring(begin, end)

      This method is defined so that the 

      String class can implement the  interface.

      Specified by:

       in interface 

      Parameters:

      beginIndex - the begin index, inclusive.

      endIndex - the end index, exclusive.

      Returns:

      the specified subsequence.

      Throws:

       - if 

      beginIndex or 

      endIndex are negative, if 

      endIndex is greater than 

      length(), or if 

      beginIndex is greater than 

      startIndex

      Since:

      1.4
    • concat

      public  concat( str)

      Concatenates the specified string to the end of this string.

      If the length of the argument string is 0, then this String object is returned. Otherwise, a new String object is created, representing a character sequence that is the concatenation of the character sequence represented by this String object and the character sequence represented by the argument string.

      Examples:

      "cares".concat("s") returns "caress" "to".concat("get").concat("her") returns "together"

      Parameters:

      str - the 

      String that is concatenated to the end of this 

      String.

      Returns:

      a string that represents the concatenation of this object's characters followed by the string argument's characters.
    • replace

      public  replace(char oldChar, char newChar)

      Returns a new string resulting from replacing all occurrences of 

      oldCharin this string with 

      newChar.

      If the character oldChar does not occur in the character sequence represented by this String object, then a reference to this String object is returned. Otherwise, a new String object is created that represents a character sequence identical to the character sequence represented by this String object, except that every occurrence of oldChar is replaced by an occurrence of newChar.

      Examples:

      "mesquite in your cellar".replace('e', 'o') returns "mosquito in your collar" "the war of baronets".replace('r', 'y') returns "the way of bayonets" "sparring with a purple porpoise".replace('p', 't') returns "starring with a turtle tortoise" "JonL".replace('q', 'x') returns "JonL" (no change)

      Parameters:

      oldChar - the old character.

      newChar - the new character.

      Returns:

      a string derived from this string by replacing every occurrence of

      oldChar with 

      newChar.
    • matches

      public boolean matches( regex)

      Tells whether or not this string matches the given  .

      An invocation of this method of the form str.matches(regex) yields exactly the same result as the expression

      .(

      regex

      , 

      str

      )

      Parameters:

      regex - the regular expression to which this string is to be matched

      Returns:

      true if, and only if, this string matches the given regular expression

      Throws:

       - if the regular expression's syntax is invalid

      Since:

      1.4

      See Also:
    • contains

      public boolean contains( s)

      Returns true if and only if this string contains the specified sequence of char values.

      Parameters:

      s - the sequence to search for

      Returns:

      true if this string contains 

      s, false otherwise

      Throws:

       - if 

      s is 

      null

      Since:

      1.5
    • replaceFirst

      public  replaceFirst( regex,  replacement)

      Replaces the first substring of this string that matches the given  with the given replacement.

      An invocation of this method of the form str.replaceFirst(regex, repl)yields exactly the same result as the expression

      .(

      regex

      ).(

      str

      ).(

      repl

      )

      Note that backslashes (\) and dollar signs ($) in the replacement string may cause the results to be different than if it were being treated as a literal replacement string; see . Use  to suppress the special meaning of these characters, if desired.

      Parameters:

      regex - the regular expression to which this string is to be matched

      replacement - the string to be substituted for the first match

      Returns:

      The resulting 

      String

      Throws:

       - if the regular expression's syntax is invalid

      Since:

      1.4

      See Also:
    • replaceAll

      public  replaceAll( regex,  replacement)

      Replaces each substring of this string that matches the given   with the given replacement.

      An invocation of this method of the form str.replaceAll(regex, repl)yields exactly the same result as the expression

      .(

      regex

      ).(

      str

      ).(

      repl

      )

      Note that backslashes (\) and dollar signs ($) in the replacement string may cause the results to be different than if it were being treated as a literal replacement string; see . Use to suppress the special meaning of these characters, if desired.

      Parameters:

      regex - the regular expression to which this string is to be matched

      replacement - the string to be substituted for each match

      Returns:

      The resulting 

      String

      Throws:

       - if the regular expression's syntax is invalid

      Since:

      1.4

      See Also:
    • replace

      public  replace( target,  replacement)

      Replaces each substring of this string that matches the literal target sequence with the specified literal replacement sequence. The replacement proceeds from the beginning of the string to the end, for example, replacing "aa" with "b" in the string "aaa" will result in "ba" rather than "ab".

      Parameters:

      target - The sequence of char values to be replaced

      replacement - The replacement sequence of char values

      Returns:

      The resulting string

      Throws:

       - if 

      target or 

      replacement is 

      null.

      Since:

      1.5
    • split

      public [] split( regex, int limit)

      Splits this string around matches of the given  .

      The array returned by this method contains each substring of this string that is terminated by another substring that matches the given expression or is terminated by the end of the string. The substrings in the array are in the order in which they occur in this string. If the expression does not match any part of the input then the resulting array has just one element, namely this string.

      The limit parameter controls the number of times the pattern is applied and therefore affects the length of the resulting array. If the limit nis greater than zero then the pattern will be applied at most n - 1 times, the array's length will be no greater than n, and the array's last entry will contain all input beyond the last matched delimiter. If n is non-positive then the pattern will be applied as many times as possible and the array can have any length. If n is zero then the pattern will be applied as many times as possible, the array can have any length, and trailing empty strings will be discarded.

      The string "boo:and:foo", for example, yields the following results with these parameters:

      Regex	Limit	Result
      :	2	{ "boo", "and:foo" }
      :	5	{ "boo", "and", "foo" }
      :	-2	{ "boo", "and", "foo" }
      o	5	{ "b", "", ":and:f", "", "" }
      o	-2	{ "b", "", ":and:f", "", "" }
      o	0	{ "b", "", ":and:f" }

      An invocation of this method of the form str.split(regex, n) yields the same result as the expression

      .

      (

      regex

      ).

      (

      str

      , 

      n

      )

      Parameters:

      regex - the delimiting regular expression

      limit - the result threshold, as described above

      Returns:

      the array of strings computed by splitting this string around matches of the given regular expression

      Throws:

       - if the regular expression's syntax is invalid

      Since:

      1.4

      See Also:
    • split

      public [] split( regex)

      Splits this string around matches of the given  .

      This method works as if by invoking the two-argument  method with the given expression and a limit argument of zero. Trailing empty strings are therefore not included in the resulting array.

      The string "boo:and:foo", for example, yields the following results with these expressions:

      Regex	Result
      :	{ "boo", "and", "foo" }
      o	{ "b", "", ":and:f" }

      Parameters:

      regex - the delimiting regular expression

      Returns:

      the array of strings computed by splitting this string around matches of the given regular expression

      Throws:

       - if the regular expression's syntax is invalid

      Since:

      1.4

      See Also:
    • toLowerCase

      public  toLowerCase( locale)

      Converts all of the characters in this 

      String to lower case using the rules of the given 

      Locale. Case mapping is based on the Unicode Standard version specified by the   class. Since case mappings are not always 1:1 char mappings, the resulting 

      String may be a different length than the original 

      String.

      Examples of lowercase mappings are in the following table:

      Language Code of Locale	Upper Case	Lower Case	Description
      tr (Turkish)	\u0130	\u0069	capital letter I with dot above -> small letter i
      tr (Turkish)	\u0049	\u0131	capital letter I -> small letter dotless i
      (all)	French Fries	french fries	lowercased all chars in String
      (all)			lowercased all chars in String

      Parameters:

      locale - use the case transformation rules for this locale

      Returns:

      the 

      String, converted to lowercase.

      Since:

      1.1

      See Also:

      ,  , 
    • toLowerCase

      public  toLowerCase()

      Converts all of the characters in this 

      String to lower case using the rules of the default locale. This is equivalent to calling

      toLowerCase(Locale.getDefault()).

      Note: This method is locale sensitive, and may produce unexpected results if used for strings that are intended to be interpreted locale independently. Examples are programming language identifiers, protocol keys, and HTML tags. For instance, "TITLE".toLowerCase() in a Turkish locale returns "t\u0131tle", where '\u0131' is the LATIN SMALL LETTER DOTLESS I character. To obtain correct results for locale insensitive strings, use toLowerCase(Locale.ENGLISH).

      Returns:

      the 

      String, converted to lowercase.

      See Also:
    • toUpperCase

      public  toUpperCase( locale)

      Converts all of the characters in this 

      String to upper case using the rules of the given 

      Locale. Case mapping is based on the Unicode Standard version specified by the   class. Since case mappings are not always 1:1 char mappings, the resulting 

      String may be a different length than the original 

      String.

      Examples of locale-sensitive and 1:M case mappings are in the following table.

      Language Code of Locale	Lower Case	Upper Case	Description
      tr (Turkish)	\u0069	\u0130	small letter i -> capital letter I with dot above
      tr (Turkish)	\u0131	\u0049	small letter dotless i -> capital letter I
      (all)	\u00df	\u0053 \u0053	small letter sharp s -> two letters: SS
      (all)	Fahrvergnügen	FAHRVERGNÜGEN

      Parameters:

      locale - use the case transformation rules for this locale

      Returns:

      the 

      String, converted to uppercase.

      Since:

      1.1

      See Also:

      ,  , 
    • toUpperCase

      public  toUpperCase()

      Converts all of the characters in this 

      String to upper case using the rules of the default locale. This method is equivalent to

      toUpperCase(Locale.getDefault()).

      Note: This method is locale sensitive, and may produce unexpected results if used for strings that are intended to be interpreted locale independently. Examples are programming language identifiers, protocol keys, and HTML tags. For instance, "title".toUpperCase() in a Turkish locale returns "T\u0130TLE", where '\u0130' is the LATIN CAPITAL LETTER I WITH DOT ABOVE character. To obtain correct results for locale insensitive strings, use toUpperCase(Locale.ENGLISH).

      Returns:

      the 

      String, converted to uppercase.

      See Also:
    • trim

      public  trim()

      Returns a copy of the string, with leading and trailing whitespace omitted.

      If this String object represents an empty character sequence, or the first and last characters of character sequence represented by thisString object both have codes greater than '\u0020' (the space character), then a reference to this String object is returned.

      Otherwise, if there is no character with a code greater than '\u0020' in the string, then a new String object representing an empty string is created and returned.

      Otherwise, let k be the index of the first character in the string whose code is greater than '\u0020', and let m be the index of the last character in the string whose code is greater than '\u0020'. A new Stringobject is created, representing the substring of this string that begins with the character at index k and ends with the character at index m-that is, the result of this.substring(k, m+1).

      This method may be used to trim whitespace (as defined above) from the beginning and end of a string.

      Returns:

      A copy of this string with leading and trailing white space removed, or this string if it has no leading or trailing white space.
    • toString

      public  toString()

      This object (which is already a string!) is itself returned.

      Specified by:

       in interface 

      Overrides:

       in class 

      Returns:

      the string itself.
    • toCharArray

      public char[] toCharArray()

      Converts this string to a new character array.

      Returns:

      a newly allocated character array whose length is the length of this string and whose contents are initialized to contain the character sequence represented by this string.
    • format

      public static  format( format, ... args)

      Returns a formatted string using the specified format string and arguments.

      The locale always used is the one returned by .

      Parameters:

      format - A 

      args - Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the  . The behaviour on a 

      null argument depends on the  .

      Returns:

      A formatted string

      Throws:

      IllegalFormatException - If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the   section of the formatter class specification.

       - If the 

      format is 

      null

      Since:

      1.5

      See Also:
    • format

      public static  format( l,  format, ... args)

      Returns a formatted string using the specified locale, format string, and arguments.

      Parameters:

      l - The   to apply during formatting. If 

      l is 

      null then no localization is applied.

      format - A 

      args - Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the  . The behaviour on a 

      null argument depends on the  .

      Returns:

      A formatted string

      Throws:

      IllegalFormatException - If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the   section of the formatter class specification

       - If the 

      format is 

      null

      Since:

      1.5

      See Also:
    • valueOf

      public static  valueOf( obj)

      Returns the string representation of the 

      Object argument.

      Parameters:

      obj - an 

      Object.

      Returns:

      if the argument is 

      null, then a string equal to 

      "null"; otherwise, the value of 

      obj.toString() is returned.

      See Also:
    • valueOf

      public static  valueOf(char[] data)

      Returns the string representation of the 

      char array argument. The contents of the character array are copied; subsequent modification of the character array does not affect the newly created string.

      Parameters:

      data - a 

      char array.

      Returns:

      a newly allocated string representing the same sequence of characters contained in the character array argument.
    • valueOf

      public static  valueOf(char[] data, int offset, int count)

      Returns the string representation of a specific subarray of the 

      chararray argument.

      The offset argument is the index of the first character of the subarray. The count argument specifies the length of the subarray. The contents of the subarray are copied; subsequent modification of the character array does not affect the newly created string.

      Parameters:

      data - the character array.

      offset - the initial offset into the value of the 

      String.

      count - the length of the value of the 

      String.

      Returns:

      a string representing the sequence of characters contained in the subarray of the character array argument.

      Throws:

       - if 

      offset is negative, or 

      count is negative, or 

      offset+count is larger than 

      data.length.
    • copyValueOf

      public static  copyValueOf(char[] data, int offset, int count)

      Returns a String that represents the character sequence in the array specified.

      Parameters:

      data - the character array.

      offset - initial offset of the subarray.

      count - length of the subarray.

      Returns:

      a 

      String that contains the characters of the specified subarray of the character array.
    • copyValueOf

      public static  copyValueOf(char[] data)

      Returns a String that represents the character sequence in the array specified.

      Parameters:

      data - the character array.

      Returns:

      a 

      String that contains the characters of the character array.
    • valueOf

      public static  valueOf(boolean b)

      Returns the string representation of the 

      boolean argument.

      Parameters:

      b - a 

      boolean.

      Returns:

      if the argument is 

      true, a string equal to 

      "true" is returned; otherwise, a string equal to 

      "false" is returned.
    • valueOf

      public static  valueOf(char c)

      Returns the string representation of the 

      char argument.

      Parameters:

      c - a 

      char.

      Returns:

      a string of length 

      1 containing as its single character the argument

      c.
    • valueOf

      public static  valueOf(int i)

      Returns the string representation of the 

      int argument.

      The representation is exactly the one returned by the Integer.toStringmethod of one argument.

      Parameters:

      i - an 

      int.

      Returns:

      a string representation of the 

      int argument.

      See Also:
    • valueOf

      public static  valueOf(long l)

      Returns the string representation of the 

      long argument.

      The representation is exactly the one returned by the Long.toStringmethod of one argument.

      Parameters:

      l - a 

      long.

      Returns:

      a string representation of the 

      long argument.

      See Also:
    • valueOf

      public static  valueOf(float f)

      Returns the string representation of the 

      float argument.

      The representation is exactly the one returned by the Float.toStringmethod of one argument.

      Parameters:

      f - a 

      float.

      Returns:

      a string representation of the 

      float argument.

      See Also:
    • valueOf

      public static  valueOf(double d)

      Returns the string representation of the 

      double argument.

      The representation is exactly the one returned by the Double.toStringmethod of one argument.

      Parameters:

      d - a 

      double.

      Returns:

      a string representation of the 

      double argument.

      See Also:
    • intern

      public  intern()

      Returns a canonical representation for the string object.

      A pool of strings, initially empty, is maintained privately by the classString.

      When the intern method is invoked, if the pool already contains a string equal to this String object as determined by the  method, then the string from the pool is returned. Otherwise, this String object is added to the pool and a reference to this String object is returned.

      It follows that for any two strings s and t, s.intern() == t.intern() istrue if and only if s.equals(t) is true.

      All literal strings and string-valued constant expressions are interned. String literals are defined in §3.10.5 of the 

      Returns:

      a string that has the same contents as this string, but is guaranteed to be from a pool of unique strings.