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java.lang
public final class

java.lang.String

java.lang.Object
java.lang.String Serializable CharSequence Comparable

An immutable sequence of characters/code units (chars). A String is represented by array of UTF-16 values, such that Unicode supplementary characters (code points) are stored/encoded as surrogate pairs via Unicode code units (char)

See Also

Summary

Constants

      Value  
Comparator  CASE_INSENSITIVE_ORDER       

Public Constructors

          String()
Answers an empty string.
          String(byte[] data)
Converts the byte array to a String using the default encoding as specified by the file.encoding system property.
          String(byte[] data, int high)
This constructor is deprecated. Use String(byte[]) or String(byte[], String) instead
          String(byte[] data, int start, int length)
Converts the byte array to a String using the default encoding as specified by the file.encoding system property.
          String(byte[] data, int high, int start, int length)
This constructor is deprecated. Use String(byte[], int, int) instead
          String(byte[] data, int start, int length, String encoding)
Converts the byte array to a String using the specified encoding.
          String(byte[] data, String encoding)
Converts the byte array to a String using the specified encoding.
          String(char[] data)
Initializes this String to contain the characters in the specified character array.
          String(char[] data, int start, int length)
Initializes this String to contain the specified characters in the character array.
          String(String string)
Creates a string that is a copy of another string
          String(StringBuffer stringbuffer)
Creates a string from the contents of a StringBuffer.
          String(int[] codePoints, int offset, int count)

Constructs a String from the sub-array of Unicode code points.
          String(StringBuilder sb)

Constructs a String from a StringBuilder.

Public Methods

        char  charAt(int index)
Answers the character at the specified offset in this String.
        int  codePointAt(int index)

Retrieves the Unicode code point value at the index.
        int  codePointBefore(int index)

Retrieves the Unicode code point value that precedes the index.
        int  codePointCount(int beginIndex, int endIndex)

Calculates the number of Unicode code points between beginIndex and endIndex.
        int  compareTo(String string)
Compares the specified String to this String using the Unicode values of the characters.
        int  compareToIgnoreCase(String string)
Compare the receiver to the specified String to determine the relative ordering when the case of the characters is ignored.
        String  concat(String string)
Concatenates this String and the specified string.
        boolean  contains(CharSequence cs)

Determines if this String contains the sequence of characters in the CharSequence passed.
        boolean  contentEquals(StringBuffer strbuf)
Answers whether the characters in the StringBuffer strbuf are the same as those in this String.
        boolean  contentEquals(CharSequence cs)

Compares a CharSequence to this String to determine if their contents are equal.
      static  String  copyValueOf(char[] data)
Creates a new String containing the characters in the specified character array.
      static  String  copyValueOf(char[] data, int start, int length)
Creates a new String containing the specified characters in the character array.
        boolean  endsWith(String suffix)
Compares the specified string to this String to determine if the specified string is a suffix.
        boolean  equals(Object object)
Compares the specified object to this String and answer if they are equal.
        boolean  equalsIgnoreCase(String string)
Compares the specified String to this String ignoring the case of the characters and answer if they are equal.
      static  String  format(String format, Object[] args)
Returns a printf-style formatted string, using the supplied format and arguments.
      static  String  format(Locale loc, String format, Object[] args)
Returns a printf-style formatted string, using the supplied format and arguments, accordingly to the specified locale.
        void  getBytes(int start, int end, byte[] data, int index)
This method is deprecated. Use getBytes() or getBytes(String)
        byte[]  getBytes()
Converts this String to a byte encoding using the default encoding as specified by the file.encoding system property.
        byte[]  getBytes(String encoding)
Converts this String to a byte encoding using the specified encoding.
        void  getChars(int start, int end, char[] buffer, int index)
Copies the specified characters in this String to the character array starting at the specified offset in the character array.
        int  hashCode()
Answers an integer hash code for the receiver.
        int  indexOf(int c, int start)
Searches in this String for the index of the specified character.
        int  indexOf(int c)
Searches in this String for the first index of the specified character.
        int  indexOf(String subString, int start)
Searches in this String for the index of the specified string.
        int  indexOf(String string)
Searches in this String for the first index of the specified string.
        String  intern()
Searches an internal table of strings for a string equal to this String.
        int  lastIndexOf(int c)
Searches in this String for the last index of the specified character.
        int  lastIndexOf(String string)
Searches in this String for the last index of the specified string.
        int  lastIndexOf(String subString, int start)
Searches in this String for the index of the specified string.
        int  lastIndexOf(int c, int start)
Searches in this String for the index of the specified character.
        int  length()
Answers the size of this String.
        boolean  matches(String expr)
Determines whether a this String matches a given regular expression.
        int  offsetByCodePoints(int index, int codePointOffset)

Returns the index within this object that is offset from index by codePointOffset code points.
        boolean  regionMatches(int thisStart, String string, int start, int length)
Compares the specified string to this String and compares the specified range of characters to determine if they are the same.
        boolean  regionMatches(boolean ignoreCase, int thisStart, String string, int start, int length)
Compares the specified string to this String and compares the specified range of characters to determine if they are the same.
        String  replace(char oldChar, char newChar)
Copies this String replacing occurrences of the specified character with another character.
        String  replace(CharSequence target, CharSequence replacement)
Copies this String replacing occurrences of the specified target sequence with another sequence.
        String  replaceAll(String expr, String substitute)
Replace any substrings within this String that match the supplied regular expression expr, with the String substitute.
        String  replaceFirst(String expr, String substitute)
Replace the first substring within this String that matches the supplied regular expression expr, with the String substitute.
        String[]  split(String expr, int max)
Splits this String using the supplied regular expression expr.
        String[]  split(String expr)
Splits this String using the supplied regular expression expr.
        boolean  startsWith(String prefix, int start)
Compares the specified string to this String, starting at the specified offset, to determine if the specified string is a prefix.
        boolean  startsWith(String prefix)
Compares the specified string to this String to determine if the specified string is a prefix.
        CharSequence  subSequence(int start, int end)
Has the same result as the substring function, but is present so that String may implement the CharSequence interface.
        String  substring(int start, int end)
Copies a range of characters into a new String.
        String  substring(int start)
Copies a range of characters into a new String.
        char[]  toCharArray()
Copies the characters in this String to a character array.
        String  toLowerCase(Locale locale)
Converts the characters in this String to lowercase, using the specified Locale.
        String  toLowerCase()
Converts the characters in this String to lowercase, using the default Locale.
        String  toString()
Answers a string containing a concise, human-readable description of the receiver.
        String  toUpperCase(Locale locale)
Converts the characters in this String to uppercase, using the specified Locale.
        String  toUpperCase()
Converts the characters in this String to uppercase, using the default Locale.
        String  trim()
Copies this String removing white space characters from the beginning and end of the string.
      static  String  valueOf(float value)
Converts the specified float to its string representation.
      static  String  valueOf(boolean value)
Converts the specified boolean to its string representation.
      static  String  valueOf(double value)
Converts the specified double to its string representation.
      static  String  valueOf(char value)
Converts the specified character to its string representation.
      static  String  valueOf(char[] data)
Creates a new String containing the characters in the specified character array.
      static  String  valueOf(char[] data, int start, int length)
Creates a new String containing the specified characters in the character array.
      static  String  valueOf(long value)
Converts the specified long to its string representation.
      static  String  valueOf(int value)
Converts the specified integer to its string representation.
      static  String  valueOf(Object value)
Converts the specified object to its string representation.
Methods inherited from class java.lang.Object
Methods inherited from interface java.lang.Comparable
Methods inherited from interface java.lang.CharSequence

Details

Constants

public static final Comparator CASE_INSENSITIVE_ORDER

Public Constructors

public String()

Answers an empty string.

public String(byte[] data)

Converts the byte array to a String using the default encoding as specified by the file.encoding system property. If the system property is not defined, the default encoding is ISO8859_1 (ISO-Latin-1). If 8859-1 is not available, an ASCII encoding is used.

Parameters

data the byte array to convert to a String

Throws

NullPointerException when data is null

See Also

public String(byte[] data, int high)

This constructor is deprecated. Use String(byte[]) or String(byte[], String) instead

Converts the byte array to a String, setting the high byte of every character to the specified value.

Parameters

data the byte array to convert to a String
high the high byte to use

Throws

NullPointerException when data is null

public String(byte[] data, int start, int length)

Converts the byte array to a String using the default encoding as specified by the file.encoding system property. If the system property is not defined, the default encoding is ISO8859_1 (ISO-Latin-1). If 8859-1 is not available, an ASCII encoding is used.

Parameters

data the byte array to convert to a String
start the starting offset in the byte array
length the number of bytes to convert

Throws

IndexOutOfBoundsException when length < 0, start < 0 or start + length > data.length
NullPointerException when data is null

See Also

public String(byte[] data, int high, int start, int length)

This constructor is deprecated. Use String(byte[], int, int) instead

Converts the byte array to a String, setting the high byte of every character to the specified value.

Parameters

data the byte array to convert to a String
high the high byte to use
start the starting offset in the byte array
length the number of bytes to convert

Throws

IndexOutOfBoundsException when length < 0, start < 0 or start + length > data.length
NullPointerException when data is null

public String(byte[] data, int start, int length, String encoding)

Converts the byte array to a String using the specified encoding.

Parameters

data the byte array to convert to a String
start the starting offset in the byte array
length the number of bytes to convert
encoding the encoding

Throws

IndexOutOfBoundsException when length < 0, start < 0 or start + length > data.length
UnsupportedEncodingException when encoding is not supported
NullPointerException when data is null

See Also

public String(byte[] data, String encoding)

Converts the byte array to a String using the specified encoding.

Parameters

data the byte array to convert to a String
encoding the encoding

Throws

UnsupportedEncodingException when encoding is not supported
NullPointerException when data is null

See Also

public String(char[] data)

Initializes this String to contain the characters in the specified character array. Modifying the character array after creating the String has no effect on the String.

Parameters

data the array of characters

Throws

NullPointerException when data is null

public String(char[] data, int start, int length)

Initializes this String to contain the specified characters in the character array. Modifying the character array after creating the String has no effect on the String.

Parameters

data the array of characters
start the starting offset in the character array
length the number of characters to use

Throws

IndexOutOfBoundsException when length < 0, start < 0 or start + length > data.length
NullPointerException when data is null

public String(String string)

Creates a string that is a copy of another string

Parameters

string the String to copy

public String(StringBuffer stringbuffer)

Creates a string from the contents of a StringBuffer.

Parameters

stringbuffer the StringBuffer

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

Constructs a String from the sub-array of Unicode code points.

Parameters

codePoints The array of Unicode code points to convert.
offset The inclusive index into codePoints to begin converting from.
count The number of element in codePoints to copy.

Throws

NullPointerException if codePoints is null.
IllegalArgumentException if any of the elements of codePoints are not valid Unicode code points.
IndexOutOfBoundsException if offset or count are not within the bounds of codePoints.

public String(StringBuilder sb)

Constructs a String from a StringBuilder.

Parameters

sb The StringBuilder to copy from.

Throws

NullPointerException if sb is null.

Public Methods

public char charAt(int index)

Answers the character at the specified offset in this String.

Parameters

index the zero-based index in this string

Returns

  • the character at the index

Throws

IndexOutOfBoundsException when index < 0 or index >= length()

public int codePointAt(int index)

Retrieves the Unicode code point value at the index.

Parameters

index The index to the char code unit within this object.

Returns

  • The Unicode code point value.

Throws

IndexOutOfBoundsException if index is negative or greater than or equal to length().

See Also

public int codePointBefore(int index)

Retrieves the Unicode code point value that precedes the index.

Parameters

index The index to the char code unit within this object.

Returns

  • The Unicode code point value.

Throws

IndexOutOfBoundsException if index is less than 1 or greater than length().

See Also

public int codePointCount(int beginIndex, int endIndex)

Calculates the number of Unicode code points between beginIndex and endIndex.

Parameters

beginIndex The inclusive beginning index of the subsequence.
endIndex The exclusive end index of the subsequence.

Returns

  • The number of Unicode code points in the subsequence.

Throws

IndexOutOfBoundsException if beginIndex is negative or greater than endIndex or endIndex is greater than length().

public int compareTo(String string)

Compares the specified String to this String using the Unicode values of the characters. Answer 0 if the strings contain the same characters in the same order. Answer a negative integer if the first non-equal character in this String has a Unicode value which is less than the Unicode value of the character at the same position in the specified string, or if this String is a prefix of the specified string. Answer a positive integer if the first non-equal character in this String has a Unicode value which is greater than the Unicode value of the character at the same position in the specified string, or if the specified String is a prefix of the this String.

Parameters

string the string to compare

Returns

  • 0 if the strings are equal, a negative integer if this String is before the specified String, or a positive integer if this String is after the specified String

Throws

NullPointerException when string is null

public int compareToIgnoreCase(String string)

Compare the receiver to the specified String to determine the relative ordering when the case of the characters is ignored.

Parameters

string a String

Returns

  • an int < 0 if this String is less than the specified String, 0 if they are equal, and > 0 if this String is greater

public String concat(String string)

Concatenates this String and the specified string.

Parameters

string the string to concatenate

Returns

  • a new String which is the concatenation of this String and the specified String

Throws

NullPointerException if string is null

public boolean contains(CharSequence cs)

Determines if this String contains the sequence of characters in the CharSequence passed.

Parameters

cs The character sequence to search for.

Returns

  • true if the sequence of characters are contained in this object; otherwise false

public boolean contentEquals(StringBuffer strbuf)

Answers whether the characters in the StringBuffer strbuf are the same as those in this String.

Parameters

strbuf the StringBuffer to compare this String to

Returns

  • true when the characters in strbuf are identical to those in this String. If they are not, false will be returned.

Throws

NullPointerException when strbuf is null

public boolean contentEquals(CharSequence cs)

Compares a CharSequence to this String to determine if their contents are equal.

Parameters

cs The character sequence to compare to.

Returns

  • true if equal, otherwise false

public static String copyValueOf(char[] data)

Creates a new String containing the characters in the specified character array. Modifying the character array after creating the String has no effect on the String.

Parameters

data the array of characters

Returns

  • the new String

Throws

NullPointerException if data is null

public static String copyValueOf(char[] data, int start, int length)

Creates a new String containing the specified characters in the character array. Modifying the character array after creating the String has no effect on the String.

Parameters

data the array of characters
start the starting offset in the character array
length the number of characters to use

Returns

  • the new String

Throws

IndexOutOfBoundsException if length < 0, start < 0 or start + length > data.length
NullPointerException if data is null

public boolean endsWith(String suffix)

Compares the specified string to this String to determine if the specified string is a suffix.

Parameters

suffix the string to look for

Returns

  • true when the specified string is a suffix of this String, false otherwise

Throws

NullPointerException if suffix is null

public boolean equals(Object object)

Compares the specified object to this String and answer if they are equal. The object must be an instance of String with the same characters in the same order.

Parameters

object the object to compare

Returns

  • true if the specified object is equal to this String, false otherwise

See Also

public boolean equalsIgnoreCase(String string)

Compares the specified String to this String ignoring the case of the characters and answer if they are equal.

Parameters

string the string to compare

Returns

  • true if the specified string is equal to this String, false otherwise

public static String format(String format, Object[] args)

Returns a printf-style formatted string, using the supplied format and arguments. This function is a shortcut to format(Locale.getDefault(), format, args).

Parameters

format a format string
args arguments to replace format specifiers, may be none

Returns

  • The formatted string

Throws

NullPointerException if the format is null
IllegalArgumentException if the format is invalid

See Also

public static String format(Locale loc, String format, Object[] args)

Returns a printf-style formatted string, using the supplied format and arguments, accordingly to the specified locale.

Parameters

loc the locale to apply; null value means no localization
format a format string
args arguments to replace format specifiers, may be none

Returns

  • The formatted string

Throws

NullPointerException if the format is null
IllegalArgumentException if the format is invalid

See Also

public void getBytes(int start, int end, byte[] data, int index)

This method is deprecated. Use getBytes() or getBytes(String)

Converts this String to a byte array, ignoring the high order bits of each character.

Parameters

start the starting offset of characters to copy
end the ending offset of characters to copy
data the destination byte array
index the starting offset in the byte array

Throws

NullPointerException when data is null
IndexOutOfBoundsException when start < 0, end > length(), index < 0, end - start > data.length - index

public byte[] getBytes()

Converts this String to a byte encoding using the default encoding as specified by the file.encoding system property. If the system property is not defined, the default encoding is ISO8859_1 (ISO-Latin-1). If 8859-1 is not available, an ASCII encoding is used.

Returns

  • the byte array encoding of this String

See Also

public byte[] getBytes(String encoding)

Converts this String to a byte encoding using the specified encoding.

Parameters

encoding the encoding

Returns

  • the byte array encoding of this String

Throws

UnsupportedEncodingException when the encoding is not supported

See Also

public void getChars(int start, int end, char[] buffer, int index)

Copies the specified characters in this String to the character array starting at the specified offset in the character array.

Parameters

start the starting offset of characters to copy
end the ending offset of characters to copy
buffer the destination character array
index the starting offset in the character array

Throws

IndexOutOfBoundsException when start < 0, end > length(), start > end, index < 0, end - start > buffer.length - index
NullPointerException when buffer is null

public int hashCode()

Answers an integer hash code for the receiver. Objects which are equal answer the same value for this method.

Returns

  • the receiver's hash

See Also

public int indexOf(int c, int start)

Searches in this String for the index of the specified character. The search for the character starts at the specified offset and moves towards the end of this String.

Parameters

c the character to find
start the starting offset

Returns

  • the index in this String of the specified character, -1 if the character isn't found

See Also

public int indexOf(int c)

Searches in this String for the first index of the specified character. The search for the character starts at the beginning and moves towards the end of this String.

Parameters

c the character to find

Returns

  • the index in this String of the specified character, -1 if the character isn't found

See Also

public int indexOf(String subString, int start)

Searches in this String for the index of the specified string. The search for the string starts at the specified offset and moves towards the end of this String.

Parameters

subString the string to find
start the starting offset

Returns

  • the index in this String of the specified string, -1 if the string isn't found

Throws

NullPointerException when string is null

See Also

public int indexOf(String string)

Searches in this String for the first index of the specified string. The search for the string starts at the beginning and moves towards the end of this String.

Parameters

string the string to find
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