Java.lang.String Class

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Introduction

The java.lang.String class represents character strings. All string literals in Java programs, such as "abc", are implemented as instances of this class.Strings are constant, their values cannot be changed after they are created

Class Declaration

Following is the declaration for java.lang.String class −

public final class String
   extends Object
      implements Serializable, Comparable<String>, CharSequence

Field

Following are the fields for java.lang.String class −

  • static Comparator<String> CASE_INSENSITIVE_ORDER − This is a Comparator that orders String objects as by compareToIgnoreCase.

Class constructors

Sr.No. Constructor & Description
1

String()

This initializes a newly created String object so that it represents an empty character sequence.
2

String(byte[] bytes)

This constructs a new String by decoding the specified array of bytes using the platform's default charset.
3

String(byte[] bytes, Charset charset)

This constructs a new String by decoding the specified array of bytes using the specified charset.
4

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

This constructs a new String by decoding the specified subarray of bytes using the platform's default charset
5

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

This constructs a new String by decoding the specified subarray of bytes using the specified charset.
6

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

This constructs a new String by decoding the specified subarray of bytes using the specified charset.
7

String(byte[] bytes, String charsetName)

This constructs a new String by decoding the specified array of bytes using the specified charset.
8

String(char[] value)

This allocates a new String so that it represents the sequence of characters currently contained in the character array argument.
9

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

This allocates a new String that contains characters from a subarray of the character array argument.
10

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

This allocates a new String that contains characters from a subarray of the Unicode code point array argument.
11

String(String original)

This 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.
12

String(StringBuffer buffer)

This allocates a new string that contains the sequence of characters currently contained in the string buffer argument.
13

String(StringBuilder builder)

This allocates a new string that contains the sequence of characters currently contained in the string builder argument.

Class methods

Sr.No. Method & Description
1 char charAt(int index)

This method returns the char value at the specified index.
2 int codePointAt(int index)

This method returns the character (Unicode code point) at the specified index.
3 int codePointBefore(int index)

This method returns the character (Unicode code point) before the specified index.
4 int codePointCount(int beginIndex, int endIndex)

This method returns the number of Unicode code points in the specified text range of this String.
5 int compareTo(String anotherString)

This method compares two strings lexicographically.
6 int compareToIgnoreCase(String str)

This method compares two strings lexicographically, ignoring case differences.
7 String concat(String str)

This method concatenates the specified string to the end of this string.
8 boolean contains(CharSequence s)

This method ceturns true if and only if this string contains the specified sequence of char values.
9 boolean contentEquals(CharSequence cs)

This method compares this string to the specified CharSequence.
10 boolean contentEquals(StringBuffer sb)

This method compares this string to the specified StringBuffer.
11 static String copyValueOf(char[] data)

This method returns a String that represents the character sequence in the array specified.
12 static String copyValueOf(char[] data, int offset, int count)

This method returns a String that represents the character sequence in the array specified.
13 boolean endsWith(String suffix)

This method tests if this string ends with the specified suffix.
14 boolean equals(Object anObject)

This method compares this string to the specified object.
15 boolean equalsIgnoreCase(String anotherString)

This method compares this String to another String, ignoring case considerations.
16 static String format(Locale l, String format, Object... args)

This method returns a formatted string using the specified locale, format string, and arguments.
17 static String format(String format, Object... args)

This method returns a formatted string using the specified format string and arguments.
18 byte[] getBytes()

This method encodes this String into a sequence of bytes using the platform's default charset, storing the result into a new byte array.
19 byte[] getBytes(Charset charset)

This method encodes this String into a sequence of bytes using the given charset, storing the result into a new byte array.
20 byte[] getBytes(String charsetName)

This method encodes this String into a sequence of bytes using the named charset, storing the result into a new byte array.
21 void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)

This method copies characters from this string into the destination character array.
22 int hashCode()

This method returns a hash code for this string.
23 int indexOf(int ch)

This method returns the index within this string of the first occurrence of the specified character.
24 int indexOf(int ch, int fromIndex)

This method returns the index within this string of the first occurrence of the specified character, starting the search at the specified index.
25 int indexOf(String str)

This method returns the index within this string of the first occurrence of the specified substring.
26 int indexOf(String str, int fromIndex)

This method returns the index within this string of the first occurrence of the specified substring, starting at the specified index.
27 String intern()

This method returns a canonical representation for the string object.
28 boolean isEmpty()

This method returns true if, and only if, length() is 0.
29 int lastIndexOf(int ch)

This method returns the index within this string of the last occurrence of the specified character.
30 int lastIndexOf(int ch, int fromIndex)

This method returns the index within this string of the last occurrence of the specified character, searching backward starting at the specified index.
31 int lastIndexOf(String str)

This method returns the index within this string of the rightmost occurrence of the specified substring.
32 int lastIndexOf(String str, int fromIndex)

This method returns the index within this string of the last occurrence of the specified substring, searching backward starting at the specified index.
33 int length()

This method returns the length of this string.
34 boolean matches(String regex)

This method tells whether or not this string matches the given regular expression.
35 int offsetByCodePoints(int index, int codePointOffset)

This method returns the index within this String that is offset from the given index by codePointOffset code points.
36 boolean regionMatches(boolean ignoreCase, int toffset, String other, int ooffset, int len)

This method tests if two string regions are equal with case ignored.
37 boolean regionMatches(int toffset, String other, int ooffset, int len)

This method tests if two string regions are equal.
38 String replace(char oldChar, char newChar)

This method returns a new string resulting from replacing all occurrences of oldChar in this string with newChar.
39 String replace(CharSequence target, CharSequence replacement)

This method replaces each substring of this string that matches the literal target sequence with the specified literal replacement sequence.
40 String replaceAll(String regex, String replacement)

This method replaces each substring of this string that matches the given regular expression with the given replacement.
41 String replaceFirst(String regex, String replacement)

This method replaces the first substring of this string that matches the given regular expression with the given replacement.
42 String[] split(String regex)

This method splits this string around matches of the given regular expression.
43 String[] split(String regex, int limit)

This method splits this string around matches of the given regular expression.
44 boolean startsWith(String prefix)

This method tests if this string starts with the specified prefix.
45 boolean startsWith(String prefix, int toffset)

This method tests if the substring of this string beginning at the specified index starts with the specified prefix.
46 CharSequence subSequence(int beginIndex, int endIndex)

This method returns a new character sequence that is a subsequence of this sequence.
47 String substring(int beginIndex)

This method returns a new string that is a substring of this string.
48 String substring(int beginIndex, int endIndex)

This method returns a new string that is a substring of this string.
49 char[] toCharArray()

This method converts this string to a new character array.
50 String toLowerCase()

This method converts all of the characters in this String to lower case using the rules of the default locale.
51 String toLowerCase(Locale locale)

This method converts all of the characters in this String to lower case using the rules of the given Locale.
52 String toString()

This method returns the string itself.
53 String toUpperCase()

This method converts all of the characters in this String to upper case using the rules of the default locale.
54 String toUpperCase(Locale locale)

This method converts all of the characters in this String to upper case using the rules of the given Locale.
55 String trim()

This method returns a copy of the string, with leading and trailing whitespace omitted.
56 static String valueOf(boolean b)

This method returns the string representation of the boolean argument.
57 static String valueOf(char c)

This method returns the string representation of the char argument.
58 static String valueOf(char[] data)

This method returns the string representation of the char array argument.
59 static String valueOf(char[] data, int offset, int count)

This method Returns the string representation of a specific subarray of the char array argument.
60 static String valueOf(double d)

This method returns the string representation of the double argument.
61 static String valueOf(float f)

This method returns the string representation of the float argument.
62 static String valueOf(int i)

This method returns the string representation of the int argument.
63 static String valueOf(long l)

This method returns the string representation of the long argument.
64 static String valueOf(Object obj)

This method returns the string representation of the Object argument.
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