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Java - Strings


Strings which are widely used in Java programming are a sequence of characters. In the Java programming language, strings are objects.

The Java platform provides the String class to create and manipulate strings.

Creating Strings:

The most direct way to create a string is to write:

String greeting ="Hello world!";

Whenever it encounters a string literal in your code, the compiler creates a String object with its value, in this case, "Hello world!'.

As with any other object, you can create String objects by using the new keyword and a constructor. The String class has eleven constructors that allow you to provide the initial value of the string using different sources, such as an array of characters:

public class StringDemo{
public static void main(String args[]){
char[] helloArray ={'h','e','l','l','o','.'};
String helloString =new String(helloArray);
System.out.println(helloString);
}
}

This would produce the following result:

hello.

Note: The String class necessity to make alot Builder Classes. is immutable, so that once it is of modifications to Strings of created a String object cannot be changed. If there is a characters, then you should use String Buffer & String Builder Classes.

String Length:

Methods used to obtain information about an object are known as accessor methods. One accessor method that you can use with strings is the length() method, which returns the number of characters contained in the string object.

After the following two lines of code have been executed, len equals 17:

public class StringDemo{
public static void main(String args[]){
String palindrome ="Dot saw I was Tod";
int len = palindrome.length();
System.out.println("String Length is : "+ len );
}
}

This would produce the following result:

StringLengthis:17

Concatenating Strings:

The String class includes a method for concatenating two strings:

string1.concat(string2);

This returns a new string that is string1 with string2 added to it at the end. You can also use the concat() method with string literals, as in:

"My name is ".concat("Zara");

Strings are more commonly concatenated with the + operator, as in:

"Hello,"+" world"+"!"

which results in:

"Hello, world!"

Let us look at the following example:

public class StringDemo{
public static void main(String args[]){
String string1 ="saw I was ";
System.out.println("Dot "+ string1 +"Tod");
}
}

This would produce the following result:

Dot saw I was Tod

Creating Format Strings:

You have printf() and format() methods to print output with formatted numbers. The String class has an equivalent class method, format(), that returns a String object rather than a PrintStream object.

Using String's static format() method allows you to create a formatted string that you can reuse, as opposed to a one-time print statement. For example, instead of:

System.out.printf("The value of the float variable is "+
"%f, while the value of the integer "+
"variable is %d, and the string "+
"is %s", floatVar, intVar, stringVar);

you can write:

String fs;
fs =String.format("The value of the float variable is "+
"%f, while the value of the integer "+
"variable is %d, and the string "+
"is %s", floatVar, intVar, stringVar);
System.out.println(fs);

String Methods:

Here is the list of methods supported by String class:

SNMethods with Description
1char charAt(int index)
Returns the character at the specified index.
2int compareTo(Object o)
Compares this String to another Object.
3int compareTo(String anotherString)
Compares two strings lexicographically.
4int compareToIgnoreCase(String str)
Compares two strings lexicographically, ignoring case differences.
5String concat(String str)
Concatenates the specified string to the end of this string.
6boolean contentEquals(StringBuffer sb)
Returns true if and only if this String represents the same sequence of characters as the specified StringBuffer.
7static String copyValueOf(char[] data)
Returns a String that represents the character sequence in the array specified.
8static String copyValueOf(char[] data, int offset, int count)
Returns a String that represents the character sequence in the array specified.
9boolean endsWith(String suffix)
Tests if this string ends with the specified suffix.
10boolean equals(Object anObject)
Compares this string to the specified object.
11boolean equalsIgnoreCase(String anotherString)
Compares this String to another String, ignoring case considerations.
12byte getBytes()
Encodes this String into a sequence of bytes using the platform's default charset, storing the result into a new byte array.
13byte[] getBytes(String charsetName
Encodes this String into a sequence of bytes using the named charset, storing the result into a new byte array.
14void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)
Copies characters from this string into the destination character array.
15int hashCode()
Returns a hash code for this string.
16int indexOf(int ch)
Returns the index within this string of the first occurrence of the specified character.
17int 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.
18int indexOf(String str)
Returns the index within this string of the first occurrence of the specified substring.
19int indexOf(String str, int fromIndex)
Returns the index within this string of the first occurrence of the specified substring, starting at the specified index.
20String intern()
Returns a canonical representation for the string object.
21int lastIndexOf(int ch)
Returns the index within this string of the last occurrence of the specified character.
22int 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.
23int lastIndexOf(String str)
Returns the index within this string of the rightmost occurrence of the specified substring.
24int lastIndexOf(String str, int fromIndex)
Returns the index within this string of the last occurrence of the specified substring, searching backward starting at the specified index.
25int length()
Returns the length of this string.
26boolean matches(String regex)
Tells whether or not this string matches the given regular expression.
27boolean regionMatches(boolean ignoreCase, int toffset, String other, int ooffset, int len)
Tests if two string regions are equal.
28boolean regionMatches(int toffset, String other, int ooffset, int len)
Tests if two string regions are equal.
29String replace(char oldChar, char newChar)
Returns a new string resulting from replacing all occurrences of oldChar in this string with newChar.
30String replaceAll(String regex, String replacement
Replaces each substring of this string that matches the given regular expression with the given replacement.
31String replaceFirst(String regex, String replacement)
Replaces the first substring of this string that matches the given regular expression with the given replacement.
32String[] split(String regex)
Splits this string around matches of the given regular expression.
33String[] split(String regex, int limit)
Splits this string around matches of the given regular expression.
34boolean startsWith(String prefix)
Tests if this string starts with the specified prefix.
35boolean startsWith(String prefix, int toffset)
Tests if this string starts with the specified prefix beginning a specified index.
36CharSequence subSequence(int beginIndex, int endIndex)
Returns a new character sequence that is a subsequence of this sequence.
37String substring(int beginIndex)
Returns a new string that is a substring of this string.
38String substring(int beginIndex, int endIndex)
Returns a new string that is a substring of this string.
39char[] toCharArray()
Converts this string to a new character array.
40String toLowerCase()
Converts all of the characters in this String to lower case using the rules of the default locale.
41String toLowerCase(Locale locale)
Converts all of the characters in this String to lower case using the rules of the given Locale.
42String toString()
This object (which is already a string!) is itself returned.
43String toUpperCase()
Converts all of the characters in this String to upper case using the rules of the default locale.
44String toUpperCase(Locale locale)
Converts all of the characters in this String to upper case using the rules of the given Locale.
45String trim()
Returns a copy of the string, with leading and trailing whitespace omitted.
46static String valueOf(primitive data type x)
Returns the string representation of the passed data type argument.
The above mentioned methods are explained here:

char charAt(int index)

Description:

This method returns the character located at the String's specified index. The string indexes start from zero.

Syntax:

Here is the syntax of this method:

public char charAt(int index)

Parameters:

Here is the detail of parameters:
  • index -- Index of the character to be returned.
Return Value:
  • This method Returns a char at the specified index.
Example:

public class Test{
public static void main(String args[]){
String s ="Strings are immutable";
char result = s.charAt(8); System.out.println(result);
}
}

This produces the following result:

a

int compareTo(Object o)

Description:

There are two variants of this method. First method compares this String to another Object and second method compares two strings lexicographically.

Syntax:

Here is the syntax of this method:

int compareTo(Object o)
or
int compareTo(String anotherString)

Parameters:

Here is the detail of parameters:
  • o -- the Object to be compared.
  • anotherString -- the String to be compared.
Return Value :
  • The value 0 if the argument is a string lexicographically equal to this string; a value less than 0 if the argument is a string lexicographically greater than this string; and a value greater than 0 if the argument is a string lexicographically less than this string.
Example:

public class Test{
public static void main(String args[]){
String str1 ="Strings are immutable";
String str2 ="Strings are immutable";
String str3 ="Integers are not immutable";
int result = str1.compareTo( str2 ); System.out.println(result);
result = str2.compareTo( str3 ); System.out.println(result);
result = str3.compareTo( str1 ); System.out.println(result);
}
}

This produces the following result:

0
10
-10

int compareTo(String anotherString)

Description:

There are two variants of this method. First method compares this String to another Object and second method compares two strings lexicographically.

Syntax:

Here is the syntax of this method:

int compareTo(Object o)
or
int compareTo(String anotherString)

Parameters:

Here is the detail of parameters:
  • o -- the Object to be compared.
  • anotherString -- the String to be compared.
Return Value :
  • The value 0 if the argument is a string lexicographically equal to this string; a value less than 0 if the argument is a string lexicographically greater than this string; and a value greater than 0 if the argument is a string lexicographically less than this string.
Example:

public class Test{
public static void main(String args[]){
String str1 ="Strings are immutable";
String str2 ="Strings are immutable";
String str3 ="Integers are not immutable";
int result = str1.compareTo( str2 );
System.out.println(result);
result = str2.compareTo( str3 );
System.out.println(result);
result = str3.compareTo( str1 );
System.out.println(result);
}
}

This produces the following result:

0
10
-10

int compareToIgnoreCase(String str) Description:

This method compares two strings lexicographically, ignoring case differences.

Syntax:

Here is the syntax of this method:

int compareToIgnoreCase(String str)

Parameters:

Here is the detail of parameters:
  • str -- the String to be compared.
Return Value:
  • This method 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.
Example:
public class Test{
public static void main(String args[]){
String str1 ="Strings are immutable";
String str2 ="Strings are immutable";
String str3 ="Integers are not immutable";
int result = str1.compareToIgnoreCase( str2 );
System.out.println(result);
result = str2.compareToIgnoreCase( str3 );
System.out.println(result);
result = str3.compareToIgnoreCase( str1 );
System.out.println(result);
}
}

This produces the following result:

0
10
-10

String concat(String str) Description:

This method appends one String to the end of another. The method returns a String with the value of the String passed in to the method appended to the end of the String used to invoke this method.

Syntax:

Here is the syntax of this method:

public String concat(String s)

Parameters:

Here is the detail of parameters:
  • s -- the String that is concatenated to the end of this String.
Return Value :
  • This methods returns a string that represents the concatenation of this object's characters followed by the string argument's characters.
Example:

public class Test{
public static void main(String args[]){
String s ="Strings are immutable";
s = s.concat(" all the time");
System.out.println(s); }
}

This produces the following result:

Strings are immutable all the time

boolean contentEquals(StringBuffer sb)

Description:

This method returns true if and only if this String represents the same sequence of characters as the specified in StringBuffer.

Syntax:

Here is the syntax of this method:

public boolean contentEquals(StringBuffer sb)

Parameters:

Here is the detail of parameters:
  • sb -- the StringBuffer to compare.
Return Value:
  • This method returns true if and only if this String represents the same sequence of characters as the specified in StringBuffer, otherwise false.
Example:

public class Test{
public static void main(String args[]){
String str1 ="Not immutable";
String str2 ="Strings are immutable";
StringBuffer str3 =new StringBuffer("Not immutable");
boolean result = str1.contentEquals( str3 );
System.out.println(result);
result = str2.contentEquals( str3 );
System.out.println(result);
}
}

This produces the following result:

true
false

static String copyValueOf(char[] data)

Description:

This method has two different forms:
  • public static String copyValueOf(char[] data): Returns a String that represents the character sequence in the array specified.
  • public static String copyValueOf(char[] data, int offset, int count): Returns a String that represents the character sequence in the array specified.
Syntax:

Here is the syntax of this method:

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

Parameters:

Here is the detail of parameters:
  • data -- the character array.
  • offset -- initial offset of the subarray.
  • count -- length of the subarray.
Return Value :
  • This method returns a String that contains the characters of the character array.
Example:

public class Test{
public static void main(String args[]){
char[]Str1={'h','e','l','l','o',' ','w','o','r','l','d'};
String Str2="";
Str2=Str2.copyValueOf(Str1);
System.out.println("Returned String: "+Str2);
Str2=Str2.copyValueOf(Str1,2,6);
System.out.println("Returned String: "+Str2);
}
}

This produces the following result:

Returned String: hello world
Returned String: llo wo

boolean endsWith(String suffix)

Description:

This method tests if this string ends with the specified suffix.

Syntax:

Here is the syntax of this method:

public boolean endsWith(String suffix)

Parameters:

Here is the detail of parameters:
  • suffix -- the suffix.
Return Value:
  • This method returns true if the character sequence represented by the argument is a suffix of the character sequence represented by this object; false otherwise. 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 equals(Object) method.
Example:

public class Test{
public static void main(String args[]){
String Str=new String("This is really not immutable!!");
boolean retVal;
retVal =Str.endsWith("immutable!!");
System.out.println("Returned Value = "+ retVal );
retVal =Str.endsWith("immu");
System.out.println("Returned Value = "+ retVal );
}
}

This produces the following result:

Returned Value = true
Returned Value = false

boolean equals(Object anObject)

Description:

This method 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.

Syntax:

Here is the syntax of this method:

public boolean equals(Object anObject)

Parameters:

Here is the detail of parameters:
  • anObject -- the object to compare this String against.
Return Value :
  • This method returns true if the String are equal; false otherwise.
Example:

public class Test{
public static void main(String args[]){
String Str1=new String("This is really not immutable!!");
String Str2=Str1;
String Str3=new String("This is really not immutable!!");
boolean retVal;
retVal =Str1.equals(Str2);
System.out.println("Returned Value = "+ retVal );
retVal =Str1.equals(Str3);
System.out.println("Returned Value = "+ retVal );
}
}

This produces the following result:

Returned Value = true
Returned Value = true

boolean equalsIgnoreCase(String anotherString)

Description:

This method 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.

Syntax:

Here is the syntax of this method:

public boolean equalsIgnoreCase(String anotherString)

Parameters:

Here is the detail of parameters:
  • anotherString -- the String to compare this String against
Return Value:
  • This method returns true if the argument is not null and the Strings are equal, ignoring case; false otherwise.
Example:

public class Test{
public static void main(String args[]){
String Str1=new String("This is really not immutable!!");
String Str2=Str1;
String Str3=new String("This is really not immutable!!");
String Str4=new String("This IS REALLY NOT IMMUTABLE!!");
boolean retVal;
retVal =Str1.equals(Str2);
System.out.println("Returned Value = "+ retVal );
retVal =Str1.equals(Str3);
System.out.println("Returned Value = "+ retVal );
retVal =Str1.equalsIgnoreCase(Str4);
System.out.println("Returned Value = "+ retVal );
}
}

This produces the following result:

Returned Value = true
Returned Value = true
Returned Value = true

byte getBytes()

Description:

This method has following two forms:
  • getBytes(String charsetName): Encodes this String into a sequence of bytes using the named charset, storing the result into a new byte array.
  • getBytes(): Encodes this String into a sequence of bytes using the platform's default charset, storing the result into a new byte array.
Syntax:

Here is the syntax of this method:

public byte[] getBytes(String charsetName)
throwsUnsupportedEncodingException
or
public byte[] getBytes()

Parameters:

Here is the detail of parameters:
  • charsetName -- the name of a supported charset.
Return Value:
  • This method returns the resultant byte array
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str1=new String("Welcome to Tutorialspoint.com");
try{
byte[]Str2=Str1.getBytes();
System.out.println("Returned Value "+Str2);
Str2=Str1.getBytes("UTF-8");
System.out.println("Returned Value "+Str2);
Str2=Str1.getBytes("ISO-8859-1");
System.out.println("Returned Value "+Str2);
}catch(UnsupportedEncodingException e){
System.out.println("Unsupported character set");
}
}
}

This produces the following result:

Returned Value [B@192d342
Returned Value [B@15ff48b
Returned Value [B@1b90b39

byte[] getBytes(String charsetName)

Description:

This method has following two forms:
  • getBytes(String charsetName): Encodes this String into a sequence of bytes using the named charset, storing the result into a new byte array.
  • getBytes(): Encodes this String into a sequence of bytes using the platform's default charset, storing the result into a new byte array.
Syntax:

Here is the syntax of this method:

public byte[] getBytes(String charsetName)
throws UnsupportedEncodingException
or
public byte[] getBytes()

Parameters:

Here is the detail of parameters:
  • charsetName -- the name of a supported charset.
Return Value:
  • This method returns the resultant byte array
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str1=new String("Welcome to Tutorialspoint.com");
try{
byte[]Str2=Str1.getBytes();
System.out.println("Returned Value "+Str2);
Str2=Str1.getBytes("UTF-8");
System.out.println("Returned Value "+Str2);
Str2=Str1.getBytes("ISO-8859-1");
System.out.println("Returned Value "+Str2);
}catch(UnsupportedEncodingException e){
System.out.println("Unsupported character set");
}
}
}

This produces the following result:

Returned Value [B@192d342
Returned Value [B@15ff48b
Returned Value [B@1b90b39

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

Description:

This method copies characters from this string into the destination character array.

Syntax:

Here is the syntax of this method:

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

Parameters:

Here is the detail of 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.
Return Value:
  • It does not return any value but throws IndexOutOfBoundsException.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str1=new String("Welcome to Tutorialspoint.com");
char[]Str2=newchar[7];
try{ Str1.getChars(2,9,Str2,0);
System.out.print("Copied Value = ");
System.out.println(Str2);
}catch(Exception ex){
System.out.println("Raised exception...");
}
}
}

This produces the following result:

Copied Value = lcome t


int hashCode()

Description:

This method 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.)

Syntax:

Here is the syntax of this method:

public int hashCode()

Parameters:

Here is the detail of parameters:
  • NA
Return Value:
  • This method returns a hash code value for this object.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.println("Hashcode for Str :"+Str.hashCode());
}
}

This produces the following result:

Hashcode for Str :1186874997

int indexOf(int ch)

Description:

This method has following different variants:
  • public int indexOf(int ch): Returns the index within this string of the first occurrence of the specified character or -1 if the character does not occur.
  • 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 or -1 if the character does not occur.
  • int indexOf(String str): Returns the index within this string of the first occurrence of the specified substring. If it does not occur as a substring, -1 is returned.
  • int indexOf(String str, int fromIndex): Returns the index within this string of the first occurrence of the specified substring, starting at the specified index. If it does not occur, -1 is returned.
Syntax:

Here is the syntax of this method:
public int indexOf(int ch )
or
public int indexOf(int ch,int fromIndex)
or
int indexOf(String str)
or
int indexOf(String str,int fromIndex)

Parameters:

Here is the detail of parameters:
  • ch -- a character.
  • fromIndex -- the index to start the search from.
  • str -- a string.
Return Value:
  • See the description.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
StringSubStr1=new String("Tutorials");
StringSubStr2=new String("Sutorials");
System.out.print("Found Index :");
System.out.println(Str.indexOf('o'));
System.out.print("Found Index :");
System.out.println(Str.indexOf('o',5));
System.out.print("Found Index :");
System.out.println(Str.indexOf(SubStr1));
System.out.print("Found Index :");
System.out.println(Str.indexOf(SubStr1,15));
System.out.print("Found Index :");
System.out.println(Str.indexOf(SubStr2));
}
}

This produces the following result:

Found Index :4
Found Index :9
Found Index :11
Found Index :-1
Found Index :-1

int indexOf(int ch, int fromIndex)

Description:

This method has following different variants:
  • public int indexOf(int ch): Returns the index within this string of the first occurrence of the specified character or -1 if the character does not occur.
  • 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 or -1 if the character does not occur.
  • int indexOf(String str): Returns the index within this string of the first occurrence of the specified substring. If it does not occur as a substring, -1 is returned.
  • int indexOf(String str, int fromIndex): Returns the index within this string of the first occurrence of the specified substring, starting at the specified index. If it does not occur, -1 is returned.
Syntax:

Here is the syntax of this method:

public int indexOf(int ch )
or
public int indexOf(int ch,int fromIndex)
or
int indexOf(String str)
or
int indexOf(String str,int fromIndex)

Parameters:

Here is the detail of parameters:
  • ch -- a character.
  • fromIndex -- the index to start the search from.
  • str -- a string.
Return Value:
  • See the description.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
String SubStr1=new String("Tutorials");
String SubStr2=new String("Sutorials");
System.out.print("Found Index :");
System.out.println(Str.indexOf('o'));
System.out.print("Found Index :");
System.out.println(Str.indexOf('o',5));
System.out.print("Found Index :");
System.out.println(Str.indexOf(SubStr1));
System.out.print("Found Index :");
System.out.println(Str.indexOf(SubStr1,15));
System.out.print("Found Index :");
System.out.println(Str.indexOf(SubStr2));
}
}

This produces the following result:

Found Index :4
Found Index :9
Found Index :11
Found Index :-1
Found Index :-1

int indexOf(String str)

Description:

This method has following different variants:
  • public int indexOf(int ch): Returns the index within this string of the first occurrence of the specified character or -1 if the character does not occur.
  • 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 or -1 if the character does not occur.
  • int indexOf(String str): Returns the index within this string of the first occurrence of the specified substring. If it does not occur as a substring, -1 is returned.
  • int indexOf(String str, int fromIndex): Returns the index within this string of the first occurrence of the specified substring, starting at the specified index. If it does not occur, -1 is returned.
Syntax:

Here is the syntax of this method:

public int indexOf(int ch )
or
public int indexOf(int ch,int fromIndex)
or
int indexOf(String str)
or
int indexOf(String str,int fromIndex)

Parameters:

Here is the detail of parameters:
  • ch -- a character.
  • fromIndex -- the index to start the search from.
  • str -- a string.
Return Value:
  • See the description.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
StringSubStr1=new String("Tutorials");
StringSubStr2=new String("Sutorials");
System.out.print("Found Index :");
System.out.println(Str.indexOf('o'));
System.out.print("Found Index :");
System.out.println(Str.indexOf('o',5));
System.out.print("Found Index :");
System.out.println(Str.indexOf(SubStr1));
System.out.print("Found Index :");
System.out.println(Str.indexOf(SubStr1,15));
System.out.print("Found Index :");
System.out.println(Str.indexOf(SubStr2));
}
}

This produces the following result:

Found Index :4
Found Index :9
Found Index :11
Found Index :-1
Found Index :-1

int indexOf(String str, int fromIndex)

Description:

This method has following different variants:
  • public int indexOf(int ch): Returns the index within this string of the first occurrence of the specified character or -1 if the character does not occur.
  • 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 or -1 if the character does not occur.
  • int indexOf(String str): Returns the index within this string of the first occurrence of the specified substring. If it does not occur as a substring, -1 is returned.
  • int indexOf(String str, int fromIndex): Returns the index within this string of the first occurrence of the specified substring, starting at the specified index. If it does not occur, -1 is returned.
Syntax:

Here is the syntax of this method:
public int indexOf(int ch )
or
public int indexOf(int ch,int fromIndex)
or
int indexOf(String str)
or
int indexOf(String str,int fromIndex)

Parameters:

Here is the detail of parameters:
  • ch -- a character.
  • fromIndex -- the index to start the search from.
  • str -- a string.
Return Value:
  • See the description.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
String SubStr1=new String("Tutorials");
String SubStr2=new String("Sutorials");
System.out.print("Found Index :");
System.out.println(Str.indexOf('o'));
System.out.print("Found Index :");
System.out.println(Str.indexOf('o',5));
System.out.print("Found Index :");
System.out.println(Str.indexOf(SubStr1));
System.out.print("Found Index :");
System.out.println(Str.indexOf(SubStr1,15));
System.out.print("Found Index :");
System.out.println(Str.indexOf(SubStr2));
}
}

This produces the following result:

Found Index :4
Found Index :9
Found Index :11
Found Index :-1
Found Index :-1

String intern()

Description:

This method returns a canonical representation for the string object. It follows that for any two strings s and t, s.intern() == t.intern() is true if and only if s.equals(t) is true.

Syntax:

Here is the syntax of this method:

public String intern()

Parameters:

Here is the detail of parameters:
  • NA
Return Value:
  • This method returns a canonical representation for the string object.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str1=new String("Welcome to Tutorialspoint.com");
String Str2=new String("WELCOME TO SUTORIALSPOINT.COM");
System.out.print("Canonical representation:");
System.out.println(Str1.intern());
System.out.print("Canonical representation:");
System.out.println(Str2.intern()); }
}

This produces the following result:

Canonical representation: Welcome to Tutorialspoint.com
Canonical representation: WELCOME TO SUTORIALSPOINT.COM

int lastIndexOf(int ch)

Description:

This method has the following variants:
  • int lastIndexOf(int ch): Returns the index within this string of the last occurrence of the specified character or -1 if the character does not occur.
  • public int lastIndexOf(int ch, int fromIndex): 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.
  • public int lastIndexOf(String str): If the string argument occurs one or more times as a substring within this object, then it returns the index of the first character of the last such substring is returned. If it does not occur as a substring, -1 is returned.
  • public int lastIndexOf(String str, int fromIndex): Returns the index within this string of the last occurrence of the specified substring, searching backward starting at the specified index.
Syntax:

Here is the syntax of this method:

int lastIndexOf(int ch)
or
public int lastIndexOf(int ch,int fromIndex)
or
public int lastIndexOf(String str)
or
public int lastIndexOf(String str,int fromIndex)

Parameters:

Here is the detail of parameters:
  • ch -- a character.
  • fromIndex -- the index to start the search from.
  • str -- A string.
Return Value:
  • This method returns the index.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
String SubStr1=new String("Tutorials");
String SubStr2=new String("Sutorials");
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf('o'));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf('o',5));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf(SubStr1));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf(SubStr1,15));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf(SubStr2));
}
}

This produces the following result:

Found Last Index :27
Found Last Index :4
Found Last Index :11
Found Last Index :11
Found Last Index :-1

int lastIndexOf(int ch, int fromIndex)

Description:

This method has the following variants:
  • int lastIndexOf(int ch): Returns the index within this string of the last occurrence of the specified character or -1 if the character does not occur.
  • public int lastIndexOf(int ch, int fromIndex): 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.
  • public int lastIndexOf(String str): If the string argument occurs one or more times as a substring within this object, then it returns the index of the first character of the last such substring is returned. If it does not occur as a substring, -1 is returned.
  • public int lastIndexOf(String str, int fromIndex): Returns the index within this string of the last occurrence of the specified substring, searching backward starting at the specified index.
Syntax:

Here is the syntax of this method:

int lastIndexOf(int ch)
or
public int lastIndexOf(int ch,int fromIndex)
or
public int lastIndexOf(String str)
or
public int lastIndexOf(String str,int fromIndex)

Parameters:

Here is the detail of parameters:
  • ch -- a character.
  • fromIndex -- the index to start the search from.
  • str -- A string.
Return Value:
  • This method returns the index.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
String SubStr1=new String("Tutorials");
String SubStr2=new String("Sutorials");
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf('o'));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf('o',5));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf(SubStr1));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf(SubStr1,15));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf(SubStr2));
}
}

This produces the following result:

Found Last Index :27
Found Last Index :4
Found Last Index :11
Found Last Index :11
Found Last Index :-1

int lastIndexOf(String str)

Description:

This method has the following variants:
  • int lastIndexOf(int ch): Returns the index within this string of the last occurrence of the specified character or -1 if the character does not occur.
  • public int lastIndexOf(int ch, int fromIndex): 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.
  • public int lastIndexOf(String str): If the string argument occurs one or more times as a substring within this object, then it returns the index of the first character of the last such substring is returned. If it does not occur as a substring, -1 is returned.
  • public int lastIndexOf(String str, int fromIndex): Returns the index within this string of the last occurrence of the specified substring, searching backward starting at the specified index.
Syntax:

Here is the syntax of this method:

int lastIndexOf(int ch)
or
public int lastIndexOf(int ch,int fromIndex)
or
public int lastIndexOf(String str)
or
public int lastIndexOf(String str,int fromIndex)

Parameters:

Here is the detail of parameters:
  • ch -- a character.
  • fromIndex -- the index to start the search from.
  • str -- A string.
Return Value:
  • This method returns the index.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
String SubStr1=new String("Tutorials");
String SubStr2=new String("Sutorials");
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf('o'));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf('o',5));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf(SubStr1));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf(SubStr1,15));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf(SubStr2));
}
}

This produces the following result:

Found Last Index :27
Found Last Index :4
Found Last Index :11
Found Last Index :11
Found Last Index :-1

int lastIndexOf(String str, int fromIndex)

Description:

This method has the following variants:
  • int lastIndexOf(int ch): Returns the index within this string of the last occurrence of the specified character or -1 if the character does not occur.
  • public int lastIndexOf(int ch, int fromIndex): 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.
  • public int lastIndexOf(String str): If the string argument occurs one or more times as a substring within this object, then it returns the index of the first character of the last such substring is returned. If it does not occur as a substring, -1 is returned.
  • public int lastIndexOf(String str, int fromIndex): Returns the index within this string of the last occurrence of the specified substring, searching backward starting at the specified index.
Syntax:

Here is the syntax of this method:

int lastIndexOf(int ch)
or
public int lastIndexOf(int ch,int fromIndex)
or
public int lastIndexOf(String str)
or
public int lastIndexOf(String str,int fromIndex)

Parameters:

Here is the detail of parameters:
  • ch -- a character.
  • fromIndex -- the index to start the search from.
  • str -- A string.
Return Value:
  • This method returns the index.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
String SubStr1=new String("Tutorials");
String SubStr2=new String("Sutorials");
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf('o'));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf('o',5));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf(SubStr1));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf(SubStr1,15));
System.out.print("Found Last Index :");
System.out.println(Str.lastIndexOf(SubStr2));
}
}

This produces the following result:

Found Last Index :27
Found Last Index :4
Found Last Index :11
Found Last Index :11
Found Last Index :-1

int length()

Description:

This method returns the length of this string. The length is equal to the number of 16-bit Unicode characters in the string.

Syntax:

Here is the syntax of this method:

public int length()

Parameters:

Here is the detail of parameters:
  • NA
Return Value:
  • This method returns the the length of the sequence of characters represented by this object.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str1=new String("Welcome to Tutorialspoint.com");
String Str2=new String("Tutorials");
System.out.print("String Length :");
System.out.println(Str1.length());
System.out.print("String Length :");
System.out.println(Str2.length());
}
}

This produces the following result:

String Length :29
String Length :9

boolean matches(String regex)


Description:

This method tells whether or not this string matches the given regular expression. An invocation of this method of the form str.matches(regex) yields exactly the same result as the expression Pattern.matches(regex, str).

Syntax:

Here is the syntax of this method:

public boolean matches(String regex)

Parameters:

Here is the detail of parameters:
  • regex -- the regular expression to which this string is to be matched.
Return Value:
  • This method returns true if, and only if, this string matches the given regular expression.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.matches("(.*)Tutorials(.*)"));
System.out.print("Return Value :");
System.out.println(Str.matches("Tutorials"));
System.out.print("Return Value :");
System.out.println(Str.matches("Welcome(.*)"));
}
}

This produces the following result:

Return Value :true
Return Value :false
Return Value :true

boolean regionMatches(boolean ignoreCase,inttoffset, String other, int ooffset, int len)

Description:

This method has two variants which can be used to test if two string regions are equal.

Syntax:

Here is the syntax of this method:

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

Parameters:

Here is the detail of 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.
  • ignoreCase -- if true, ignore case when comparing characters.
Return Value:
  • It 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 ignoreCase argument.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str1=new String("Welcome to Tutorialspoint.com");
String Str2=new String("Tutorials");
String Str3=new String("TUTORIALS");
System.out.print("Return Value :");
System.out.println(Str1.regionMatches(11,Str2,0,9));
System.out.print("Return Value :");
System.out.println(Str1.regionMatches(11,Str3,0,9));
System.out.print("Return Value :");
System.out.println(Str1.regionMatches(true,11,Str3,0,9));
}
}

This produces the following result:

Return Value :true Return Value :false Return Value :true

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

Description:

This method has two variants which can be used to test if two string regions are equal.

Syntax:

Here is the syntax of this method:

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

Parameters:

Here is the detail of 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.
  • ignoreCase -- if true, ignore case when comparing characters.
Return Value:
  • It 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 ignoreCase argument.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str1=new String("Welcome to Tutorialspoint.com");
String Str2=new String("Tutorials");
String Str3=new String("TUTORIALS");
System.out.print("Return Value :");
System.out.println(Str1.regionMatches(11,Str2,0,9));
System.out.print("Return Value :");
System.out.println(Str1.regionMatches(11,Str3,0,9));
System.out.print("Return Value :");
System.out.println(Str1.regionMatches(true,11,Str3,0,9));
}
}

This produces the following result:

Return Value :true
Return Value :false
Return Value :true

String replace(char oldChar, char newChar)

Description:

This method returns a new string resulting from replacing all occurrences of oldChar in this string with newChar.

Syntax:

Here is the syntax of this method:

public String replace(char oldChar,char newChar)

Parameters:

Here is the detail of parameters:
  • oldChar -- the old character.
  • newChar -- the new character.
Return Value:
  • It returns a string derived from this string by replacing every occurrence of oldChar with newChar.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.replace('o','T'));
System.out.print("Return Value :");
System.out.println(Str.replace('l','D'));
}
}

This produces the following result:

Return Value :WelcTme tT TutTrialspTint.cTm
Return Value :WeDcome to TutoriaDspoint.com

String replaceAll(String regex, String replacement )

Description:

This method replaces each substring of this string that matches the given regular expression with the given replacement.

Syntax:

Here is the syntax of this method:

public String replaceAll(String regex,String replacement)

Parameters:

Here is the detail of parameters:
  • regex -- the regular expression to which this string is to be matched.
  • replacement -- the string which would replace found expression.
Return Value:
  • This method returns the resulting String.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.replaceAll("(.*)Tutorials(.*)",
"AMROOD"));
}
}

This produces the following result:

Return Value :AMROOD

String replaceFirst(String regex, String replacement)

Description:

This method replaces the first substring of this string that matches the given regular expression with the given replacement.

Syntax:

Here is the syntax of this method:

public String replaceFirst(String regex,String replacement)

Parameters:

Here is the detail of parameters:
  • regex -- the regular expression to which this string is to be matched.
  • replacement -- the string which would replace found expression.
Return Value :
  • This method returns a resulting String.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.replaceFirst("(.*)Tutorials(.*)",
"AMROOD"));
System.out.print("Return Value :");
System.out.println(Str.replaceFirst("Tutorials","AMROOD"));
}
}

This produces the following result:

Return Value :AMROOD
Return Value :Welcome to AMROODpoint.com

String[] split(String regex)

Description:

This method has two variants and splits this string around matches of the given regular expression.

Syntax:

Here is the syntax of this method:

public String[] split(String regex,int limit)
or
public String[] split(String regex)

Parameters:

Here is the detail of parameters:
  • regex -- the delimiting regular expression.
  • limit -- the result threshold which means how many strings to be returned.
Return Value:
  • It returns the array of strings computed by splitting this string around matches of the given regular expression.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome-to-Tutorialspoint.com");
System.out.println("Return Value :");
for(String retval:Str.split("-",2)){
System.out.println(retval);
}
System.out.println("");
System.out.println("Return Value :");
for(String retval:Str.split("-",3)){
System.out.println(retval);
}
System.out.println("");
System.out.println("Return Value :");
for(String retval:Str.split("-",0)){
System.out.println(retval);
}
System.out.println("");
System.out.println("Return Value :");
for(String retval:Str.split("-")){
System.out.println(retval);
}
}
}

This produces the following result:

Return Value :
Welcome
to-Tutorialspoint.com
Return Value :
Welcome
to
Tutorialspoint.com
Return Value:
Welcome
to
Tutorialspoint.com
Return Value :
Welcome
to
Tutorialspoint.com

String[] split(String regex, int limit)

Description:

This method has two variants and splits this string around matches of the given regular expression.

Syntax:

Here is the syntax of this method:

public String[] split(String regex,int limit)
or
public String[] split(String regex)

Parameters:

Here is the detail of parameters:
  • regex -- the delimiting regular expression.
  • limit -- the result threshold which means how many strings to be returned.
Return Value:
  • It returns the array of strings computed by splitting this string around matches of the given regular expression.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome-to-Tutorialspoint.com");
System.out.println("Return Value :");
for(String retval:Str.split("-",2)){
System.out.println(retval); }
System.out.println("");
System.out.println("Return Value :");
for(String retval:Str.split("-",3)){
System.out.println(retval);
}
System.out.println("");
System.out.println("Return Value :");
for(String retval:Str.split("-",0)){
System.out.println(retval);
}
System.out.println("");
System.out.println("Return Value :");
for(String retval:Str.split("-")){
System.out.println(retval);
}
}
}

This produces the following result:

Return Value :
Welcome
to-Tutorialspoint.com
Return Value :
Welcome
to
Tutorialspoint.com
Return Value:
Welcome
to
Tutorialspoint.com
Return Value :
Welcome
to
Tutorialspoint.com

boolean startsWith(String prefix)

Description:

This method has two variants and tests if a string starts with the specified prefix beginning a specified index or by default at the beginning.

Syntax:

Here is the syntax of this method:

public boolean startsWith(String prefix,int toffset)
or
public boolean startsWith(String prefix)

Parameters:

Here is the detail of parameters:
  • prefix -- the prefix to be matched.
  • toffset -- where to begin looking in the string.
Return Value:
  • It returns true if the character sequence represented by the argument is a prefix of the character sequence represented by this string; false otherwise.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.startsWith("Welcome"));
System.out.print("Return Value :");
System.out.println(Str.startsWith("Tutorials"));
System.out.print("Return Value :");
System.out.println(Str.startsWith("Tutorials",11));
}
}

This produces the following result:

Return Value :true
Return Value :false
Return Value :true

boolean startsWith(String prefix, int toffset)

Description:

This method has two variants and tests if a string starts with the specified prefix beginning a specified index or by default at the beginning.

Syntax:

Here is the syntax of this method:

public boolean startsWith(String prefix,int toffset)
or
public boolean startsWith(String prefix)

Parameters:

Here is the detail of parameters:
  • prefix -- the prefix to be matched.
  • toffset -- where to begin looking in the string.
Return Value:
  • It returns true if the character sequence represented by the argument is a prefix of the character sequence represented by this string; false otherwise.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.startsWith("Welcome"));
System.out.print("Return Value :");
System.out.println(Str.startsWith("Tutorials"));
System.out.print("Return Value :");
System.out.println(Str.startsWith("Tutorials",11));
}
}

This produces the following result:

Return Value :true
Return Value :false
Return Value :true

CharSequence subSequence(int beginIndex, int endIndex)

Description:

This method returns a new character sequence that is a subsequence of this sequence.

Syntax:

Here is the syntax of this method:

public CharSequence subSequence(int beginIndex,int endIndex)

Parameters:

Here is the detail of parameters:
  • beginIndex -- the begin index, inclusive.
  • endIndex -- the end index, exclusive.
Return Value:
  • This method returns the specified subsequence.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.subSequence(0,10));
System.out.print("Return Value :");
System.out.println(Str.subSequence(10,15));
}
}

This produces the following result:

Return Value :Welcome to
Return Value : Tuto

String substring(int beginIndex)

Description:

This method has two variants and 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 or up to endIndex - 1 if second argument is given.

Syntax:

Here is the syntax of this method:

public String substring(int beginIndex)
or
public String substring(int beginIndex,int endIndex)

Parameters:

Here is the detail of parameters:
  • beginIndex -- the begin index, inclusive.
  • endIndex -- the end index, exclusive.
Return Value:
  • The specified substring.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.substring(10));
System.out.print("Return Value :");
System.out.println(Str.substring(10,15));
}
}

This produces the following result:

Return Value : Tutorialspoint.com
Return Value : Tuto

String substring(int beginIndex, int endIndex)

Description:

This method has two variants and 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 or up to endIndex - 1 if second argument is given.

Syntax:

Here is the syntax of this method:

public String substring(int beginIndex)
or
public String substring(int beginIndex,int endIndex)

Parameters:

Here is the detail of parameters:
  • beginIndex -- the begin index, inclusive.
  • endIndex -- the end index, exclusive.
Return Value:
  • The specified substring.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.substring(10));
System.out.print("Return Value :");
System.out.println(Str.substring(10,15));
}
}

This produces the following result:

Return Value : Tutorialspoint.com
Return Value : Tuto

char[]toCharArray()

Description:

This method converts this string to a new character array.

Syntax:

Here is the syntax of this method:

public char[] toCharArray()

Parameters:

Here is the detail of parameters:
  • NA
Return Value:
  • It 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.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.toCharArray());
}
}

This produces the following result:

Return Value :Welcome to Tutorialspoint.com

String toLowerCase()

Description:

This method has two variants. First variant converts all of the characters in this String to lower case using the rules of the given Locale. This is equivalent to calling toLowerCase(Locale.getDefault()).

Second variant takes locale as an argument to be used while converting into lower case.

Syntax:

Here is the syntax of this method:

public String toLowerCase()
or
public String toLowerCase(Locale locale)

Parameters:

Here is the detail of parameters:
  • NA
Return Value:
  • It returns the String, converted to lowercase.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.toLowerCase());
}
}

This produces the following result:

Return Value :welcome to tutorialspoint.com


String toLowerCase(Locale locale)

Description:
This method has two variants. First variant converts all of the characters in this String to lower case using the rules of the given Locale. This is equivalent to calling toLowerCase(Locale.getDefault()).

Second variant takes locale as an argument to be used while converting into lower case.

Syntax:

Here is the syntax of this method:

public String toLowerCase()
or
public String toLowerCase(Locale locale)

Parameters:

Here is the detail of parameters:
  • NA
Return Value:
  • It returns the String, converted to lowercase.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.toLowerCase());
}
}

This produces the following result:

Return Value :welcome to tutorialspoint.com

String toString()

Description:

This method returns itself a string

Syntax:

Here is the syntax of this method:

public String toString()

Parameters:

Here is the detail of parameters:
  • NA
Return Value:
  • This method returns the string itself.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.toString());
}
}

This produces the following result:

Return Value :Welcome to Tutorialspoint.com

String toUpperCase()

Description:

This method has two variants. First variant converts all of the characters in this String to upper case using the rules of the given Locale. This is equivalent to calling toUpperCase(Locale.getDefault()).

Second variant takes locale as an argument to be used while converting into upper case.

Syntax:

Here is the syntax of this method:

public String toUpperCase()
or
public String toUpperCase(Locale locale)

Parameters:

Here is the detail of parameters:
  • NA
Return Value:
  • It returns the String, converted to uppercase.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.toUpperCase());
}
}

This produces the following result:

Return Value :WELCOME TO TUTORIALSPOINT.COM

String toUpperCase(Locale locale)

Description:

This method has two variants. First variant converts all of the characters in this String to upper case using the rules of the given Locale. This is equivalent to calling toUpperCase(Locale.getDefault()).

Second variant takes locale as an argument to be used while converting into upper case.

Syntax:

Here is the syntax of this method:

public String toUpperCase()
or
public String toUpperCase(Locale locale)

Parameters:

Here is the detail of parameters:
  • NA
Return Value:
  • It returns the String, converted to uppercase.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
String Str=new String("Welcome to Tutorialspoint.com");
System.out.print("Return Value :");
System.out.println(Str.toUpperCase());
}
}

This produces the following result:

Return Value :WELCOME TO TUTORIALSPOINT.COM

String trim()

Description:

This method returns a copy of the string, with leading and trailing whitespace omitted.

Syntax:

Here is the syntax of this method:

publicString trim()

Parameters:

Here is the detail of parameters:
  • NA
Return Value:
  • It 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.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){ ");
String Str=new String(" Welcome to Tutorialspoint.com
System.out.print("Return Value :");
System.out.println(Str.trim());
}
}

This produces the following result:

Return Value :Welcome to Tutorialspoint.com

static String valueOf(primitive data type x)

Description:

This method has followings variants, which depend on the passed parameters. This method returns the string representation of the passed argument.
  • valueOf(boolean b): Returns the string representation of the boolean argument.
  • valueOf(char c): Returns the string representation of the char argument.
  • valueOf(char[] data): Returns the string representation of the char array argument.
  • valueOf(char[] data, int offset, int count): Returns the string representation of a specific subarray of the char array argument.
  • valueOf(double d): Returns the string representation of the double argument.
  • valueOf(float f): Returns the string representation of the float argument.
  • valueOf(int i): Returns the string representation of the int argument.
  • valueOf(long l): Returns the string representation of the long argument.
  • valueOf(Object obj): Returns the string representation of the Object argument.
Syntax:

Here is the syntax of this method:

static String valueOf(boolean b)
or
static String valueOf(char c)
or
static String valueOf(char[] data)
or
static String valueOf(char[] data,int offset,int count)
or
static String valueOf(double d)
or
static String valueOf(float f)
or
static String valueOf(int i)
or
static String valueOf(long l)
or
static String valueOf(Object obj)

Parameters:

Here is the detail of parameters:
  • See the description.
Return Value :
  • This method returns the string representation.
Example:

import java.io.*;
public class Test{
public static void main(String args[]){
double d =102939939.939;
boolean b =true;
long l =1232874;
char[] arr ={'a','b','c','d','e','f','g'};
System.out.println("Return Value : "+String.valueOf(d));
System.out.println("Return Value : "+String.valueOf(b));
System.out.println("Return Value : "+String.valueOf(l));
System.out.println("Return Value : "+String.valueOf(arr));
}
}

This produces the following result:

Return Value : 1.02939939939E8
Return Value : true
Return Value : 1232874
Return Value : abcdefg
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