substring()

This method is used to cut a portion of the string. substring method has two syntaxes.

Syntax: String substring(int startIndex)
Here we pass only one integer parameter, then the method returns a text starting from that index to end of the string.

public class SubString
{
public static void main(String []args)
{
String str="Tutorial At Home";
System.out.println("Part of the string is : " + str.substring(9));
}
}

Output:
Part of the string is : At Home

String substring(int startIndex,int endindex)
Here we pass two integer parameters, then the method returns a text starting from the first index to the end index end of the string.

public class SubString
{
public static void main(String []args)
{
String str="Tutorial At Home";
System.out.println("Part of the string is : " + str.substring(9,11));
}
}

Output:
Part of the string is : At

split()

split() is a very useful method in Java for handling the string. This method is used to split a string by a specified delimiter.

public class SplitTest
{
public static void main(String []args)
{
String str="Tutorial At Home";
String []words=str.split(" ");
for(int i=0;i<words.length;i++)
{
System.out.println("Word No " + (i+1) + " : " + words[i]);
}
}
}

Output:

Word No 1 : Tutorial
Word No 2 : At
Word No 3 : Home

join()

Join () method is just opposite of split (). It joins the sequence of strings or array of strings by using a specified delimiter.

public class JoinTest
{
public static void main(String []args)
{
String str="Tutorial At Home";
String []words=str.split(" ");
String res=String.join(" ",words);
System.out.println("Joined String is : " + res);
}
}

Output:

Joined String is : Tutorial At Home

equals()

The equals () is used for comparing two strings and return true, if the said strings are same. Otherwise, return false.

public class EqualsTest
{
public static void main(String[] args)
{
String str1 = "Tutorial At Home";
String str2 = "Tutorial At Home";
String str3 = "Tutorial At home";
System.out.println("\"Tutorial At Home\" equals \"Tutorial At Home\" : " + str1.equals(str2));
System.out.println("\"Tutorial At Home\" equals \"Tutorial At home\" : " + str1.equals(str3));
}
}

Output:

"Tutorial At Home" equals "Tutorial At Home" : true
"Tutorial At Home" equals "Tutorial At home" : false

equalsIgnoreCase()

The equalsIgnoreCase () is used for comparing two strings and return true, if the said strings are same. Otherwise, return false. This method is not case sensitive. That is, in this method "A" and "a" is same.

public class EqualsIgnoreCaseTest
{
public static void main(String[] args)
{
String str1 = "Tutorial At Home";
String str2 = "Tutorial At Home";
String str3 = "Tutorial At home";
System.out.println("\"Tutorial At Home\" equals \"Tutorial At Home\" : " + str1.equalsIgnoreCase(str2));
System.out.println("\"Tutorial At Home\" equals \"Tutorial At home\" : " + str1.equalsIgnoreCase(str3));
}
}

Output:

"Tutorial At Home" equals "Tutorial At Home" : true
"Tutorial At Home" equals "Tutorial At home" : true

replaceFirst(), replace() and replaceAll()

These methods are used to replace any sequence of characters by any other sequence of characters. Replace () and replaceAll () methods are same, But first, one replaces any character by another character and replace () replace one sequence of characters by another sequence of characters.

public class ReplaceTest
{
public static void main(String args[])
{
String str = "Tutorial At Home";
System.out.print("Return Value :" );
System.out.println(str.replaceFirst("At", "@"));
System.out.println(str.replaceFirst("a", "@")); 
System.out.println(str.replace("a", "@")); 
System.out.println(str.replaceAll("o", "@")); 
}
}

Output:

Return Value : Tutorial @ Home
Return Value : Tut@rial At Home
Return Value : Tut@rial At H@me
Return Value : Tut@rial At H@me