What is the difference between equals() method and == operator

== operator:

•  == operator used to compare objects references.
• used to compare data of primitive data types
• if  we are comparing two objects using "==" operator if reference of both are same then it will returns true otherwise returns false.
• obj1==obj2;
• If we are comparing primitive data type variables then it compares data of those two variables
• Ex: int a=12; int b=12; if(a==b) returns true

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 Substring in Java

A part of string is called substring. In other words, substring is a subset of another string. In case of substring startIndex is inclusive and endIndex is exclusive.

Note: Index starts from 0.

You can get substring from the given string object by one of the two methods:

1. public String substring(int startIndex): This method returns new String object containing the substring of the given string from specified startIndex (inclusive).

2. public String substring(int startIndex, int endIndex): This method returns new String object containing the substring of the given string from specified startIndex to endIndex.

In case of string:

• startIndex: inclusive

• endIndex: exclusive

Let's understand the startIndex and endIndex by the code given below.

1. String s="hello";  

2. System.out.println(s.substring(0,2));//he  

In the above substring, 0 points to h but 2 points to e (because end index is exclusive).

Example of java substring

1. public class TestSubstring{  

2.  public static void main(String args[]){  

3.    String s="SouravGanguly";  

4.    System.out.println(s.substring(6));//Ganguly

5.    System.out.println(s.substring(0,6));//Sourav

6.  }  

7. } 

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