Java Substring With Example

A string is described as a collection of characters. String objects are immutable in Java, which means they can’t be modified once they’ve been created. A popular question asked in Java interviews is how to find the substring of a string. So, I’ll show you how Substring functions in Java.

Substring in Java: What is a substring in Java?

Programmers often need to retrieve an individual character or a group of characters (substring) from a string. For example, in a word processing program, a part of the string is copied or deleted. While charAt() method returns only a single character from a string, the substring() method in the String class can be used to obtain a substring from a string.

Substring in Java: Different methods under substring

There are two separate methods under the substring() method. They are as follows:

• String substring(int begIndex)
• String substring​(int beginIndex, int endIndex)

String substring(int beginIndex): This method returns a new string that is a substring of the invoking string. The substring returned contains a copy of characters beginning from the specified index beginIndex and extends to the end of the string. For example,

Syntax:

public String substring(int begIndex)

Note: The index begins with ‘0,’ which corresponds to String’s first character.

Let’s take a look at an example.

s1.substring(3); // returns substring 'come'

String substring (int beginIndex, int endIndex): This method is another version of previous method. It also returns a substring that begins at the specified begin Index and extends to the character at index endIndex-1. 

Syntax:

public String substring(int begIndex, int endIndex)

Let’s take a look at an example.

s1.substring(3,6); // returns substring "come".

public class SubstringMethods {
 public static void main(String[] args) { 
  String s1 = "Welcome" ;
  System.out.println("s1.substring(3) = " + s1.substring(3));
  System.out.println("substring(3,6) = " + s1.substring(3));
 }
} 

class StrSubString {
 public static void main(String args[]) {
  String k="Hello Dinesh";
  String m="";
  m = k.substring(6,12);
  System.out.println(m);
 }
}