Java String subSequence()

This article will teach you how to get a subsequence from a String. This looks similar to the Java String substring() method, but the substring method returns a new String while the subSequence method returns CharSequence rather than String.

The reason that the subSequence() method is implemented in the String class is that Java 1.4 introduced the CharSequence interface and String implements this interface. This method internally invokes the substring() method.

Post On:	String subSequence() Method in Java
Post Type:	Java Tutorials
Published On:	www.softwaretestingo.com
Applicable For:	Freshers & Experience
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In this article, we will show how to use String subSequence in Java Programming language with an example.

Syntax:

The syntax of the subSequence() method is:

// It will return Character Sequence 
public CharSequence subSequence(int Startig_index, int End_index); 

//In order to use in program
String_Object.subSequence(int Startig_index, int End_Index)

Here the subSequence() method takes 2 input parameters which should be an integer value. The First parameter informs where the extraction will start and the second parameter informs where the extraction will end.

And the String.subSequence method will return the character sequence starting from the Starting_index up to End_index but not included.

public CharSequence subSequence(int beginIndex, int endIndex) 
{
    return this.substring(beginIndex, endIndex);
}

Example Of Java String subSequence(): The code snippet below demonstrates how to use the subSequence() method. This method returns CharSequence from a string.

package com.SoftwareTestingo.JavaBasics;
public class SubSequenceExample 
{
	public static void main(String[] args) 
	{
		String str = "www.SoftwareTestingo.com";
		System.out.println("Last 4 char String: " + str.subSequence(str.length() - 4, str.length()));
		System.out.println("First 4 char String: " + str.subSequence(0, 4));
		System.out.println("website name: " + str.subSequence(4, 20));
		// substring vs subSequence
		//When you are compare with == its comparing Hashcode which is different 
		System.out.println("substring == subSequence ? " + (str.substring(4, 14) == str.subSequence(4, 14)));
		//When you compare with equals(), its comparing value
		System.out.println("substring equals subSequence ? " + (str.substring(4, 14).equals(str.subSequence(4, 14))));
	}
}

String subSequence() With Negative Example: In the below example we will try to execute by entering the negative value in the index position.

package com.SoftwareTestingO.Java.basics;
public class SubSequenceExample2 
{
	public static void main(String[] args) 
	{
		String stringObject = "This example is with negative index";

		CharSequence output = stringObject.subSequence(-10, stringObject.length());
		System.out.println(output);
	}
}

Final Words:

I hope now you are able to understand what is the use of subSequence() in Java. Still, if you have any questions you can ask us in the comment section.