Java String subSequence

Java 1.4 introduced the CharSequence interface and String implements this interface. This is the only reason for the implementation of subSequence() method in String class. Internally it invokes the substring() method.

Java String subSequence

Below code snippet is from String subSequence method implementation.

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

String subSequence method returns a character sequence that is a subsequence of this sequence. An invocation of this method of the form str.subSequence(begin, end) behaves in exactly the same way as the invocation of str.substring(begin, end).

Below is a simple Java String subSequence method example.

StringSubsequence.java

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package com.journaldev.examples;

public class StringSubsequence {

	/**
	 * This class shows usage of String subSequence method
	 * 
	 * @param args
	 */
	public static void main(String[] args) {
		String str = "www.journaldev.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, 14));
		// substring vs subSequence
		System.out.println("substring == subSequence ? " + (str.substring(4, 14) == str.subSequence(4, 14)));
		System.out.println("substring equals subSequence ? " + (str.substring(4, 14).equals(str.subSequence(4, 14))));
	}

}

Output of the above String subSequence example program is:

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Last 4 char String: .com
First 4 char String: www.
website name: journaldev
substring == subSequence ? false
substring equals subSequence ? true

There is no benefit in using subSequence method. Ideally, you should always use String substring method.

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