Java Compare String (== operator)

Java Compare String (== operator) | String equals() method example

This section describes how two string references are compared. You will learn to use == operator and also the equals() method to compare the String. The == operator is used to find if the two variables refer to the same object. While the equals() function is used to find if the content of passed object matches with the object being compared. If you have two String variables and you have to compare the content of these variables then you should use equals() method.

In this section we have provided you with examples of both == operator and the equals() method. You can run the code example given in this tutorial on your computer in Eclipse IDE or from the terminal. You should have Java installed and configured to run the examples.

Video Tutorial: How to compare String in Java?

Here is the video instruction to run the code in Eclipse IDE and see the use of == operator and equals() method.

Following example code is explained in the above video tutorial:


package net.roseindia.examples;

public class CompareString {

	public static void main(String[] args) {
		// Comparing Strings in Java
		String one = "Hello";
		String two = "World";
		String thrid = "Hello";
		String four = thrid;
		
		// ==
		
		if(thrid == four) {
			System.out.println("Equal");
		}else {
			System.out.println("Not Equal");
			
		}
		

		if(one.equals(thrid)) {
			System.out.println("Equal");
		}else {
			System.out.println("Not Equal");
		}
		
	}

}

In the above code we have used equals() method to find if the second string object value is equal to the first one. Here is the screen shot of the program in Eclipse IDE:

String equals example

If two String variables point to the same object then these two variables are called references for the same object. So to check this comparison programmatically, == operator is used. If two variables refer to the same object then this operator returns true value and if they don't then false value is returned. The essential point to remember while comparing strings with this operator is that it compares the references the two strings are pointing to rather than comparing the content of the string. The following program uses this operator to compare the two strings. If both strings are equal, it will display a message "The given strings are equal" otherwise it will show "The given strings are not equal".

Description of code:

This is the method that compares an object values and returns Boolean type value either 'true' or 'false'. If it returns 'true' for the both objects, it will be equal otherwise not. Here in this case you will see that both the strings come out to be same that is because they have been allocated to the same memory.


public class stringmethod{

  public static void main(String[] args){

  String string1 = "Hi";

  String string2 = new String("Hello");

  if (string1 == string2) {

  System.out.println("The strings are equal.");

  } else {

  System.out.println("The strings are unequal.");

  }

  }

}

Output pf the program:

C:\unique>javac stringmethod.java

C:\unique>java stringmethod
The strings are unequal.

C:\unique

Download this example.

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