How to Compare Two Objects with the equals Method in Java

In Brief...

To test whether two objects are equal, a developer should provide an equals method. The logic in the method can determine if the two objects are equal and return true, or return false otherwise. To compare two objects with the equals method, follow these four steps.


  1. Open your text editor and create a new file that will contain the circle class and a main method to test two circles for equality. Type in the following Java statements.
    Java Source for Equals Method
    According to the equals method, two circles are equal if they have the same radius.

  2. Save your file as

  3. Open a command prompt and navigate to the directory containing your Java program. Then type in the command to compile the source and hit Enter.
    Compile Source for Equals Method Program

  4. You are ready to test your program. Type in the command to run the Java runtime launcher and then hit Enter.
    Run the Equals Method Program
    Notice the equals method correctly determined circle1 is equal to circle2. As an exercise, change circle2 to circle3 in the if statement to test circles that are not equal.

Author: Stephen Withrow

Stephen has over 30 years' experience in training, development, and consulting in a variety of technology areas including Java, C, C++, XML, JavaScript, AJAX, Tomcat, JBoss, Oracle, and DB2. His background includes design and implementation of business solutions on client/server, Web, and enterprise platforms. Stephen is a published writer in both technical and non-technical endeavors. Stephen received an undergraduate degree in Computer Science and Physics from Florida State University.