Java Object Class Tutorial

Introduction

In Java, the Object class is the root class for all classes. Every class in Java is implicitly or explicitly a subclass of Object. It provides some common methods that can be used by all objects in Java.

Common Methods in Object Class

1. toString() Method:

• The toString() method returns a string representation of the object.
• The default implementation in the Object class returns a string consisting of the class name followed by the “@” character and the object’s hashcode.

2. equals(Object obj) Method:

• The equals() method is used to compare the equality of two objects.
• By default, it compares the memory addresses of the two objects. However, it is often overridden in user-defined classes to compare the contents.

3. hashCode() Method:

• The hashCode() method returns a hash code value for the object.
• This method is often overridden in user-defined classes for better hash code computation.

4. getClass() Method:

• The getClass() method returns the runtime class of an object.

Overriding toString(), equals(), and hashCode()

It’s common to override these methods in your custom classes to provide meaningful implementations for your objects. Here’s an example:

Conclusion

Understanding the Object class and its methods is essential when working with Java, as it provides a foundation for object-oriented programming in the language. By overriding methods like toString(), equals(), and hashCode(), you can customize the behavior of your classes to suit your specific needs.