What methods do all Java objects have?

The equals method for class Object implements the most discriminating possible equivalence relation on objects ; that is, for any non-null reference values x and y , this method returns true if and only if x and y refer to the same object ( x == y has the value true ).

This is how every class has a toString() method : since Object has a toString() method, then ‘children’ of Object inherit a toString() method, the children of children of Object inherit a toString() method, and so on. So every class ‘automatically’ gets a toString() method by inheritance.

There are five of these methods: public final void notify() public final void notifyAll() public final void wait()

An object contains data (instance variables) representing its state, and instance methods , which are the things it can do. A class may also contain its own data (class variables) and class methods.