overriding – What is @Override for in Java?-ThrowExceptions

Exception or error:

Possible Duplicate:
When do you use Java’s @Override annotation and why?

Is there any reason to annotate a method with @Override other than to have the compiler check that the superclass has that method?

How to solve:

As you describe, @Override creates a compile-time check that a method is being overridden. This is very useful to make sure you do not have a silly signature issue when trying to override.

For example, I have seen the following error:

public class Foo {
  private String id;
  public boolean equals(Foo f) { return id.equals(f.id);}

This class compiles as written, but adding the @Override tag to the equals method will cause a compilation error as it does not override the equals method on Object. This is a simple error, but it can escape the eye of even a seasoned developer


It not only makes the compiler check – although that would be enough to make it useful; it also documents the developer’s intention.

For instance, if you override a method but don’t use it anywhere from the type itself, someone coming to the code later may wonder why on earth it’s there. The annotation explains its purpose.


Nope, you pretty much nailed it.

@Override tells the compiler your intent: if you tag a method @Override, you intended to override something from the superclass (or interface, in Java 6). A good IDE will helpfully flag any method that overrides a method without @Override, so the combination of the two will help ensure that you’re doing what you’re trying to.


nope — except that it also improves readability (i.e. in addition to whatever indicator your IDE uses, it makes it easy to spot that a method overrides a declaration in the superclass)

Leave a Reply

Your email address will not be published. Required fields are marked *