Question

I have the following interface in Java

public interface IFoo
{
    public abstract void foo();
    public void bar();
}

What is the difference between foo() and bar()?
When should I use abstract?

Both seem to accomplish what I want unless I’m missing something subtle?

Update Duplicate of Why would one declare a Java interface method as abstract?

Answer 1

There isn’t any functional difference. No implementation is ever provided in a java interface so all method declarations are implicitly abstract.

See [1]: http://java.sun.com/docs/books/tutorial/java/IandI/abstract.html

A direct quote form the above:

Note: All of the methods in an interface (see the Interfaces section) are implicitly abstract, so the abstract modifier is not used with interface methods (it could be—it’s just not necessary).