Is there any abstract variables in java?

Question

Can variables be abstract in Java? Do constructor support abstract variables? I am not sure but I think the constructor supports static variables. Please clarify my doubt.

Answer 1

In java only classes and methods can be abstract. Variable declarations cannot. However you can have variable declarations whose types are abstract. See example:

public abstract class MyClass { // allowed
   public abstract myMethod(); // allowed
   public MyClass instance; // allowed

   public abstract MyClass instance; // NOT ALLOWED!!
}