when to have abstract methods code example

Example 1: Can abstract methods have static keyword

No, abstract method is a method that's meant to be overridden, 
only the instance methods can be override

Example 2: What are abstract methods in java

An abstract method is the method which does’nt have any body. 
Abstract method is declared with
keyword abstract and semicolon in place of method body.

  public abstract void ();
Ex : public abstract void getDetails();
It is the responsibility of subclass to provide implementation to 
abstract method defined in abstract class