When you declare a method as abstract method ? can i call a abstract method from a non abstract method ?

A method without body is called abstract method. A abstract method can be called from a non abstract  class or method provided it is inherited using a subclass.

Explanation:

An abstract method is a method which does not have a body, it just has opening and closing curly braces. A class having an abstract method is also declared as abstract class. We cannot make an object of the abstract class.

example : public abstract float multiply(float x, float y);

is an example of abstract method.

calling an abstract method from a non  abstract method is possible provided it is inherited by a non abstract subclass.