Is it possible in java that using user defined methods in predefined classes?

Answer 1

public void test(int arg1, int arg2) throws Exception{

.......

}

Above is a typical declaration of a user defined method in java.

The first word public defines the access modifier for the method. you can use public or private.

the second word defines the return type of the method. a void represents no return value. you can have int, String, float etc...

third word is the method name. You can have anything except keywords in this

The values inside the parenthesis are the arguments. A method can take any number of arguments

The throws declaration signifies that this method may throw exceptions. The calling method should have code to handle them.

Answer 2

Assuming you don't have access to the source code of the "predefined class", you can still create an inherited class, and add methods to that. Note, however, that an inherited class will not be able to directly access private members of the parent class.

Answer 3

All methods you write in your classes are user defined methods.

ex:

public String getName(){

return "Rocky";

}