What is a setter() method?

Question

hi, i simply want to know what is a setter method() ? is it a predefined method from javadocs ? or any body can define for setting up variable ?

Answer 1

It's the nickname for what is also called a "mutator", and is a method that conforms to the Java Bean specification for modifying the state of a private instance variable and is also one way to promote encapsulation.
Example:
class Foo
    private String bar;
    public setBar(String aBar) // setter
        bar = aBar;
    public getBar() // getter
        return bar;
}