Is it possible to access a method or an attribute from a class which is not in the same package?

Answer 1

Yes but then you have to use the public access modifier,
and you have to import the class:

import packageName.className;

A small example..

Lets say this is your main class:

import secondclass.SecondClass;

public class TestOnly {

public static void main(String[] args){

SecondClass s = new SecondClass();
s.aMethod();
}
}

And lets say this class is in another package:

// make the class and method public
// else you wont be able to access it

public class SecondClass {

public void aMethod(){
System.out.println("From class SecondClass");
}
}

Answer 2

You need to import the package/element you want to use