Question

I’m still new to Java and I tried to create an inner class and call the method inside main. There is a compilation error saying

Non static variable – This cannot be referenced from a static context

Please help

class Class1{

    public static void main(String args []){
        Class2 myObject = new Class2();
        myObject.newMethod();
    }

    public class Class2{
        public void newMethod(){
            System.out.println("Second class");
        }
    }
}

Answer 1

An inner class needs a reference to an instance of the outer class in order to be constructed. If your class doesn’t logically need that, then use the static modifer to make it “just a nested class”:

public static class Class2 {
    public void newMethod(){
        System.out.println("Second class");
    }
}

EDIT: To create an instance of Class2 as an inner class, you could use something like:

Class1 outer = new Class1();
Class2 myObject = outer.new Class2();

Or more briefly:

Class2 myObject = new Class1().new Class2();

… but unless you really want a reference to an enclosing instance, it’s much simpler to make the class just a nested class.