How do I call a non static method from a main method?

Question

For example, I am trying to do something like this

public class Test {

    public static void main(String args[]) {

        int[] arr = new int[5];

        arrPrint(arr);
    }

    public void arrPrint(int[] arr) {

        for (int i = 0; i < arr.length; i++)
            System.out.println(arr[i]);

    }
}

I get an error telling me that I can't reference non-static variables from static enviorments. So if that is true how would I ever utilize a non static method inside of a main?

Solution 1

You can't. A non-static method is one that must be called on an instance of your Test class; create an instance of Test to play with in your main method:

public class Test {

    public static void main(String args[]) {
        int[] arr = new int[5];
        arr = new int[] { 1, 2, 3, 4, 5 };

        Test test = new Test();
        test.arrPrint(arr);

    }

    public void arrPrint(int[] arr) {
        for (int i = 0; i < arr.length; i++)
            System.out.println(arr[i]);

    }
}

Solution 2

You can call non-static method only using a class instance, so you have to create it using new keyword.

public class Something {

    public static void main(String args[]) {
        Something something = new Something();
        something.method1();

        new Something().method2();
    }

    public void method1() {
    }

    public void method2() {
    }
}