Java Programs easy way

package java2;

import java.util.ArrayList;

import java.util.List;

public class met {

      public static int output1;

      public static void fn(int[] ip1, int[] ip2) {

            List<Integer> l1 = new ArrayList<Integer>();

            List<Integer> l2 = new ArrayList<Integer>();

            int sum = 0;

            for (int i = 0; i < ip1.length; i++) {

                  l1.add(ip1[i]);

            }

            for (int i = 0; i < ip1.length; i++) {

                  l2.add(ip2[i]);

            }

            l1.retainAll(l2);

            if (l1.isEmpty())

                  output1 = -1;

            else {

                  for (int i = 0; i < l1.size(); i++) {

                        sum = sum + l1.get(i);

                  }

                  output1 = sum;

            }

      }

      public static void main(String[] args) {

            int ip1[] = { 2, 3, 4, 5 }, ip2[] = { 3, 4, 56, 6 };

            fn(ip1, ip2);

            System.out.println(output1);

      }

}