Java Important Programs

package java3;

import java.util.ArrayList;

import java.util.List;

import java.util.Set;

import java.util.TreeSet;

public class met {

                public static int output1;

                public static void fn(String ip1, String ip2) {

                                String s = ip1.replace(" ", "");

                                String s1 = ip2.replace(" ", "");

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

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

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

                                                l1.add(s.charAt(i));

                                for (int j = 0; j < s1.length(); j++)

                                                l2.add(s1.charAt(j));

                                l1.retainAll(l2);

                                Set<Character> set = new TreeSet<Character>(l1);

                                l1 = new ArrayList<Character>(set);

                                output1 = l1.size();

                }

                public static void main(String[] args) {

                                fn("a black cow", "battle ship");

                                System.out.println(output1);

                }

}