Contoh program java

import java.util.Scanner;

public class utama {

                public static void main (String[] args){

                                int x,y;

                                Scanner putin = new Scanner(System.in);

                                System.out.print("Masukkan angka pertama : ");

                                x=putin.nextInt();

                                System.out.print("Masukkan angka kedua   :");

                                y=putin.nextInt();

                                indec mv = new indec();

                                System.out.println();

                                mv.segitiga();

                                System.out.println();

                                relasi mv1 = new relasi();

                                aritmatika mv2 = new aritmatika();

                                mv1.putnil(x,y);

                                mv2.aritmatika1(x,y);

                                boolean s=mv1.lebih();

                                boolean d=mv1.kurang();

                                int f = mv2.tambah();

                                int j = mv2.kurang();

                                int k = mv2.kali();

                                int l = mv2.modul();

                                float o = mv2.bagi();

                                System.out.println(x+" > "+y+" = "+s);

                                System.out.println(x+" < "+y+" = "+d);

                                System.out.println(x+" + "+y+" = "+f);

                                System.out.println(x+" - "+y+" = "+j);

                                System.out.println(x+" x "+y+" = "+k);

                                System.out.println(x+" % "+y+" = "+l);

                                System.out.println(x+" : "+y+" = "+o);  

                }

                }

public class aritmatika {

                 static int x,y;

public static void aritmatika1(int setx,int sety){

                x=setx;

                y=sety;

}

public int tambah(){return x+y;}

public int kurang(){return x-y;}

public int kali(){return x*y;}

public int modul(){return x%y;}

public float bagi(){return (float)x/(float)y;}

}

public class indec {

 public void segitiga(){

                for (int iwak=5;iwak>0;iwak--){

                                for (int peyek=0;peyek<iwak;peyek++){

                                System.out.print(peyek);

                                }

                                System.out.println();

                }

}}

public class relasi {

                int x,y;

                public void putnil(int a, int b){

                                x=a;

                                y=b;                      

                }

                public boolean lebih(){

                                return x>y;

                }

                public boolean kurang(){

                                return x<y;                        

                               

                }

}

Perhatian :
Nama class harus = nama filenya.!!