public class SuperClass {

public SuperClass () {

System.out.println("ini konstruktor milik SuperClass");

}

public void methodSuperClass() {

System.out.println("ini method milik SuperClass");

}

}

public class SubClass extends SuperClass {

public SubClass(){

super ();

}

public void methodSubClass (){

super.methodSuperClass();

}

}

public class DemoInheritance{

public static void main (String[] args) {

SubClass sc = new SubClass ();

sc.methodSubClass();

}

}

public class Persegi{

private double panjang;                //atribut yang disembunyikan

private double lebar;                 //atribut yang disembunyikan

private double tinggi;                //atribut yang disembunyikan

public Persegi () {

panjang = 0;

lebar = 0;

}

private double luas(double p,double l){

return p*l;

}

public void setpanjang (double panjang1){

this.panjang = panjang1;

}

public void setlebar (double lebar1){

this.lebar =lebar1;

}

public double getPanjang(){

return panjang;

}

public double getLebar(){

return lebar;

}

public double getLuas(){

return luas(panjang, lebar);

 }

}

public class MainPersegi{

public static void main (String[] args){

Persegi pg = new Persegi();

pg.setpanjang(10);

pg.setlebar(20);

System.out.println("panjang : "+ pg.getPanjang());

System.out.println("lebar : "+pg.getLebar());

System.out.println("luas : "+pg.getLuas());

}

}

abstract class karyawan {

int gaji;

karyawan () {

gaji = 1000000;

}

int getgaji (){

return gaji;

}

abstract void naikgaji(); }

}

class manager extends karyawan {

manager (){

gaji += 2000000;

}

void naikgaji() { gaji+=3000000;

}

}

class Receptionist extends karyawan {

Receptionist () {

gaji += 1000000;

}

void naikgaji () {gaji+=1000000;}

}

class polymorphisme {

public static void main (String[] args){

karyawan K[] =new karyawan [3];

K[0] = new manager();

K[1] = new Receptionist ();

K[0] = new manager();

for (int i=0;<3 blockquote="blockquote" i="i">

System.out.println("Gaji karyawan "+i+" adalah " +K[i].getgaji());

for (int i=0;i<3 blockquote="blockquote" i="i">

K[i].naikgaji();

for (int i=0;i<3 blockquote="blockquote" i="i">

System.out.println("Gaji sekarang "+i+" adalah" +K[i].getgaji());

} }

public class Disket {

int panjang = 10;

final int lebar = 10;

String warna = "kuning";

String bentuk = "Segi empat";

String data = " ";

Disket (){

panjang = 100;

}

Disket(int panjang1){

this.panjang = panjang1;

}

void simpandata (String data1) {

this.data += data1;

}

void hapusdata(){

data=" ";

}

String bacadata(){

return data;

}

}

class maindisket {

public static void main (String[] args) {

Disket disk1 = new Disket(50);

System.out.println("panjang disket = "+disk1.panjang);

System.out.println("lebar disket = "+disk1.lebar);

System.out.println("warna disket = "+disk1.warna);

System.out.println("bentuk disket = "+disk1.bentuk);

System.out.println("data mula-mula  = "+disk1.bacadata());

disk1.simpandata("Belajar Java");

System.out.println("setelah simpan data = "+disk1.bacadata());

System.out.println("setelah hapusdata = "+disk1.bacadata());

}

}

public class TestTipeData {
public static void main (String[] args) {
byte b = 1;
short s = 100;
int i = 1000;
long l = 10000;
char c = 'a';
float f = 3.14f;
double d = 3.14;
boolean t = true;
final double PI =3.14;
System.out.println("byte " +b);
System.out.println("short " +s);
System.out.println("int " +i);
i=010;
System.out.println("int " +i+ " octal mode");
i= 0XFF;
System.out.println("int "+i+ "hexa mode");
System.out.println("long "+l);
System.out.println("char "+c);
System.out.println("float "+f);
System.out.println("double "+d);
System.out.println("boolean "+t);
System.out.println("PI"+PI);
}
}

class TestKeputusan {

public static void main (String[] args) {

char jeniskelamin = 'W';

//nested if

if (jeniskelamin=='L')

System.out.println ("Cowok");

else if (jeniskelamin=='P')

System.out.println ("Cewek");

else

System.out.println ("Banci");

//ternary

System.out.println(jeniskelamin=='P'? "Dia Pasti Cowok." : "Dia Pasti Cewek");

//switch case

switch (jeniskelamin) {

case'P' : System.out.println ("Cowok");

break;

case 'L': System.out.println ("Cewek");

break;

default : System.out.println("Banci");

break;

}

}

}

Run Aplication Java (ctrl+2)

 public class TestPerulangan {
  public static void main (String[] args) {
  int i;
  //for
  System.out.println ("Perulangan For ...");
  for (i=0; i<10 br="br" i="i">  System.out.println("Perulangan ke : "+i);
  //while
System.out.println("Perulangan While...");
i=0;
while (i<10 br="br"> System.out.println("Perulangan ke : "+i);
i++;
}
//do while
System.out.println("Perulangan Do While...");
i=0;
do {
System.out.println("Perulangan ke : "+i);
i++;
}
while (i<10 br="br">}
}

public class datamahasiswa {

public static void main (String[] args) {

System.out.println("NIM : 200901030130");

System.out.println("Nama : Juindra Benjamin Sihombing");

System.out.println("Alamat : Simpang 2");

}

}

public class nim {
public static void main (String[] args) {
String nim="200901030130";
String nama="Juindra Benjamin Sihombing";
String alamat="Jln. ";
System.out.println("Nim : " + nim);
System.out.println("Nama : " + nama);
System.out.println("Alamat : " + alamat);
}
}

INGAT kata--->'I hate Slow'