Question

To explain:

public class SomeClass {
  int aNumber = 0;

  public void changeNumber(int number){
    aNumber = number;
  }

  public int getNumber(){
    return aNumber;
  }
} 


public class Testapp {

  public static void main(String[] args) {
    NewClass object1 = new NewClass();
    NewClass object2 = object1;

    object1.changeNumber(5);
    object2.changeNumber(2);
    System.out.println("object1: "+object1.getNumber());
    System.out.println("object2: "+object2.getNumber());
  }
}

This will output:
object1: 2
object2: 2

How would I make it output:
object1: 5
object2: 2

Answer 1

You have two options:

1) Implement a copy constructor:

public SomeClass(SomeClass c) {
  this.aNumber = c.aNumber;
}

And then to create a copy:

SomeClass object2 = new SomeClass(object1);

2) Implement the Cloneable interface and override Object.clone():

public class SomeClass implements Cloneable {
  public SomeClass clone() {
    super.clone();
  }
}

Then to create a copy:

SomeClass object2 = object1.clone();

Note: I have omitted any code that does not change.