public static void breakSingletonWithSerialization() {
System.out.println();
final String fileName = "singleton.ser";
// getting singleton instance
Singleton instanceOne = Singleton.getInstance();
instanceOne.setValue(10);
try {
// Serialize to a file
ObjectOutput objectOutput = new ObjectOutputStream(new FileOutputStream(fileName));
objectOutput.writeObject(instanceOne);
objectOutput.close();
// now changed the value of singleton
instanceOne.setValue(20);
// Serialize to a file
ObjectInput objectInput = new ObjectInputStream(new FileInputStream(fileName));
Singleton instanceTwo = (Singleton) objectInput.readObject();
objectInput.close();
System.out.println("Instance One Value= " + instanceOne.getValue());
System.out.println("Instance Two Value= " + instanceTwo.getValue());
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
Singleton s = Singleton.getReference();
System.out.println(s.getValue());
Singleton s2 = Singleton.getReference();
s2.setValue(9);
System.out.println(s.getValue());
try {
// Can't do this: compile-time error.
// Singleton s3 = (Singleton)s2.clone();
} catch (Exception e) {
e.printStackTrace(System.err);
}
}
public static void breakSingletonWithClone() {
System.out.println();
final String fileName = "singleton.ser";
// getting singleton instance
Singleton singleton = Singleton.getInstance();
singleton.setValue(10);
try {
Singleton clonedObject = (Singleton) singleton.clone();
System.out.println(clonedObject);
System.out.println(clonedObject.hashCode());
} catch (CloneNotSupportedException e) {
e.printStackTrace();
}
}
