// C.java
import java.io.Serializable;

public class C implements Serializable {    /* Deserializable Class (Java) warning issued here
                                             * C is explicitly serializable. 
                                             */ 
  private static final long serialVersionUID = 6045080196558799656L;
}

// D.java
public class D {}                           /* Deserializing Non-Serializable Class (Java) warning issued here
                                             * D is not explicitly serializable but does not implement a readObject() method. 
                                             */ 

// B.java
import java.io.ObjectInputStream;

public class B {                                                       // ok: not explicitly serializable, and implements readObject() method (which always throws an exception) 
  private void readObject(ObjectInputStream stream) {
        throw new RuntimeException("Deserialization is not allowed");
  }
}

import java.io.Serializable;

public class C {
  private void readObject(ObjectInputStream stream) {
      throw new RuntimeException("Deserialization is not allowed");
  }
}

public class D {
  private void readObject(ObjectInputStream stream) {
      throw new RuntimeException("Deserialization is not allowed");
  }
}