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class GameWeapon implements Serializable {
  int noOfWeapons = 10;
	    
  public String toString() {
    return String.valueOf(noOfWeapons);
  }
}

Compliant Solution (serialVersionUID)

In this solution, the class has a serialVersionUID which contains a number unique to this version of the class. Any attempt to deserialize a stream with a GameWeapon object of a different version will yield an exception.

class GameWeapon implements Serializable {
  private static final long serialVersionUID = 24L;

  int noOfWeapons = 10;
	    
  public String toString() {
    return String.valueOf(noOfWeapons);
  }
}

Compliant Solution

Ideally, implement Serializable only when the class is not expected to evolve frequently. One way to maintain the original serialized form, at the same time allowing the class to evolve is to use custom serialization with the help of serialPersistentFields. The static and transient fields allow one to specify what should not be serialized whereas the serialPersistentFields field specifies what should be serialized. It also relieves the class from defining the serializable field within the class implementation, decoupling the current implementation from the overall logic. New fields can easily be added without breaking compatibility across releases.

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