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This noncompliant snippet implements a GameWeapon class with a serializable field called noofWeapons noOfWeapons, and uses the default serialization form. Any changes to the internal representation of the class can break the existing serialized form.

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

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 you 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 logic. New fields can easily be added without breaking compatibility across releases.

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