Why is this an issue?
An Externalizable
class is one which handles its own Serialization
and deserialization. During deserialization, the first
step in the process is a default instantiation using the class' no-argument constructor. Therefore an Externalizable
class without a
no-arg constructor cannot be deserialized.
Noncompliant code example
public class Tomato implements Externalizable { // Noncompliant; no no-arg constructor
public Tomato (String color, int weight) { ... }
}
Compliant solution
public class Tomato implements Externalizable {
public Tomato() { ... }
public Tomato (String color, int weight) { ... }
}