CODEWITHSUNDEEP
javainheritanceserializable
Jérôme Verstrynge
Jérôme Verstrynge

Reputation: 59576

How to make a class inheriting of serializable class not serializable ever?

Let's consider the following code:

public class MyPanel extends JPanel {

    private long secretInfo = ...

}

JPanel is Serializable. However, MyPanel should not be Serializable ever, because it contains sensitive information.

How to cleanly cancel/prevent the inherited Serializable aspect from JPanel?

Upvotes: 1

Views: 1181

Answers (3)

Ryan Stewart
Ryan Stewart

Reputation: 128819

Don't extend JPanel. Problem solved. Try something like this instead:

class MyPanel {
    void doSomething();
    String getSomeValue();
    JPanel getDisplayComponent();
}

MyPanel logically represents a panel in your app, but there's no particular requirement for it to extend JPanel. Composition is often a more powerful relationship.

Upvotes: 2

Binil Thomas
Binil Thomas

Reputation: 13779

You can use one of the following approaches:

public class MyPanel extends JPanel {
    private long secretInfo = ...

    // refuse to be serialized!
    private void writeObject(ObjectOutputStream out) throws IOException {
        throw new IllegalStateException("MyPanel cannot be serialized");
    }
}

or

public class MyPanel extends JPanel {
    // flag the serialization mechanism to ignore
    // sensitive information
    private transient long secretInfo = ...
}

Upvotes: 2

Jordão
Jordão

Reputation: 56467

You mark the fields you don't want to serialize as transient:

private transient long secretInfo = ...

You can still serialize MyPanel, but its sensitive information won't be serialized.

Also, you could consider an alternative design where the sensitive information is stored in a separate non-serializable class.

Upvotes: 4

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