Java: accessing transient object fields inside class

Question

Accessing private transient object fields from any method in class must be controlled with some code. What is the best practice?

private transient MyClass object = null;

internal get method:

private MyClass getObject() {
    if (object == null)
        object = new MyClass();
    return object;
}
// use...
getObject().someWhat();

or "make sure" method:

private void checkObject() {
    if (object == null)
        object = new MyClass();
}
// use...
checkObject();
object.someWhat();

or something clever, more safe or more powerful?

Answer 1

Transient fields are lost at serialization but you need them only after deserialization, so you have to restore them to what you need in the readObject method...

Answer 2

Have to post a new answer about transient because it's too long for a comment. Following code prints

Before: HELLO FOO BAR
After:  HELLO null null


public class Test {

public static void main(String[] args) throws Exception {

    final Foo foo1 = new Foo();
    System.out.println("Before:\t" + foo1.getValue1() + "\t" + foo1.getValue2() + "\t" + foo1.getValue3());
    final File tempFile = File.createTempFile("test", null);
    // to arrange for a file created by this method to be deleted automatically
    tempFile.deleteOnExit();
    final FileOutputStream fos = new FileOutputStream(tempFile);
    final ObjectOutputStream oos = new ObjectOutputStream(fos);
    oos.writeObject(foo1);
    oos.close();
    final FileInputStream fis = new FileInputStream(tempFile);
    final ObjectInputStream ois = new ObjectInputStream(fis);
    final Foo foo2 = (Foo) ois.readObject();
    ois.close();
    System.out.println("After:\t" + foo2.getValue1() + "\t" + foo2.getValue2() + "\t" + foo2.getValue3());

}

static class Foo implements Serializable {

    private static final long serialVersionUID = 1L;
    private String value1 = "HELLO";
    private transient String value2 = "FOO";
    private transient String value3;

    public Foo() {
        super();
        this.value3 = "BAR";
    }

    public String getValue1() {
        return this.value1;
    }

    public String getValue2() {
        return this.value2;
    }

    public String getValue3() {
        return this.value3;
    }
}

}