Is there any way to check whether an object is serializable or not in java?

Question

I found that Object class in java is not serializable in java at the end when i've wasted much time for a problem.
So can anybody knows another class's those are not serializable or any way to check whether that class is serializable?

Answer 1

Yes

if (yourObjectInstance instanceof Serializable) {
    // It is
} else {
    // It is not
}

Note that if yourObjectInstance is null, that would enter the else part as null is not Serializable, no matter what class the reference is about.

Also as Victor Sorokin points out, having a class implements Serializable doesn't mean it can actually be serialized.

Answer 2

If an object is serializable, you should be able to convert it to a byte array. So you can use this test method and make sure that it does not throw an exception when you serialize it.

@Test
public void testIfYourClassIsSerilaizable()  {

    boolean exceptionThrown = false;
    try {
        YourClass obj = new YourClass();
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(bos);
        oos.writeObject(obj);
        oos.flush();
        byte [] data = bos.toByteArray();

    } catch(IOException ex) {
        exceptionThrown = true;
    }
    Assert.assertFalse(exceptionThrown);
}

So based on that , if YourClass or its attributes do not implement Serializable, the above test will throw an exception, making the class not serializable.