Are instances of Class class guaranteed to be singletons per classloader?

Question

So is it valid to check for class equality in this way:

if (object.getClass() == anotherObject.getClass()) {

}

Probably the answer is yes because Class class does not override equals() so it looks like Object.equals() applies for Class equality. But, I would be interested if this is documented somewhere else. Thanks.

Answer 1

Refer to JLS Section 12.2:

Well-behaved class loaders maintain these properties:

• Given the same name, a good class loader should always return the same class object.
• ...

A malicious class loader could violate these properties. However, it could not undermine the security of the type system, because the Java Virtual Machine guards against this.

So, provided your instances are of classes loaded by the same class loader, you can test using identity.