CODEWITHSUNDEEP
java
denniss
denniss

Reputation: 17589

Do two classes of the same class have the same hashcode and are they considered equal?

I want to create a hashmap of classes like (Object.class). I am wondering whether

Object.class is considered equal to another Object.class?

Can there be another instance of Object.class which leads it to have different hashcode?

Upvotes: 4

Views: 243

Answers (3)

peakit
peakit

Reputation: 29359

Since we have only one instance of a .class object for each typed class, all references will be pointing to this same object (of Object.class) and hence will have the same hashcode (as the underlying object is same)

Upvotes: 2

Jon Skeet
Jon Skeet

Reputation: 1500515

The literal Object.class will always return the same reference within the same classloader.

From section 15.8.2 of the JLS:

A class literal evaluates to the Class object for the named type (or for void) as defined by the defining class loader of the class of the current instance.

Note the definite article ("the") in the quote above - there's only one Class object for any particular class, within the same class loader.

So yes, you'll get the same hashcode - because you'll have two references to the same object.

Upvotes: 5

NPE
NPE

Reputation: 500357

Within a given class loader, for each loaded class there's a single object of type Class.

x1.getClass() and x2.getClass() return the same reference as long as x1 and x2 have the same dynamic type.

Upvotes: 2

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