Why doesn't double.class equal java.lang.Double.class?

Question

Since the primitive double is represented with the java.lang.Double class, shouldn't double.class equal java.lang.Double.class? (This of course also happens on other primitive types too)

System.out.println(double.class == Double.class);

Output:

Result: false

Ecbatana

they're different class literals – Lumpish

java.lang.Double wraps/boxes a double, but it’s not the same. – Thermoscope

@Trojaner Because these are different types that don’t behave the same way. For example, you cannot define a List<double>, but you can define a List<Double>. – Thermoscope

(Same reason as a double is not a Double.) – Rolland

Answer 1

Double.class is the class object corresponding to the wrapper type Double. double is actually not a class, but double.class is the object used in reflection to indicate that an argument or return type has primitive type double.

Tanguay

Answer 2

They are two distinct instances of Class<Double>. This doesn't normally happen (for ordinary objects), but for wrapper classes, that's exactly the way to distinguish between fields of the primitive type and the wrapper type in reflection.

Almost

Answer 3

double is a primitive type, Double is a class type. There is a property on the Double class called TYPE:

For example System.out.println(double.class == Double.TYPE); prints true.

Solitude