为什么double.class不等于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

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 .

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.

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.