How instanceof is implemented inside JAVA?

Question

Now I\'m writing an ORM Framework and very care about performance.

In this Framework , I have to use instanceof and Class.isAssignableFrom

Answer 1

instanceof is supposed to be faster, it's one bytecode operation

public static void main(String[] args) {
        boolean res1 = args instanceof Object;

bytecode

ALOAD 0
INSTANCEOF java/lang/Object
ISTORE 1

compare to

boolean res2 = Object.class.isAssignableFrom(args.getClass());

bytecode

LDC Ljava/lang/Object;.class
ALOAD 0
INVOKEVIRTUAL java/lang/Object.getClass()Ljava/lang/Class;
INVOKEVIRTUAL java/lang/Class.isAssignableFrom(Ljava/lang/Class;)Z
ISTORE 2