class Base{}class Derived extends Base{}class HiDerived extends Derived{}/** * 2018/09/11 <
     
      > RTTI * instanceof Class isInstance 等价性 * @author zz2108828 */public class Test{	static void test (Object x) {		System.out.println("-----------Current type: " + x.getClass());		System.out.println("x instance of Base " + (x instanceof Base));		System.out.println("x instance of Derived " + (x instanceof Derived));		System.out.println("x instance of HiDerived " + (x instanceof HiDerived));		System.out.println("Base.isInstance(x) " + Base.class.isInstance(x));		System.out.println("Derived.isInstance(x) " + Derived.class.isInstance(x));		System.out.println("HiDerived.isInstance(x) " + HiDerived.class.isInstance(x));		System.out.println("x.getClass() == Base.class "+ (x.getClass() == Base.class));		System.out.println("x.getClass() == Derived.class " + (x.getClass() == Derived.class));		System.out.println("x.getClass().equals(Base.class) " + x.getClass().equals(Base.class));		System.out.println("x.getClass().equals(Derived.class) "+x.getClass().equals(Derived.class));		System.out.println("x.getClass().isAssignableFrom(Base.class) " +(x.getClass().isAssignableFrom(Base.class)));		System.out.println("x.getClass().isAssignableFrom(Derived.class) " +(x.getClass().isAssignableFrom(Derived.class)));		System.out.println("x.getClass().isAssignableFrom(HiDerived.class) " +(x.getClass().isAssignableFrom(HiDerived.class)));	}	public static void main(String[] args) {		test(new Base());		test(new Derived());	}}
     

-----------Current type: class Base

x instance of Base true

x instance of Derived false

x instance of HiDerived false

Base.isInstance(x) true

Derived.isInstance(x) false

HiDerived.isInstance(x) false

x.getClass() == Base.class true

x.getClass() == Derived.class false

x.getClass().equals(Base.class) true

x.getClass().equals(Derived.class) false

x.getClass().isAssignableFrom(Base.class) true

x.getClass().isAssignableFrom(Derived.class) true

x.getClass().isAssignableFrom(HiDerived.class) true

-----------Current type: class Derived

x instance of Base true

x instance of Derived true

x instance of HiDerived false

Base.isInstance(x) true

Derived.isInstance(x) true

HiDerived.isInstance(x) false

x.getClass() == Base.class false

x.getClass() == Derived.class true

x.getClass().equals(Base.class) false

x.getClass().equals(Derived.class) true

x.getClass().isAssignableFrom(Base.class) false

x.getClass().isAssignableFrom(Derived.class) true

x.getClass().isAssignableFrom(HiDerived.class) true