Java Nuggets

class A
{

}

class B extends A
{

}

public class Main
{

    public static void main(String[] args)
    {
        A a = new A();
        //A a = null;
        //Also check 
        //A.class.isAssignableFrom(cls);
        B b = new B();
        A ab = new B();

        if (a instanceof A)
        {
            System.out.println("a instanceof A - true");
        }
        else
        {
            System.out.println("a instanceof A - false");
        }

        if (a instanceof B)
        {
            System.out.println("a instanceof B - true");
        }
        else
        {
            System.out.println("a instanceof B - false");
        }

        if (b instanceof A)
        {
            System.out.println("b instanceof A - true");
        }
        else
        {
            System.out.println("b instanceof A - false");
        }

        if (b instanceof B)
        {
            System.out.println("b instanceof B - true");
        }
        else
        {
            System.out.println("b instanceof B - false");
        }

        if (ab instanceof A)
        {
            System.out.println("ab instanceof A - true");
        }
        else
        {
            System.out.println("ab instanceof A - false");
        }

        if (ab instanceof B)
        {
            System.out.println("ab instanceof B - true");
        }
        else
        {
            System.out.println("ab instanceof B - false");
        }

    }
}

Result:
a instanceof A - true
a instanceof B - false
b instanceof A - true
b instanceof B - true
ab instanceof A - true
ab instanceof B - true