Difference between instanceOf and isInstance() ?

First difference:
instanceof is a reserved word of Java, but isInstance(Object obj) is a method of java.lang.Class.

Other differences:
you could use instanceof on types which are known on compile time, and isInstance() could only be called on an instance of java.lang.Class.

if (obj instanceof MyType) {
...
}

if (MyType.class.isInstance(obj)) {
...
}

so you can have dynamism using isInstane() like this:

   Class x = Integer.class;

   if (x.isInstance(obj)) {
   ...
   }

   x = String.class;

   if (x.isInstance(obj)) {
   ...
   }
as you see you could check the type of an object with an unknown class during compile time!