Is there a valid class Type variable that can be used with the instanceof operator? For Example:
String s = "abc";
Class<?> classType = String.class;
if (s instanceof classType) {
//do something
}
as an alternative to this:
if (s.getClass() == classType) {
//do something
}
Would there be any performance benefit?
What you're doing is not actually the same. Consider what happens with subclasses (I know you can't subclass String, so in the String case it doesn't matter).
class A {}
class B extends A {}
B b = new B();
b instanceof A // true
b.getClass() == A.class // false
If you have an object and you want to know if it is an instanceof a certain type and you have the Class object, you can use the Class#isInstance method.
In either case, I expect performance differences to be insignificant.
There's also
Class<?> classType = String.class;
if (classType.isInstance(s)) {...
As for performance, I'd expect the differences between any of these to be negligible.
