How to pass a type as a method parameter in Java

You could pass a Class<T> in.

private void foo(Class<?> cls) {
    if (cls == String.class) { ... }
    else if (cls == int.class) { ... }
}

private void bar() {
    foo(String.class);
}

Update: the OOP way depends on the functional requirement. Best bet would be an interface defining foo() and two concrete implementations implementing foo() and then just call foo() on the implementation you’ve at hand. Another way may be a Map<Class<?>, Action> which you could call by actions.get(cls). This is easily to be combined with an interface and concrete implementations: actions.get(cls).foo().