Method overloading and generics

Question

Java typically prefers normal methods to generic ones when choosing which overloaded method is correct, which could generate the following sscce:

public class GenericsTest {
    public static void main(String[] args) {
        myMethod(Integer.class, 10);
        myMethod(String.class, "overloaded method");
    }

    public static <T> void myMethod(Class<T> klass, T foo) {
        System.out.println("hello world");
    }

    public static <T> void myMethod(Class<T> klass, String bar) {
        System.out.println(bar);
    }
}

Output:

hello world
overloaded method

Is there any way to force Java to use the Generic version?

Answer 1

No, not short of deleting or hiding the more specific overload. Yet, if they behave differently, they should simply have different names. And if they behave the same, it should not matter either way.

Answer 2

One approach I've seen is to add a dummy parameter to the less frequently used method:

public static <T> void myMethod(Class<T> klass, String bar, Void ignored) {
    System.out.println(bar);
}

calling it like

myMethod(String.class, "overloaded method", null);

but otherwise

myMethod(String.class, "overloaded method");

calls the generic method.

Answer 3

Generic methods allow type parameters to be used to express dependencies among the types of one or more arguments to a method and/or its return type. If there isn't such a dependency, a generic method should not be used.

(from here)