Generics

generics.java

public class Generics {
    static class Foo<T, R> {
        public void bar(T arg) {
            System.out.println("T " + arg);
        }

        public void bar(R arg) {
            System.out.println("R " + arg);
        }
    }

    public static void main(String[] args) {
        Foo foo = new Foo<String, Long>();
        foo.bar("abc");
        foo.bar(123);
    }
}