How to perform an operation on operands of unknown types?

Question

Java

For example, take the + operation.
Need a feature like this:
Object plus(Object left, Object right) {...}
What:

plus(1, 3); // = 4 (Integer)
plus(1L, 3); // = 4 (Long)
plus(1L, "test"); // = "1test" (String)
plus(1, new Date()); // Exception