Question

Is there any way in Java to get the compile time type of a reference at runtime?

Example:

private void doSomething(final Object o)
{
   // do somthing
}

final Number n = 1; 
doSomething(n);

final Object o = 1; 
doSomething(o);

final Integer i = 1; 
doSomething(i);

1st call –> Number

2nd call –> Object

3rd call –> Integer

Edit: This is a very simplified version of the problem. What i am trying to do is to detect(instead of being told) inside a framework metadata about objects being passed. What could happen is, that the method gets first called with an Integer and then with a Double, both declared as Number.

Answer 1

The only way I see is to use overloading. But you would need to specify a overlading method for each class of the inheritance relation to exclude sub classes.

private void doSomething(final Object o)
{
   // do something
}

private void doSomething(final Number n)
{
   // do something
}

private void doSomething(final Integer i)
{
   // do something
}

final Number n = 1;
doSomething(n); // doSomething(final Number) is called.