Method accepting two different types as parameter

Question

I am writing a method that should accept as its parameter an object of one of two types which do not share a parent type other than Object. For example, the types are Dreams

Answer 1

As I'm using :

void fooFunction(Object o){
Type1 foo=null;
if(o instanceof Type1) foo=(Type1)o;
if(o instanceof Type2) foo=((Type2)o).toType1();
// code
}

But that only works if Type2 can be converted to Type1