I have following code:
public class MyClass{
...
}
At same workspace I have following class
public class AnotherClass{
For your case, I think both of (Ctrl +Shift+G) and (Ctrl +Alt+H) work.
To make it more clear:
(Ctrl +Shift+G) is shortkey for Search->References->workspace
Ctrl +Alt+H is short key for Call hierarchy.
Some other useful short keys like: