Question

Is there any difference in efficiency between the 2 code snippets below? Does the first one require it to allocate memory for the object?

Class c = a.getClass();
if(str != null)
    c.dosomething(c.getX())

if(a.getClass() != null)
    a.getClass().doSomething(a.getClass().getX());

Answer 1

First one will be much more efficient, especially if the getObject method is expensive.
If any memory is allocated for c, this is done inside the getObject method.