This is the test code:

Course course = courseService.load(new Long(1));
Quiz quiz = courseService.loadQuizById(new Long(8));
Quiz q = (Quiz)course.getQuizs().iterator().next();
if(quiz.equals(q)) {
System.out.println("TRUEEEEEEEEE");
} else {
System.out.println("FALSEEEE");
}

I stored only a course object and only a quiz object in the db.
Anyway I assure you that "quiz" and "q" are equals.

I won't give the xml because i don't think the problem can be there...these are very simple associations (course has many quiz, and a quiz belong to a course).

I overrided equals and hashCode methods:

public boolean equals(Object obj) {
if (obj == null) {
return false;
}
Quiz o = (Quiz) obj;
return title.equals(o.title) && course.equals(o.course);
}

public int hashCode() {
return title.hashCode();
}

So why they are not equals in that code?
Could be because of the proxy?

If courseService.load has its own session and courseService.loadQuizById also has its own session then q and quiz can be diffrent objects so their courses can be diffrent to.
Try to make equals between object from one session (maby better transaction) or overwrite course.equals and use it as a base class for proxy.

They have the same memory reference! and then title is the same, course is the same (course has a method equals that check its name).

If i added the line
if(this == o) return true;

everything is ok, but i don't understand this behavior...

Try to use getters instead of direct properties in your equals method.