Question

I’d need to obtain all the objects created by a class. Is there any pre-built method
to do this in Java API?

Answer 1

It’s not built into the API because there’s no such thing as “created by an object” in terms of Java. You could use a cache for this. But it’s not built into Java. You’d have to maintain this. You can save yourself some trouble by using Factory methods so you don’t forget to store it in the cache.

class Creator {

    Set<Stuff> set = new HashSet<Stuff>();

    // each time you create an object, do this
    void foo() {
        Stuff stuff = // what you create
        set.put(stuff);
    }

    // you get them like
    Set<Stuff> objectsCreatedByThis() { return Collections.unmodifiableSet(stuff); }

}

One thing to be concerned about is that this will cause a high potential for memory leaks. You could use WeakReferences to get around this, so that when every other thread loses access to the Object, so does the set. After all, you wouldn’t want your set to just store everything so it never gets GC’d.