Re: Class hierarchy prolem

I have a class, say MyClass, that consist of a few fields in
particular of a list of other objects:

public MyClass {
  int someID;
  LinkedList<ManyOfThem> bigData;
}

public ManyOfThem {
 // many fields inside
}

I read a file and I create MyClass object from it. My structure of
objects reflects the file format. For each file I calculate some
features:

public MyFeature {
  double theFeatureValue;
  MyClass source;
}

As you see, I keep the computed value and a reference to MyClass
because I need to remember MyClass.someID for some reasons.
Unfortunately Java also keeps in memory all ManyOfThem objects and
there are really many of them!

Unfortunately ManyOfThem objects are necessary to calculate MyFeature.

The problem: I read many files and for each I compute just a few
MyFeature features. Each MyFeature has a reference to MyClass. Because
MyClass keeps also a list of ManyOfThem references, 2GB RAM is not
enough to parse my all data. MyFeature data itself is very small, the
problem is how to get rid of ManyOfThem objects.

In C++ I would use destructor.... What to do in Java to forget about
ManyOfThem objects?

Can I do the following: I split MyClass into two:

public SimplerClass {
  int someID;
}

public MyClass extends SimplerClass {
  LinkedList<ManyOfThem> bigData;
}

And now MyFeature keeps only a reference to the simpler class.
public MyFeature {
  double theFeatureValue;
  SimplerClass source;
}
I guess when I set "source" field to a reference to (SimplerClass)
MyClass. It want solve my problem, will it?

But what if I set:
someFeature.source = ((SimplerClass) myClassObject).clone()

I expect that clone() method from SimplerClass will create a new
object without ManyOfThem stuff. And myClass memory will be free at
some point. Is it correct?

Do you know any simpler/other solution to my problem?

SIncerely yours,
Dominik