Cannot remove JTable from memory

Question

Hi,
I am new to this forum so please forgive me if I make some naive errors. We are developing a component-based software in which the GUI can respond to a user's click to show a JTable in a JPanel. Because the loading of the JTable might take a while since some of our data can have a million columns (I cannot help that), we used a thread to manage the loading of the JTable. So the process is as followed:
1. In a method called "invokeThread", we first get an instance of the JTable as in the code (IVComponent is an interface that our JTable-derived table implements):
final IVComponent returnComponent = VComponentLoader.getVisualization(tableName);2. Then in the method "invokeThread", we start a thread and uses the SwingUtilities.invokeLater() to load the JTable:
        Thread executeThread = new Thread ("Table Thread") {
            public void run () {
                SwingUtilities.invokeLater (new Runnable () {
                    public void run () {
                        loadTable(returnComponent);                       
        executeThread.start ();3. The "loadTable" method is in the same class as the "invokeThread" class. It loads data into the JTable.
This works fine to load the data into the JTable. However, once the JTable's use is finished and the user wants to get rid of it to save on JVM memory, we allow the user to delete that JTable. Now the reason I am asking for help is that although we can set the JTable to null or set its TableColumnModel to null before setting JTable to null, we found that the TableColumns in the TableColumnModel are still on the heap using Eclipse's memory analyzer or Netbean's profiler. We were surprised that neither tool told us which object held them in memory, though.
We have looked on the web for a while. First we thought the "final" keyword might be the problem but using an instance variable for the class in which the method "invokeThread" resides did not help. We have seen other people reporting similar issues with other swing components but has yet to find a solution or a work-around that works for us.
Thanks in advance for your help.
John

Answer 1

Thanks, PhHein. If we can bribe the GC, we will :-).
I guess my question is whether this is something we need to do to ensure that GC will collect the memory once we set the JTable to null. From what we gathered on the web, one possible reason for the GC not to touch the JTable is that there is another reference to the JTable object (or its sub-components?) that we are not aware of. We saw a few posts mentioning the listeners added by a static object. Don't know if it applies to our situation because although we did not add any listener this way, we don't know whether by using JTable and TableColumnModel, a listener is added for us by a static object.
With limited exposure to the development community, we don't know the scope of the issue we encountered. We have seen a few bug reports in sun development network but they were quite old. If this is a well-known issue for Swing components that is yet to be fully addressed, then we have to bite the bullet for now. If there is a solution either offered by sun or by some experts, we will be grateful if you guys can point the way.
Best,
John