Memory Leak in a multi threaded Swing application (ImageIcon)

Question

When I profile my swing application with netbeans 5.5 , I notice that after each periodically tidy up my image container (add,remove IconImage objects to a hashmap or arraylist), there gather by and by surviving objects. This leads to run out of memory after a while. Is there any other way to avoid this effect?
Any ideas about "The JVM is notorious for caching images."
please help..
what I have made briefly:
1.) Read the binary stream from the db :
rs=stmt.executeQuery(query);
if(rs.next()){
    int len=rs.getInt(2);
    byte [] b=new byte[len];
    InputStream in = rs.getBinaryStream(3);
    try {
            in.read(b);
            in.close();
            img=Toolkit.getDefaultToolkit().createImage(b);
     } catch (IOException e) {
            e.printStackTrace();
stmt.close();
rs.close();2.) hold the icon as field :
this.icon =  new ImageIcon(img);3.) After a while I remove the object from my collection and on the
overridden method finalize() I also call the flush() method.
if(this.icon != null){
            this.icon.getImage().flush();
            this.icon = null;
}The surviving objects still increase?! On the page of SUN they
submitted a bug. But this is set on closed/fixed.
(http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4014323)
What am I doing wrong? I also use the byte[] constructor on creating the icon and
my java version is 1.5.0_10.

Answer 1

If in your JFrame u have placed your image, before invoke the dispose()
method put explicitly the image pointer to null and deregister all listener
you have added to any componentI implemented your suggest and after starting a long time test, in one hour there gathered aprox. 500 surviving generations. I attach a snapshot and the java file ( http://www.box.net/public/eqznamrazd ). The used heap size swings between 3MB and 5MB. I guess this wont kill so quickly the application but anyway there is something wrong!
Even properly closed streams, database connections etc.. Really despairing. Could one take a look to the java source?
some snippets bellow:
private class MyImageIcon extends ImageIcon {
        public MyImageIcon(Image img){
            super(img);
        public void removeImage(Image anImage){
            tracker.removeImage(anImage);
private class DetailDialog extends javax.swing.JFrame {
        private String personnr;
        private MyImageIcon icon;
        public DetailDialog(String personnr,MyImageIcon icon){
            this.personnr = personnr;
            this.icon = icon;
        public void dispose() {
            if(icon != null){
                icon.removeImage(icon.getImage());
                icon.getImage().flush();
                icon = null;
            super.dispose();
private class Person extends Object {
        private MyImageIcon icon;
        private String number;
        private DetailDialog detailDialog;
        protected void destroy() {
            if(icon!=null){
                icon.removeImage(icon.getImage());
                icon.getImage().flush();
                icon = null;
            if(detailDialog!=null){
                detailDialog.dispose();
private Image LoadImageFromDB(String personnr){
        Image img = null;
        String filename = personnr + ".jpg";
        Connection con = getMysqlConnection();
        Statement stmt;
        ResultSet rs;
        try {
            stmt = con.createStatement();
            String query = "select * from personImage where image='"+filename+"'";
            rs=stmt.executeQuery(query);
            if(rs.next()){
                int len=rs.getInt(2);
                byte [] b=new byte[len];
                InputStream in = rs.getBinaryStream(3);
                try {
                    in.read(b);
                    in.close();
                    img =
                            java.awt.Toolkit.getDefaultToolkit().createImage(b);
                } catch (IOException e) {
                    e.printStackTrace();
            rs.close();
            rs = null;
            stmt.close();
            stmt = null;
            con.close();
            con = null;
        } catch (SQLException e) {
            e.printStackTrace();
        return img;
public void random(){
        java.sql.ResultSet rs = null;
        java.sql.Statement stmt=null;
        java.sql.Connection con = getSybaseConnection();
        try {
            try {
                stmt = con.createStatement();
                rs = stmt.executeQuery(randomquery);
                while(rs.next()){
                    Person person = new Person();
                    person.number = rs.getString("PersonNr");
                    Image img = LoadImageFromDB(person.number);
                    if(img !=null){
                        MyImageIcon ico = new MyImageIcon(img);
                        person.icon = ico;
                    person.detailDialog = new
                            DetailDialog(person.number,person.icon);
                    personList.add(person);
                    System.out.println("Container size: " +
                            personList.size());
                    counter++;
                if(counter%20 == 0){
                    for(Person p : personList){
                        p.destroy();
                    personList.clear();
                    System.gc();//no need, but I force for this example
                    System.out.println("Container cleared, size: " +
                            personList.size());
            } catch (SQLException ex) {
                ex.printStackTrace();
            }finally{
                if(rs != null){
                    rs.close();
                }if(stmt != null){
                    stmt.close();
                }if(con != null){
                    con.close();
        } catch (SQLException ex) {
            ex.printStackTrace();
    }