Memory leak with multi-threaded environment
When starting an environment with the THREADED_MUTEXED
or THREADED_UNMUTEXED mode parameter, the oracle OCCI API
has a memory leak. This can be demonstrated by modifying
the "occidml.cpp" demo program as follows:
Replace line 26:
env = Environment::createEnvironment (Environment::DEFAULT);
with
env = Environment::createEnvironment (Environment::THREADED_MUTEXED);
And replace line 164:
demo->displayAllRows();
with
for (int ii=0; ii<10000; ii++) demo->displayAllRows();
Recompile and run the program, and use "top" to see the
size of the process's used memory continually increase
unbounded.
I am using the Oracle 9.2.0.1.0 database on Linux,
gcc version 2.96.
Is anyone aware of a fix for this problem?
Yeah, I did suffer from this.
If possible , you can switch to using OCCI on Oracle 10G client , you will find no memory leak issue anymore.
Another issue is that OCCI is using default connection-blocking implementation , if a DB connection is blocked by accident just like plugging out the network link, you can not get any timeout or connection closed indications. You must implement your own OCCI connection timeout strategy, and you must kill the thread/process you are using.
Similar Messages
-
Memory leaks and multi threading issues in managed client.
In our company we use a lot of Oracle, and after the release of the managed provider we migrated all applications to it. First the things were very impressive : the new client was faster, but after some days applications that uses 100MB with old client goes to 1GB and up. The memory is not the only issue, we use a lot of multi threading, and we experience connection drops and not disposal, after 1 days working one of the application had over 100 sessions on the server. I think there is something wrong with connection pool and multi threading.
Is someone experience same problems.
Yesterday we went back with unmanaged provider. Now things are back to normal.connection drops: did you try to use "Validate Connection=true" parameter in your connection string?
the new client was faster: are you sure with this statement? Even in 64bit environment? I got quite serious performance problems when running application under 64bit process: https://forums.oracle.com/thread/2595323 -
Static methods in multi-thread environment.
Sorry for this silly question, but I have no clue...
If you're using classes with static methods in a application server environment, would that imply all threads use that same 'one in the jvm' method and would there be a possibility for performance loss?
Is calling another static method from a static method a good idea in a multi-thread environment, with respect to performance? Somehow I seem to get this java.lang.NoClassDefFoundError. Any ideas? The classes are in the same package. I only get these kind of problems calling static methods from static methods in a multi-thread environmnent. The static methods are pure utility functions and of course do not use class state.
Thanks for your help.Sorry for this question, wasn't thinking straight. I have the answer, won't post question on multiple forums.
-
Multiple Containers read/write access in multi-threaded environment
I'm been reading the Berkeley DB XML Transaction Processing document and have a few questions. I have a multi-threaded environment (not multi-process).
1) In the "Summary and Examples" section, there is an example of several worker threads that perform many writes to a shared container. The one container is passed to all the worker threads, rather them having their own instance of the container. In my application, I could potentially have multiple worker threads acting on the same container, is it better to provide some type of connection pool, so each thread has access to the same container? Is their a problem with each thread creating a new instance of the container and writing to that? Is their pros and cons to each approach?
2) In some specific web applications, they only require read-access and have no intention of writing to the database. If the environment was created with transactions, can these applications open the environment in read-only mode, so as to not suffer the performance penalty of using transactions? Or do they still require transaction support since other threads in other applications might be writing to it. Is it better in this case to
3) Is there any decent connection pooling framework that work well with BDB XML? If transactions are involved, it seems pretty important to always close the container once you are finished with it, which kind of defeats the purpose of pooling. I see a container somewhat analogous to a JDBC transaction, where in connection pooling these transactions remain open, but in BDB XML, it doesn't seem like this is good practice. So clarification here would be appreciated.
Thanks in advance...
ChrisChris,
I'd be careful about trying to draw too many analogies with other sorts of systems. In many ways BDB XML is simpler -- it's just a library, no server process.
An open container is analogous to an open file handle/descriptor in your operating system. It can safely be shared by all threads within a given process. In fact, you should not create more than one -- while that works, it can just be confusing, and a source of errors (for example, if you use a different path to open the container each time, you'll have problems). So by all means share them. Most Java applications just point them in a class that is accessible to all threads.
Other objects that can, and should be shared among threads include:
Environment
XmlManager
XmlQueryExpression
Most others should not. You also mention closing your containers -- there is no reason to close your active container objects until your application needs to shut down. A long-running application will want to use db_checkpoint (or equivalent) to ensure that modified pages are flushed from the transaction log to the database files, but that's about it.
As for concurrency, you obviously need transactions for concurrent write operations. If you want concurrent read access to the same containers, they should use transactions as well. Even if you don't explicitly use transactions, locks are always taken on pages in transactional containers. You cannot open the same container transactionally and not transactionally at the same time -- bad things could happen.
Depending on your performance needs, you could using snapshot concurrency, and see how it works for you. While locking does incur some overhead, it may be acceptable.
You mention creating your own "snapshot" of a container and running read-only on that copy. That's possible to do, but you have to be careful of how you create the snapshot (following hot backup procedures). Also, if you intend to open that "new" container in the same environment or application as the old one, you need to run a program on it to change its internal identification so Berkeley DB won't think it's the same file. That is, you can't just copy a container file to a new name and just open it like it's a new container if it's still in the vicinity of the original. See the -r option for the db_load program.
Now that you are probably really confused, good luck!
Regards,
George -
Memory leaks with Third party classes
Hello all,
This is fairly known problem. But I guess, my problem gives a new dimention to the problem.
I have an application which is developed by me. This application ideally needed to use third party classes ( obviously no source code is supplied ). These third party classes provide extra functionality required.
The problem is, when I don't use third party classes in my application, every thing is fine. When I include third party classes, I am having memory leaks.
Then I tried to investigate memory leaks with Optimizeit tool. It is new to me. As of now, I understood, we can identify where the memory leaks are occuring.
finally the problem is, in order to solve this, I need some patches in the code. But I don't have source code for those classes. How to solve this problem?
For example,
I use a third party classes in my code like this,
ThirdPartyMemoryLeakClass obj = new ThirdPartyMemoryLeakClass();
This 'obj' is made static, as it takes lot of time to create this object. Obviously this object contains several references to other objects, which I can't control.
In the process of reusing this object, I am getting memory leaks.
Any ideas regarding, how one has to deal this type of situations? What are the issues involved with this case? Are there any similar problems, which have been solved? are most welcome.
many thanks for your time.
MadhavDecompile it using jad. Find leak.Yes, I too got the idea and tried to decompile those classes and recompile. I had some problems while recompiling. Is this is the only way to get rid of this problem?
I was refering to powersoft.datawindow.DataStore class. Does any body here has worked on these?
Can you suggest me how to find the memory leak causes? if you were needed to find out memory leak causes, what would be your approach?
Madhav -
Memory leak with 1.6.0_07 in applet using Swing
Java Plug-in 1.6.0_07
Using JRE version 1.6.0_07 Java HotSpot(TM) Client VM
Windows XP - SP2
I have a commercial application that has developed a memory leak with the introduction of the latest plugin. The applets chew up memory and eventually freeze. They did not before. Using jvisualm I see a build up of native arrays, primarily int[][] and char[]. I'm still investigating. Anyone have a similar experience?
The Applet uses a swing interface, uses buffered images and swing timers, and regularly performs http connections to the server which result in actions via the SwingUtil.invokeLater() method.I am Using Internet Explorer Browser Version 6.0.Huge security hole.
Its not throwing Error / Exception Wrap a try/catch at the highest level possible.
Catch 'Throwable'. And log/display it somewhere. -
Memory leak with UI automation
Hi,
I noticed there is memory leak with UI automation in my window 8.1.
I noticed there is solution for window 8
http://support.microsoft.com/kb/2885482
Is there any solution for window 8.1?
I really appreciate for any help.Hi,
I'm sorry for didn't hear anything about this issue. I'll try to connect the writer of this KB, hope we can find some suggestion. If there is any progress about this problem, I would come back.
Roger Lu
TechNet Community Support -
It seems there is a memory leak with JPopupMenu. The following program demonstrates this leak. If you run the program, click on show form, and then close the form, the used memory will be GCd appropriately. If you click on show form, then right click on the table to show the popup (even if you dont do anything else with the popup) then close the form, it never GCs the form. I've tried all kinds of crazy things, but I cant seem to find what is keeping the memory from being GCd.
Peter
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.beans.PropertyChangeListener;
import java.text.DecimalFormat;
import java.util.Timer;
import java.util.TimerTask;
import java.util.Vector;
import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JRadioButtonMenuItem;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.AbstractTableModel;
@SuppressWarnings("serial")
public class TriState extends JPanel {
private static final long K = 1024;
private static final long M = K * K;
private static final long G = M * K;
private static final long T = G * K;
protected static int ctr = 1;
private JButton btnShow = new JButton("Show Form");
private JLabel lblMem = new JLabel();
private static final DecimalFormat df = new DecimalFormat("#,##0.#");
protected Timer updateTimer = new Timer();
public TriState() {
this.setLayout(new GridLayout());
add(btnShow);
add(lblMem);
updateTimer.scheduleAtFixedRate(new UpdateTimerTask(), 1000, 1000);
btnShow.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
FrmReferrals fr = new FrmReferrals();
fr.setVisible(true);
class UpdateTimerTask extends TimerTask {
public void run() {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
dumpMemoryUsage();
protected void dumpMemoryUsage() {
System.gc();
Long t = Runtime.getRuntime().totalMemory();
long f = Runtime.getRuntime().freeMemory();
String st = convertToStringRepresentation(t);
String sf = convertToStringRepresentation(f);
String su = convertToStringRepresentation(t - f);
System.out.println("Total:" + st + "(" + t + ") Free:" + sf + "(" + f + ") Used:" + su + "(" + (t - f) + ")");
lblMem.setText(su + "/" + st);
public static String convertToStringRepresentation(final long value) {
final long[] dividers = new long[]{T, G, M, K, 1};
final String[] units = new String[]{"TB", "GB", "MB", "KB", "B"};
if (value < 1)
throw new IllegalArgumentException("Invalid file size: " + value);
String result = null;
for (int i = 0; i < dividers.length; i++) {
final long divider = dividers;
if (value >= divider) {
final double dr = divider > 1 ? (double) value / (double) divider : (double) value;
result = df.format(dr) + units[i];
break;
return result;
private static void createAndShowGUI() {
JFrame frame = new JFrame("SimpleTableDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Create and set up the content pane.
TriState newContentPane = new TriState();
newContentPane.setOpaque(true); // content panes must be opaque
frame.setContentPane(newContentPane);
// Display the window.
frame.pack();
frame.setVisible(true);
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
protected class PopupMenu extends JPopupMenu {
public PopupMenu() {
JRadioButtonMenuItem item1 = new JRadioButtonMenuItem(new AbstractAction("Insert Item") {
@Override
public void actionPerformed(ActionEvent e) {
System.out.println(e.getActionCommand());
item1.setActionCommand("Insert");
add(item1);
JRadioButtonMenuItem item2 = new JRadioButtonMenuItem(new AbstractAction("Delete Item") {
@Override
public void actionPerformed(ActionEvent e) {
System.out.println(e.getActionCommand());
item2.setActionCommand("Delete");
add(item2);
public class FrmReferrals extends JFrame {
public FrmReferrals() {
super();
init();
protected void init() {
jbInit();
protected void closeIt() {
uninit();
// variables here
protected Dimension dimPreferred = new Dimension(1270, 995);
protected JTabbedPane tabbedPane = new JTabbedPane();
protected JTable tblReferrals = null;
protected PopupMenu popMenu = new PopupMenu();
protected void jbInit() {
setPreferredSize(dimPreferred);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setTitle("Referrals");
JPanel pnl = new JPanel();
pnl.setOpaque(false);
pnl.setLayout(new BorderLayout());
pnl.add(tabbedPane, BorderLayout.CENTER);
// put it all in the frame
add(pnl);
pack();
setLocationRelativeTo(null);
// init the table and model
ReferralsTableModel ctm = new ReferralsTableModel(buildDummyVector());
tblReferrals = new JTable(ctm);
tblReferrals.setComponentPopupMenu(popMenu);
tblReferrals.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
tabbedPane.add(new JScrollPane(tblReferrals, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED));
addWindowListener(new WindowListener() {
@Override
public void windowActivated(WindowEvent e) {}
@Override
public void windowClosed(WindowEvent e) {}
@Override
public void windowClosing(WindowEvent e) {
closeIt();
@Override
public void windowDeactivated(WindowEvent e) {}
@Override
public void windowDeiconified(WindowEvent e) {}
@Override
public void windowIconified(WindowEvent e) {}
@Override
public void windowOpened(WindowEvent e) {}
protected Vector<DBO_Referrals> buildDummyVector() {
Vector<DBO_Referrals> vr = new Vector<DBO_Referrals>();
for (int x = 0; x < 5000; x++) {
DBO_Referrals r = new DBO_Referrals(x+(5000*ctr));
vr.add(r);
return vr;
protected void uninit() {
tblReferrals.setComponentPopupMenu(null);
for (Component c : popMenu.getComponents()) {
PropertyChangeListener[] pl = c.getPropertyChangeListeners();
for (PropertyChangeListener l : pl)
c.removePropertyChangeListener(l);
if (c instanceof JMenuItem) {
ActionListener [] al = ((JMenuItem)c).getActionListeners();
for (ActionListener l : al) {
((JMenuItem)c).removeActionListener(l);
popMenu = null;
protected class DBO_Referrals {
protected long id;
protected String Employee;
protected String Rep;
protected String Asst;
protected String Client;
protected String Dates;
protected String Status;
protected String Home;
public DBO_Referrals(long id) {
this.id = id;
Employee = "Employee" + id;
Rep = "Rep" + id;
Asst = "Asst" + id;
Client = "Client" + id;
Dates = "Dates" + id;
Status = "Status" + id;
Home = "Home" + id;
public long getId() {
return id;
public String getEmployee() {
return Employee;
public String getRep() {
return Rep;
public String getAsst() {
return Asst;
public String getClient() {
return Client;
public String getDates() {
return Dates;
public String getStatus() {
return Status;
public String getHome() {
return Home;
public class ReferralsTableModel extends AbstractTableModel {
protected Vector<DBO_Referrals> data = new Vector<DBO_Referrals>();
protected String[] sColumns = {"id", "Employee", "Rep", "Assistant", "Client", "Date", "Status", "Home", "R"};
public ReferralsTableModel() {
super();
public ReferralsTableModel(Vector<DBO_Referrals> data) {
this();
this.data = data;
@SuppressWarnings("unchecked")
@Override
public Class getColumnClass(int col) {
switch (col) {
case 0 :
return Long.class;
default :
return String.class;
@Override
public int getColumnCount() {
return sColumns.length;
@Override
public int getRowCount() {
return data.size();
@Override
public Object getValueAt(int row, int col) {
if (row > data.size())
return null;
DBO_Referrals a = data.get(row);
switch (col) {
case 0 :
return a.getId();
case 1 :
return a.getEmployee();
case 2 :
return a.getRep();
case 3 :
return a.getAsst();
case 4 :
return a.getClient();
case 5 :
return a.getDates();
case 6 :
return a.getStatus();
case 7 :
return a.getHome();
case 8 :
return "+";
default :
return null;BTW instead of continually printing out the memory use a profiler (jvisualvm in the jdk/bin directory -> heapdump -> search on your class -> view in instances -> find nearest GC root).
Looks like BasicPopupMenuUI doesn't remove a reference to the JRootPane immediately. As far as I can see it will be removed when another menu shows.
As a hackish workaround you can try this in you FrmReferrals#uninit():
for(ChangeListener listener : MenuSelectionManager.defaultManager().getChangeListeners()) {
if (listener.getClass().getName().contains("MenuKeyboardHelper")) {
try {
Field field = listener.getClass().getDeclaredField("menuInputMap");
field.setAccessible(true);
field.set(listener, null);
} catch (Exception e) {
// ignored
break;
}Funnily enough though it isn't there when I reduce your code to a SSCCE:
import java.awt.*;
import javax.swing.*;
public class TestBasicPopupMenuUILeak extends JFrame {
public TestBasicPopupMenuUILeak() {
super("Not collected right away");
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(
new JButton(new AbstractAction("Show frame") {
@Override
public void actionPerformed(ActionEvent e) {
EventQueue.invokeLater(new Runnable() {
public void run() {
JLabel label = new JLabel(
"Right click to show popup, then close this frame."
+ "The frame with not be GCed until another (popup) menu is shown.");
JPopupMenu popup = new JPopupMenu(
"Popup");
popup.add("Item");
label.setComponentPopupMenu(popup);
// named differently so you can find it
// easily in your favorite profiler
JFrame frame = new TestBasicPopupMenuUILeak();
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(label);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} -
Hello,
I just found a memory leak in my code caused by the SystemTray, but I don't know if that is me that misused SystemTray (I add a trayIcon, then remove it, then add an another one, and so on). I know how to get around that problem, but I don't know the origin of it (my code, java bug ?). So I made the following code reproducing that leak. If someone can give me idea or advice :-)
class MyThread extends Thread {
ReferenceQueue<?> referenceQueue;
public MyThread(ReferenceQueue<?> referenceQueue) {
this.referenceQueue = referenceQueue;
@Override
public void run() {
System.out.println("Starting ...");
try {
while (true) {
referenceQueue.remove();
System.out.println("We release a TrayIcon");
} catch (InterruptedException ex) {
Logger.getLogger(MyThread.class.getName()).log(Level.SEVERE, null, ex);
class MyPopup extends PopupMenu {
static final int MAX = 1000000;
Integer []toto = new Integer[MAX];
public MyPopup() {
for(int i = 0; i < MAX; i++)
toto[i] = i;
public class Main {
public static void main(String[] args) {
PopupMenu popup;
ReferenceQueue referenceQueue = new ReferenceQueue();
Vector<WeakReference>weakReference = new Vector<WeakReference>();
MyThread myThread = new MyThread(referenceQueue);
myThread.start();
SystemTray tray = SystemTray.getSystemTray();
TrayIcon trayIcon;
File file = new File(<AN IMAGE HERE>);
Image image;
try {
image = ImageIO.read(file);
while(true) {
popup = new PopupMenu();
trayIcon = new TrayIcon(image, "Frame Title", popup);
tray.add(trayIcon);
tray.remove(trayIcon);
weakReference.add(new WeakReference(trayIcon, referenceQueue));
} catch (IOException ex) {
Logger.getLogger(MyJFrame.class.getName()).log(Level.SEVERE, null, ex);
} catch (AWTException e) {
Logger.getLogger(MyJFrame.class.getName()).log(Level.SEVERE, null, e);
}------------------------------------------- ADDED -----------------------------------
P.S. :
- the toto array in MyPopup is there in order to obtain quicker a OutOfMemory (OOM)
- you may change your java parameter by fixing the allowed memory size in order to have a OOM quicker (-Xms30m -Xmx30m)
- you must have an image in order to test this code (and set the path where <AN IMAGE HERE> is)
- if you remove the following lines there is no OOM :
tray.add(trayIcon);
tray.remove(trayIcon);
so it seems to me that TrayIcon is the origin of the OOM
- the weak reference is there in order to see when a trayIcon can be garbage collected
Edited by: lemmel on May 5, 2009 7:22 AM - added commentsSo I did the test and:
- you were right about the vector, but this one was added only for debugging purpose (find the OOM cause)
- your code sample get a OOM with my computer as well as mine (with the vector removed obviously); I made some alteration to your code see below
could you try changing your java memory settings (see below) ?
P.S. :
- I first tried with your code as it was, got the OOM, then decided to give some time to the garbage collector (and later to force a call to it) by adding the lines with the tag ADDED
import java.awt.*;
import java.awt.image.BufferedImage;
static class MyPopup extends PopupMenu {
public static void main(String[] args) throws Exception{
SystemTray tray = SystemTray.getSystemTray();
BufferedImage image = new BufferedImage(16, 16, BufferedImage.TYPE_INT_RGB);
int i = 0; //ADDED
while (true) {
PopupMenu popup = new MyPopup();
TrayIcon newTrayIcon = new TrayIcon(image, "Frame Title", popup);
tray.add(newTrayIcon);
tray.remove(newTrayIcon);
if((i%10)==0) { //ADDED
System.gc(); //ADDED
System.runFinalization(); //ADDED
Thread.sleep(100); //ADDED
} //ADDED
i ++; //ADDED
}I removed the array trick in the MyPopup class in order to be able to do at least one loop (see my settings below)
- my environnement :
---- debian testing, kernel 2.6.26-1-686, libc6 2.9-4
---- tried with both java 6.12 and 6.13 (1.6.0_13; Java HotSpot(TM) Client VM 11.3-b02), use Netbeans NetBeans IDE 6.5 (Build 200811100001)
---- put those flags: -Xms5m -Xmx5m -
Hello all,
Not sure if this is the right place to post this but here goes. I have a program that needs to change the font of at least 250,000 letters, however after doing this the program runs slow and laggy as if changing the fonts of each letter took up memory and never released it? Here is a compilable example, Click the button at the bottom of the window and watch the letter it is currently working on. You will notice that around 200,000 it will begin to not smoothly count up anymore but count in kind of a skipping pattern. This seems to get worse the more you do it and seems to indicate to me that something is using memory and not releasing it. I'm not sure why replacing a letter's font with a new font would cause more memory to be taken up I would think if I was doing it properly it would simply replace the old font with the new one not taking anymore memory then it did before. Here is the example: This program sometimes locks up so be prepared. If someone could maybe point out what is causing this to take up more memory after changing the fonts that would be great and hopefully find a solution :) Thanks in advance.
-neptune692
* To change this template, choose Tools | Templates
* and open the template in the editor.
package paintsurface;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.util.List;
public class PaintSurface implements Runnable, ActionListener {
public static void main(String[] args) {
SwingUtilities.invokeLater(new PaintSurface());
List<StringState> states = new ArrayList<StringState>();
Tableaux tableaux;
Random random = new Random();
Font font = new Font("Arial",Font.PLAIN,15);
// Point mouselocation = new Point(0,0);
static final int WIDTH = 1000;
static final int HEIGHT = 1000;
JFrame frame = new JFrame();
JButton add;
public void run() {
tableaux = new Tableaux();
for (int i=250000; --i>=0;)
addRandom();
frame.add(tableaux, BorderLayout.CENTER);
add = new JButton("Change Font of letters - memory leak?");
add.addActionListener(this);
frame.add(add, BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(WIDTH, HEIGHT);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
public void actionPerformed(ActionEvent e) {
new Thread(new ChangeFonts()).start();
void addRandom() {
tableaux.add(
Character.toString((char)('a'+random.nextInt(26))),
UIManager.getFont("Button.font"),
random.nextInt(WIDTH), random.nextInt(HEIGHT));
//THIS CLASS SEEMS TO HAVE SOME KIND OF MEMORY LEAK I'M NOT SURE?
class ChangeFonts implements Runnable {
public void run() {
Random rand = new Random();
for(int i = 0; i<states.size(); i++) {
font = new Font("Arial",Font.PLAIN,rand.nextInt(50));
states.get(i).font = font;
add.setText("Working on letter - "+i);
class StringState extends Rectangle {
StringState(String str, Font font, int x, int y, int w, int h) {
super(x, y, w, h);
string = str;
this.font = font;
String string;
Font font;
class Tableaux extends JComponent {
Tableaux() {
this.enableEvents(MouseEvent.MOUSE_MOTION_EVENT_MASK);
lagState = createState("Lag", new Font("Arial",Font.BOLD,20), 0, 0);
protected void processMouseMotionEvent(MouseEvent e) {
repaint(lagState);
lagState.setLocation(e.getX(), e.getY());
repaint(lagState);
super.processMouseMotionEvent(e);
StringState lagState;
StringState createState(String str, Font font, int x, int y) {
FontMetrics metrics = getFontMetrics(font);
int w = metrics.stringWidth(str);
int h = metrics.getHeight();
return new StringState(str, font, x, y-metrics.getAscent(), w, h);
public void add(String str, Font font, int x, int y) {
StringState state = createState(str, font, x, y);
states.add(state);
repaint(state);
protected void paintComponent(Graphics g) {
Rectangle clip = g.getClipBounds();
FontMetrics metrics = g.getFontMetrics();
for (StringState state : states) {
if (state.intersects(clip)) {
if (!state.font.equals(g.getFont())) {
g.setFont(state.font);
metrics = g.getFontMetrics();
g.drawString(state.string, state.x, state.y+metrics.getAscent());
if (lagState.intersects(clip)) {
g.setColor(Color.red);
if (!lagState.font.equals(g.getFont())) {
g.setFont(lagState.font);
metrics = g.getFontMetrics();
g.drawString("Lag", lagState.x, lagState.y+metrics.getAscent());
}Here is the block of code that I think is causing the problem:
//THIS CLASS SEEMS TO HAVE SOME KIND OF MEMORY LEAK I'M NOT SURE?
class ChangeFonts implements Runnable {
public void run() {
Random rand = new Random();
for(int i = 0; i<states.size(); i++) {
font = new Font("Arial",Font.PLAIN,rand.nextInt(50));
states.get(i).font = font; // this line seems to cause the problem?
add.setText("Working on letter - "+i);
}neptune692 wrote:
jverd wrote:
You're creating a quarter million distinct Font objects, and obviously you must be hanging on to all of them because each character is having its font set to the newly created object. So if you have 250k chars, you're forcing it to have 250k Font objects.
Since the only difference is that rand.nextInt(50) parameter, just pre-create 50 Font objects with 0..49, stick 'em in the corresponding elements in an array, and use rand.nextInt to select the Font object to use.That does make sense but it does that when the the program is first launched and doesn't lag. But the second and third time you change the letters font it seems to lag so if it wasn't taking up more memory the second time it should perform like it did when it first launched. I don't care to investigate any further. The real problem is almost certainly the quarter million Font objects. It could be that 250k is fine, but by the time you get to 500k, it has to do a lot of GC, and that's where the slow down is coming. You might even be able to make it work better with the code you have just by tweaking the GC parameters at startup, but I wouldn't bother. Fix the code first, and then see if you have issues.
Does creating a new font for each of those letters not replace the old font object? If it didn't use more memory the second and third time I don't think you would see the skipping in the counter and the slowing down of the iterations. So it must be remembering some of the old font objects or am I wrong?Using new always creates a new object. When you do it the second time around, and call letter.setFont(newFont), the old Font object is eligible for GC. That doesn't mean it will be GCed right away though. The JVM can leave them all laying around until it runs out of memory, and then GC some or all of them. -
Hello everyone.
I need some help with a problem we are having with our application. It consists on Servlets, JMS with MDBs, Xml parsing...
Our application dequeues messages from an Oracle Queue and sends xml-text message to a servlet. It also receives xml-text and enqueues objects in an Oracle Queue.
And it also has access to Oracle Database (context tables, etc).
We are doing everything on Tru64 Unix (and our tests on Win 2000) and we are using WebLogic 6.1.
Our problem is that we have found that it seems that the garbage collector is not running well. I mean, with the time our system is degrading. The memory use increases. It seems to be a memory leak.
We have used a testing tool, OptimizeIt, and we have found that there are
objects that are increasing the use of memory. If we use the option 'java -verbose' we find that it seems to be Hash objects (HashMap, Hashtable) which are increasing the use of memory. In our code we are not using any hashtable nor any class that extends from it (we have deleted everyone).
Can it be due to a problem with WebLogic? A problem with JMS, queues, etc? A problem with JNDI?
Could anybody please help us?
Thanks in advanced.Yes, we see that there are some entries of the type:
java/util/Hahstable$Entry
java/util/Hahstable
weblogic/jndi/Environment
This entries keep growing and growing with the time.
We have deleted all the Hashtable, Properties and all the kind of Collection objects. I guess WebLogic is using this objects in order to arrange our application runs.
Am I right? Do you know if we can do anything?
Thank you. -
Memory Leak with Picture Control
Hi all
There is bug with Picture Control
When you insert you picture data in loop into the shift register, memory leak
Can somebody to prevent this bug?
Run attached example and look at Task Manager
Attachments:
Picture Memory Leak Example.vi 24 KBI believe David properly called the cause of this memory consumption.
In reply # 52 of thsi thread,
http://forums.ni.com/ni/board/message?board.id=BreakPoint&message.id=5&jump=true
I posted an example that inserts 130 FP object images in a picture and moves them around (it is a random walk where each object is assigned a letter and the program terminates when all of the letters required to spell out "Hello World" wander into the trap at the bottom.)
A snippet of the code follows.
A) Start with a blank picture
B) Inster all of the images
C) show the updated image.
Other links to LV Picture control examples can be found in this thread.
http://forums.ni.com/ni/board/message?board.id=BreakPoint&message.id=14&jump=true
Ben
Message Edited by Ben on 01-14-2007 08:58 AM
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction
Attachments:
Many_Objects.JPG 24 KB -
Hi,
I am getting a jvm Memory Leak when i try to load and parse XMLs. The version of JDK is 1.4.1_05. Has anyone faced this problem?
Any pointers to this will be very helpful.
Thanks
RajdeepThere is at least one bug associated with xml (although not because of it) which usually makes an appearance in long running applications.
http://forum.java.sun.com/thread.jsp?forum=31&thread=351925
If this is an internal application you could conceivably replace the StringBuffer class yourself to fix this. -
Memory Leak with Tomcat version update 3.2 to 6.0
Hi, I've been trying to update tomcat from 3.2 to 6.0. My issue is that I have a memory leak(s?) that make the web application unusable. Currently in my setup I am using these components:
Tomcat 6.0, sun JDK 1.6.0_01, mssql 2005, Microsoft SQL Server 2005 JDBC Driver 1.2, xalan 2.7.0, log4j 1.0.4 (should be only out of date component)
It is a fairly large application that uses xslt with xalan and java servlets to display web pages. There was no issue with memory leaks before the update from tomcat 3.2, sun jdk 1.4.2 and old xalan and jdbc (for mssql 2000) components.
My question for the community is, where should I be looking for my memory leak. Are there known issues with my setup?
thanks for your help,
MattJust in case someone goes down the same road as me, my problem was actually the one listed on the page below. My threads are not being released after a StandardContext reload. Which I'm not sure if this leak applies to tomcat version <4 or not.
http://opensource.atlassian.com/confluence/spring/pages/viewpage.action?pageId=2669 -
Hi, Performance tool shows that my App has numerious small memory leak(120byte) with the name NSZombie*, such as NSZombienot_Atype, NSZombie_CFString, NSZombie_Pathstore2. What are they? They came from something like UIKit or CoreGraphics so I do not know how to fix them.
Thank you very much.
ffYou probably have zombies enabled either from code, from an environment variable or as a program argument.
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