java-programmer >>Finding memory leak in big app

Finding memory leak in big app

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Author

Message

Big D

Posted: 2003-12-13 4:38:00

Top

java-programmer, Finding memory leak in big app I have an application that uses a lot of memory (up to a gig) and I'm
trying to track a memory leak. The problem is that all of the tools I've
found can't handle such large heap sizes. They generally just run out of
memory themselves.

The bulk of the memory is taken up by double[] and char[], but I need to
know who owns these arrays so I can see why there are so many of them. Is
there any tool that will let me track object ownership, or just give me a
useful heap dump that I can parse myself?

I'm running this on red hat advanced server 4 proc/8gig ram.

I can work with any jdk that's version 1.4.0_01 or higher.

Thanks

Jose Rubio

Posted: 2003-12-13 12:04:00

Top

java-programmer >> Finding memory leak in big app Have you taken a look at JProbe? http://www.quest.com/jprobe/

Jose

"Big D" <email***@***.com> wrote in message
news:email***@***.com...
> I have an application that uses a lot of memory (up to a gig) and I'm
> trying to track a memory leak. The problem is that all of the tools I've
> found can't handle such large heap sizes. They generally just run out of
> memory themselves.
>
> The bulk of the memory is taken up by double[] and char[], but I need to
> know who owns these arrays so I can see why there are so many of them. Is
> there any tool that will let me track object ownership, or just give me a
> useful heap dump that I can parse myself?
>
> I'm running this on red hat advanced server 4 proc/8gig ram.
>
> I can work with any jdk that's version 1.4.0_01 or higher.
>
> Thanks

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    value is lowered for 256
    why?
    
    did I missed something?
- 9
  - coordinating eventsHi there,
    
    I'm having difficulty trying to coordinate the sequence of events for
    populating a JTree with data received from a server app. I'm so-o-o-o close
    and yet no banana! It's proving to be very tricky processing. I could use
    some help in trying to make this work properly. Perhaps you may understand
    better as to why my efforts are being thwarted by the either the JTree
    object or its DefaultTreeModel?
    
    Here's the setup:
    
    1) I have a server app that, when requested from the client app, will
    provide a child count on any given directory node on the server. Also, it
    will serve up the names of each child node for any given node upon request.
    
    2) The client app contains a JTree object that I'm trying to initially
    populate with the root node. Subsequently, the plan is to dynamically
    populate any directory node in the JTree whenever the treeWillExpand( ... )
    event is triggered as the user tries to expand on a node.
    
    3) Throughout my code I have a number of System.out.println( ... )
    statements so that I can see what sequence of events are taking place as the
    client app makes requests to the server and receives replies back from the
    server. Also, some println(...) statements in some key methods which you'll
    see.
    
    4) The sequence of events is supposed to go like so:
    
    i) root node is created
    ii) as the root node is passed as a parameter when creating the JTree
    object
    the getChildCount( ) method of the root node [type DefaultTreeNode
    extends DefaultMutableTreeNode ]
    is called.
    
    public int getChildCount()
    {
    if (!hasChildren)
    {
    defineChildNodes();
    }
    return(super.getChildCount());
    }
    
    iii) Since the root node initially has no children, getChildCount( )
    then calls the method
    defineChildNodes( ).
    
    protected void defineChildNodes()
    {
    hasChildren = true;
    ref.requestChildCountFromServer(this);
    }
    
    As you can see, defineChildNodes( ) simply sets the flag
    hasChildren to true then
    calls a method requestChildCountFromServer(this) which exists in a
    class called Response
    referred here by the variable "ref". Also in the Response class
    there exists the method
    populateTree( ) which initially created the root node and JTree
    objects:
    
    protected void populateTree(String NodeName)
    {
    //System.out.println("Entering populatTree() method");
    //This could take a while, so change the cursor icon
    //ref.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
    try
    {
    String separator = "";
    if(ref.serverOS.equals("Windows"))
    separator = "\\";
    else
    separator = "/";
    rootNode = new DefaultTreeNode(NodeName, true, separator);
    expandingNode = rootNode;
    String rootPath = getLeadingPath(ref.rootPath);
    rootNode.setLeadingPath(rootPath);
    rootNode.setResponseReference(this);
    jTree1 = new JTree(rootNode);
    jTree1.setRootVisible(true);
    jTree1.setShowsRootHandles(true);
    jTree1.collapseRow(0);
    MouseListener popupListener = new PopupListener(ref);
    jTree1.addMouseListener(popupListener);
    
    //Listen to our own expand/collapse events to keep the labels in
    sync
    jTree1.addTreeWillExpandListener(this);
    
    }
    catch(Exception e){System.out.println("Exception in populateTree()
    method"); e.printStackTrace();return;}
    ....
    ....
    }
    
    iv) The requestChildCountFromServer( ) method then makes a request to
    the server app for
    the child count for the root node.
    
    v) I have a separate thread running that listens for all responses
    from the server
    called ResponseListener. In its run( ) method I have the
    following code:
    
    else if(connected == ref.ref.SENDING_CHILDCOUNT)
    {
    System.out.println("Received message: ReceivingChildCount");
    ref.expandingNode.numChildren = input.readInt();
    //expandingNode.setReceivedChildCount(true);
    ref.ref.imageLabel.setIcon(ref.ref.blank);
    ref.ref.textLabel.setText("");
    }
    
    When the root node was originally created I set a reference to it
    using a variable
    named expandingNode. Here you can see that the root node's
    instance variable
    named numChildren is set to a value read in by the DataInputStream
    object
    named input.
    
    vi) The requestChildCountFromServer( ) method in turn calls another
    method in the
    Response class named RequestChildrenFromServer(String path).
    RequestChildrenFromServer(String path) method requests from the
    server the names
    of all the child nodes for the root node.
    
    vii) ResponseListener then receives a response from the server:
    
    else if(connected == ref.ref.SENDING_TREE_DATA)
    {
    System.out.println("Received message: SendingTreeData");
    ref.expandingNode.TreeDataIncoming = true;
    ref.expandingNode.ReceiveChildrenFromServer(input);
    ref.ref.imageLabel.setIcon(ref.ref.blank);
    ref.ref.textLabel.setText("");
    }
    
    Here you can see that the root nodes method named
    ReceiveChildrenFromServer(input) is then called
    while passing it a reference to the DataInputStream so that the
    method can
    read in the names of the child nodes as they come in over the
    wire.
    
    viii) The root node's method ReceiveChildrenFromServer(input) then
    begins receiving the
    names of each child node, creates a new DefaultTreeNode object
    for each child node
    and adds it to the root node, seen below:
    
    protected void ReceiveChildrenFromServer(DataInputStream input)
    {
    System.out.println("Entering ReceiveChildrenFromServer()");
    
    DefaultTreeNode child = null;
    String name = "";
    try
    {
    
    //ref.ref.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
    //System.out.println("numChildren = " + numChildren);
    int nodeType = 0;//default
    //iterate through each of the children as they come in
    //from the server.
    for(int i = 0; i < numChildren; i++)
    {
    name = input.readUTF(); //get the name
    System.out.println("child node: " + name);
    child = new DefaultTreeNode(name); //create a new
    child node
    
    //determine if this node is a directory
    //or a file. Empty directories are denoted
    //as having (nodeType == -1)
    nodeType = input.readInt();
    //System.out.println("node type: " + nodeType);
    if(nodeType == 0)
    {
    //Since a file is a leaf node
    //we won't be needing to continue
    //reading in nodes for it.
    child.setResponseReference(ref);
    child.setAllowsChildren(false);
    child.setHasChildren(false);
    child.setLeadingPath(getWholeServerPath());
    if(ref.ref.serverOS.equals("Windows"))
    child.setSeparator("\\");
    else
    child.setSeparator("/");
    }
    else if(nodeType == -1)
    {
    child.setResponseReference(ref);
    child.setAllowsChildren(true); //It's an empty
    directory
    child.setHasChildren(false);
    child.setLeadingPath(getWholeServerPath());
    if(ref.ref.serverOS.equals("Windows"))
    child.setSeparator("\\");
    else
    child.setSeparator("/");
    
    }
    else
    {
    child.setResponseReference(ref);
    child.setAllowsChildren(true); //It's a directory
    with child nodes
    child.setHasChildren(true);
    child.setLeadingPath(getWholeServerPath());
    if(ref.ref.serverOS.equals("Windows"))
    child.setSeparator("\\");
    else
    child.setSeparator("/");
    }
    
    this.insert(child,i);
    }//end for loop
    
    //ref.ref.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
    }//end try
    catch(IOException ioe){ioe.printStackTrace();}
    catch(NullPointerException npe){npe.printStackTrace();}
    }//end method
    
    IT IS HERE THAT I RUN INTO PROBLEMS!!!!
    
    All the code you see compiles fine. What I found annoying is that, at
    run-time, the sequence of events were as I depict them here until I start
    reading in the names of the childnodes with the
    ReceiveChildrenFromServer(...) method. While it is going through its for
    loop, mysteriously the method getChildCount( ) is called again, which in
    turn calls defineChildNodes( ), which in turn calls
    requestChildCountFromServer(...), which interrupts the processing of the for
    loop in ReceiveChildrenFromServer(...) . Here is the read out from the
    console to prove it:
    
    ***************************************
    Entering requestChildCountFromServer
    waiting for response...
    checking...
    Received message: ReceivingChildCount
    checking...
    got ChildCount: 26 <<<Root node has 26 child nodes
    Entering RequestChildrenFromServer()
    path is: C:\JavaProjects
    Finished calling server for children
    Received message: SendingTreeData
    Entering ReceiveChildrenFromServer()
    checking for tree data ...
    child node: AssignmentServer <<<<ReceiveChildrenFromServer(...)
    method begins reading in names
    child node: AssignmentSubmitter
    child node: Borland
    child node: ClientServerJTreeProject
    child node: DBJavaBean
    child node: DirAdmin.bak
    Entering requestChildCountFromServer <<<This method is called by
    defineChildNodes( ) which was
    
    called by getChildCount( )
    waiting for response...
    checking...
    checking...
    Node Expanding.
    checking...
    checking...
    got ChildCount: 0 <<< Don't know
    why this is reading zero. It should be 26
    child node: DirectoryAdministratorProject <<<For loop from
    ReceiveChildrenFromServer(...) method
    
    resumes reading in names
    child node: EZSmtp
    child node: Icon Editor
    child node: images
    child node: IniFileProject
    child node: J2exe
    child node: JCalculator
    child node: JGridProject
    child node: JSlideShow
    child node: MSSTextEditorProject
    child node: MySQL_JDBC
    child node: PersonalNetSearchProject
    child node: Print_Preview
    child node: PropertiesFileAccessExample
    child node: Sample_EBusiness
    child node: SharewareProject
    child node: SystemTreeProject
    child node: TestProgram
    child node: Thread_Pooling
    child node: ZeroG
    Received message: ReceivingChildCount
    *****************************************
    
    Ultimately, I wind up with a root node being displayed in the JTree that
    only has maybe five or six child nodes displayed when there should be 26
    child nodes.
    
    For further clarity here are the methods requestChildCountFromServer(...)
    and RequestChildrenFromServer(...):
    
    public void requestChildCountFromServer(DefaultTreeNode node)
    {
    
    System.out.println("Entering requestChildCountFromServer");
    String name = "";
    try
    {
    //ref.ref.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
    
    output.writeInt(ref.PATH);
    output.flush();
    output.writeUTF(node.getWholeServerPath());
    output.flush();
    output.writeInt(ref.REQUEST_CHILD_COUNT);
    output.flush();
    System.out.println("waiting for response...");
    timer1 = new ChildCountTimer(node);
    timer1.start();
    timer1.join();
    System.out.println("got ChildCount: " + node.numChildren);
    if(node.numChildren > 0)
    {
    //NodeExpanding = false; //reset
    RequestChildrenFromServer(node.getWholeServerPath());
    //Set up TreeDataTimer so that we know we have a
    //response from the server.
    timer2 = new TreeDataTimer(node);
    timer2.start();
    timer2.join();
    }
    
    //ref.ref.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
    }
    catch(InterruptedException ie){}
    catch(IOException ioe){ioe.printStackTrace();}
    catch(NullPointerException npe){npe.printStackTrace();}
    }
    
    protected void RequestChildrenFromServer(String path)
    {
    System.out.println("Entering RequestChildrenFromServer()");
    
    //Request Children from server
    try
    {
    //ref.ref.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
    output.writeInt(ref.PATH);
    output.flush();
    System.out.println("path is: " + path);
    output.writeUTF(path);
    output.flush();
    //Sending REQUEST_CHILDREN should cause a response
    //from the server: SENDING_TREE_DATA
    output.writeInt(ref.REQUEST_CHILDREN);
    output.flush();
    
    //ref.ref.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
    
    }
    catch(IOException ioe){ioe.printStackTrace();}
    System.out.println("Finished calling server for children");
    }
    
    I realize this post is rather lengthy, however, I didn't know how else to
    explain my dilemma with this project. If you need more information, just
    ask.
    
    Please advise,
    
    Alan
- 10
  - JSTL & Source Code
    
    JavaScript and CSS programmers have for years, been looking for the
    "holy grail", i.e., the ability to hide source code.
    
    Take at look at www.dice.com, do a job search then view source.....
    nothing there except JSTL noatation per below:
    
    -------------------------- start -------------------------------------
    
    
    
    
    
    
    
    ------------------------ end -----------------------------------------
    
    Was not aware that a fringe benefit of JSTL was the ability to hide
    html source code. How secure is this? Can someone hack it to get the
    html source?
    
    I'm one of those Java/JavaScript/CSS programmers that has created
    graphics with CSS on Web pages and would like to keep the code
    private. I have found a crude way but I like the above better.
    
    Thanks
- 11
  - how to add double key listenerhi,
    i want to catch the key event when SHIFT+TAB are pressed simultaneously
    to shift focus to the previous focusable component. the key event is
    caught on a JComboBox. if somebody knows the code to do so plz post it.
    thanx in advance.
- 12
  - slow axis performance vs JAX-RPC?hi..
    
    i've been mainly using axis framework for webservices becouse it's
    simpler, how ever i was told it's the slowers implementions of them
    all, are there any non-commercial frameworks ? simple to use? (and
    production ready not beta).
- 13
  - How to Fail at Software DevelopmentHello,
    
    The book "How to Fail at Software Develoopment" is about all the
    strange and funny things people do in the name of developing software.
    I worked in software development for over 20 years and found silly
    things that were being done in the name of software development were
    being repeated again and again. As a matter of fact, most things that
    cause software projects to fail are forever being repeated. And you
    can spot the symptoms if you know what to look for.
    
    Most people running software projects don't have much software
    experience, so their inventions are usually not new. They rediscover
    the same mistakes over and over again. It turned out to be a book of
    very funny scenarios--some I lived through, and some were lived
    through by others.
    
    Those who don't know the history of software failure are doomed to
    repeat it. You can find the book on Amazon or wherever.
    
    Arthur Griffith
    "How to Fail at Software Development"
    http://www.anchorpointbooks.com
- 14
  - Certification is a must in MNCs,the comming Future.Certification is a mark of excellence that you carry with you
    everywhere you go.
    
    Integer is a authorised testing center for .Net, Java, J2EE, Testing
    etc..... for the clients like Microsoft, Sun, IBM, Exin, Lotus and
    many more...
    
    We offer certifications on:
    
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    and many more...
    
    For more details Visit: http://www.integerblr.com
    For Registration: http://www.integerblr.com/registration/thomsonprometric.asp
    
    Regards
    Ramesh
- 15
  - difference between endorsed and lib folders?hi..
    
    can somone please explain to me what is the difference between the
    endorsed and lib folders in common folder in tomcat? i tried reading
    the documentation but i couldn't figure it out.