Thread Safety: Invalid Tread Access

Hello everyone, I'm somewhat stuck in a rut and would appreciate any advice I could get on this problem I'm having. It's a relatively large system but I'll try and be succinct.
There are two classes in question.
The first one buids an (SWT) interface, this interface contains a Tree object.
The second class (traverses a parse tree and) needs to add a TreeItem to the Tree in the first class.
public class SomeApp extends ApplicationWindow {
     private static Tree tree;
     private Composite composite;
     public SomeApp(Shell parentShell)
          super(parentShell);
                 addMenuBar();
                  addStatusLine();
                addToolBar(SWT.FLAT);
     public static void main(String[] args) {
          ApplicationWindow viewer = new SomeApp(null);
                  viewer.setBlockOnOpen(true);
                   viewer.open();
     protected Control createContents(Composite parent) {
          getShell().setText("An Application");
          setStatus("Ready");
          composite = new Composite(getShell(), SWT.NONE);
          tree = new Tree(composite, SWT.NONE);
                try {
                        AnotherClass someClass = new AnotherClass()
               someClass.addTreeItem()
          } catch (Exception e) {
               System.out.println("Error: "+e.getMessage());
          return composite;
public class AnotherClass
public AnotherClass(){};
       public void addTreeItem() {
              try {
                    TreeItem ti = new TreeItem(SomeApp.tree,0);
                    ti.setText("Any old text");
              catch (Exception e) {
               System.out.println("Error2: "+e.getMessage());
          }"Error2: Invalid thread access" is the error message being spat out.
If anyone could point out which methods/objects need to be static and/or code needs to be synchronised, or any way to make the class/object thread safe I'd be extremely greatful thanks.

I've resolved this issue thanks.
"Applications that wish to call UI code from a non-UI thread must provide a Runnable that calls the UI code."
http://help.eclipse.org/help31/index.jsp?topic=/org.eclipse.platform.doc.isv/guide/swt_threading.htm

Similar Messages

Vector Replacement in Java 1.4 - Is Thread Safety Needed In This Scenario?

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The several instances of the application are all independent JVMs and can't interact with each other directly at all. So there's no thread safety issue there and there never was. So what does that leave you? You've got a single worker thread using the Vector? There's no thread safety issue there either. The only time you have to think about thread safety is when two threads are trying to use the same object.

Java Bean Thread Safety

I've been using JavaBeans for years now, and have read at least 30 different texts and online resources about using Java beans in JSPs. But in every single one of them, they are ambiguous and non-committal about how to properly use them to avoid Thread-Safety problems in a multithreaded (web server) environment. Are there any true Java gurus out there who know how to do so in JSPs?
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I ask because in many texts, they make a vague suggestion "be sure to write your beans thread-safe"--but provide no concrete answer as to how (the level at which to declare 'synchronized'). But in all their code examples, I have never once, in all these years, seen the word "synchronized".
How is this possible? Wouldn't the bean, as bound to the thread-shared pageContext object, be completely exposed to thread corruption, with multiple threads simultaneously calling its methods?
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PageContext is shared by many threads?
Not at one time, I'm pretty certain of that.
From the API: A PageContext instance is obtained by a JSP implementation class by calling the JspFactory.getPageContext() method, and is released by calling JspFactory.releasePageContext().
The to me suggests the contract that a PageContext can only be in use by on one JSP page at a time. As far as I am concerned, pageContext can be treated like a "local variable" to a jsp page.
The contents of the pageContext object are maybe a different story, but we'll get to that.
The things to worry about with thread safety are the same as they are for servlets.
1 - Class attributes are not threadsafe. ie variables declared within <%! %> signs
2 - Session attributes are potentially not threadsafe if the user makes two quick requests in a row (handling two requests for the same session)
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THREAD SAFETY ISSUE OF SERVLET

It is possible that one instance of a sevlet is accessed by multiple
client , then how is the concurrency issue taken care of? Especually thread safety?

It's not, you have to handle it yourself.
That's why it's a good idea to never put instance variables in servlets. The basic technique is to store anything you need to save between requests in the current user's session (which you get by calling request.getSession()). During a call to service() (or, more frequently, to doGet or doPost, you're safe if you use whatever is present in the request and response argument, including servlet config parameters, request parameters, request attributes, and session attributes.
If you want to write some "real" servlet app, you should have a look at one of the frameworks, like Jakarta Struts or OpenSymphony WebWorks.

Thread Safety Issue with DOM

I am parsing an XML into a DOM object using the Xerces parser that is packaged with JDK 1.5.
First, I create a new instance of the DocumentBuilderFactory and then using the factory, create a new DocumentBuilder. I then parse the XML using the DocumentBuilder to obtain a DOM object.
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Reflection objects and thread safety

Hi,
I believe that I saw that Field and Method objects are thread-safe (i.e., can safely have methods called against a single object instance concurrently from multiple threads), but am having trouble finding such a description in the JDK javadocs static that fact.
I'm assuming that all thread-specific 'state' would be managed by the Object target passed to methods like invoke()/get()/set() and not on the actual Field and Method objects themselves. Ideally, i'd like to only have to look up fields and methods only once reflectively, and thereafter just use the same reflection object instances to access their target objects at runtime as a performance optimizations - possibly in different threads and at the same time - without having to pay the cost of looking it up again. I should be able to do that providing Method.invoke() is thread safe. Otherwise, i'd probably be forced to call Class.getMethod() to get a new Method object to use against each object instance, which would be more costly both from a memory standpoint (more Method objects) and a lookup-cost perspective.
Given that lots of existing performance-critical enterprise infrastructure code, such as OR database APIs, IoC frameworks and J2EE containers use reflection to decouple the generic code from any app specific code (from a compile time perspective) as an alternative to code generation, it's surprising that there's no obvious statement about thread safety in these classes. If I look at the source code for Method, it appears to be thread safe, but I can only get so far with this analysis, as the critical code in Method appears to be implemented using a class named 'sun.reflect.MethodAccessor', whose source I don't have access to.
I know it's possible to invoke a method against multiple objects by calling Method.invoke() against each of the target objects in question. However, there's no mention as to whether it's safe to use a single Method object instance to invoke a method against multiple target object instances at the same time (i.e., from different threads running in parallel). This would fail, for instance, if the Method object had data members that were used to communicate information between internal calls without any synchronization, as the values might be used by one thread while another was changing them.
Just to clarify (as i've seen some confusion in other forum discussions on this topic):
I completely understand that the thread safety of a target object's method (read, small 'm') is entirely dependent upon it's implementation and not the mechanism by which it's invoked - i.e., whether a method is invoked by an explicit compiled-in call against an instance of the target object in some Java source file, or indirectly via Method object-based reflection, is immaterial the the method's thread safety.
What i'm asking about is the thread safety of the Method.invoke() call itself (read, big 'M'). Same question wrt Field.get()/.set() as well. These calls should be thread-safe if they're stateless wrt the Method and Field object instances that they are invoked against.

In general, if a Java API is silent about multi-threading, it is intended to be thread-safe. See the javadoc for HashMap for an example of an explicit warning.
It is true that Java code can have bugs that show up only on unusual implementations of the Java memory model, such as relaxed memory model machines. Most (if not all) implementations of the JDK have been deployed principally on platforms with strong memory models. (Perhaps not coincidentally, those are also the machines that have market share.) There are even bugs found occasionally in the JDK core, so draw your own conclusions about the bug-tail of our software stack on systems with relaxed memory models!
One of the more likely bugs to run into on highly optimized systems is failure of timely initialization of non-final fields in objects which are shared in an unsynchronized manner. See http://www.cs.umd.edu/~pugh/java/memoryModel/jsr-133-faq.html#finalRight and related pages. JDK core programmers (at Sun, to my personal knowledge) take care not to write code with such bugs, but application programmers might.
And, yes, caching your own Method objects is a good idea, if only because their lookup is generally cumbersome and slow. If you are very performance sensitive, you'll end up generating bytecode "shim" between your callers and the desired target methods. I expect that the http://openjdk.java.net/projects/mlvm/ (an openjdk project we are just starting) will provide some relief for this; stay tuned.
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For more information about method calls, including reflective methods, see my blog post: http://blogs.sun.com/jrose/entry/anatomy_of_a_call_site
Best wishes...

Please Explain SRV.2.3.3.3 Thread Safety

SRV.2.3.3.3 Thread Safety
Implementations of the request and response objects are not guaranteed
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scope of the request handling thread. References to the request and
response objects must not be given to objects executing in other
threads as the resulting behavior may be nondeterministic.
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My question is does a scenario arise often in practice?No, because people are usually smart enough not to access request and response objects from several threads :-)
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Query on thread safety

Hi everybody
i have a query relating to thread safety.When we say that Vector is thread safe or synchronized and Arraylist is not synchronized,what does that really mean.if possible can you provide me with a piece of code to clear the above query.
Also can you tell me in which situations i should use a Vector & Arraylist in my code.
regards
kvikram

i have a query relating to thread safety.When we say
that Vector is thread safe or synchronized and
Arraylist is not synchronized,what does that really
mean.You have two or more theads accessing data. At least one of those is modifying the data. That is the problem.
>
Also can you tell me in which situations i should use
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Thread safety in FMIS

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When you JCD's are started by a JMS message (this is when your JCD's implement the JMS receive web service), you can configure in the connectivity map how many instances of your JCD can be started concurrently by the application server. When double clicking the configuration block on the JMS inbound connection you can specify two options:
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MessageFormat.format - Thread safety - vital question

Hello Forum
This question is especially on the function *"public static String format(String pattern, Object... arguments)"* in Message format class. No information is given in Javadoc for this function regarding thread safety. However a generic message for the entire class is given in the javadoc stating that the - *"Message formats are not synchronized. It is recommended to create separate format instances for each thread. If multiple threads access a format concurrently, it must be synchronized externally."*
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regards
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user10855645 wrote:
Hello Forum
This question is especially on the function *"public static String format(String pattern, Object... arguments)"* in Message format class. No information is given in Javadoc for this function regarding thread safety. However a generic message for the entire class is given in the javadoc stating that the - *"Message formats are not synchronized. It is recommended to create separate format instances for each thread. If multiple threads access a format concurrently, it must be synchronized externally."*Doesn't sound like much of a question. They're not threadsafe, so use separate instances for separate threads, or use appropriate synchronization. Open and shut.
However, if you look at the decompiled source of the function......you're doing it wrong. The implementation is the wrong place to look, and you can't rely on that. Go by the documentation, not by the implementation.
And you're confused as well. The docs for that method say: "Creates a MessageFormat..." So you have your answer right there.
Here no shared object is being accessed, a new object is created within the static method and the same is used for formatting. This decompiled version indicates that this method is actually thread safeWrong. The documentation indicates that it's threadsafe. The deompiled code only tell you what that particular implementation is doing.
I'm not sure what you're concerned or confused about in the first place. The docs for the class say "use a separate instance for each thread," and the docs for that method say, "creates a new instance." So where's the confusion?

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Hi All,
What is Thread Safety in timer jobs on SharePoint?
Thanks in advance!

hi
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Blog - http://sadomovalex.blogspot.com
Dynamic CAML queries via C# - http://camlex.codeplex.com

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The default TopLink implementation for:
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- Set is HashSet
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So if I choose my own implementation do I need a thread safe implementation for?
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java.util.ConcurrentModificationException
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at java.util.AbstractList$Itr.next(AbstractList.java:420)
at oracle.toplink.internal.queryframework.InterfaceContainerPolicy.next(InterfaceContainerPolicy.java:149)
at oracle.toplink.internal.queryframework.ContainerPolicy.next(ContainerPolicy.java:460)
at oracle.toplink.internal.helper.WriteLockManager.traverseRelatedLocks(WriteLockManager.java:140)
at oracle.toplink.internal.helper.WriteLockManager.acquireLockAndRelatedLocks(WriteLockManager.java:116)
at oracle.toplink.internal.helper.WriteLockManager.checkAndLockObject(WriteLockManager.java:349)
at oracle.toplink.internal.helper.WriteLockManager.traverseRelatedLocks(WriteLockManager.java:144)
at oracle.toplink.internal.helper.WriteLockManager.acquireLockAndRelatedLocks(WriteLockManager.java:116)
at oracle.toplink.internal.helper.WriteLockManager.checkAndLockObject(WriteLockManager.java:349)
at oracle.toplink.internal.helper.WriteLockManager.traverseRelatedLocks(WriteLockManager.java:144)
at oracle.toplink.internal.helper.WriteLockManager.acquireLockAndRelatedLocks(WriteLockManager.java:116)
at oracle.toplink.internal.helper.WriteLockManager.acquireLocksForClone(WriteLockManager.java:56)
at oracle.toplink.publicinterface.UnitOfWork.cloneAndRegisterObject(UnitOfWork.java:756)
at oracle.toplink.publicinterface.UnitOfWork.cloneAndRegisterObject(UnitOfWork.java:714)
at oracle.toplink.internal.sessions.UnitOfWorkIdentityMapAccessor.getAndCloneCacheKeyFromParent(UnitOfWorkIdentityMapAccessor.java:153)
at oracle.toplink.internal.sessions.UnitOfWorkIdentityMapAccessor.getFromIdentityMap(UnitOfWorkIdentityMapAccessor.java:99)
at oracle.toplink.internal.sessions.IdentityMapAccessor.getFromIdentityMap(IdentityMapAccessor.java:265)
at oracle.toplink.publicinterface.UnitOfWork.registerExistingObject(UnitOfWork.java:3543)
at oracle.toplink.publicinterface.UnitOfWork.registerExistingObject(UnitOfWork.java:3503)
at oracle.toplink.queryframework.ObjectLevelReadQuery.registerIndividualResult(ObjectLevelReadQuery.java:1812)
at oracle.toplink.internal.descriptors.ObjectBuilder.buildWorkingCopyCloneNormally(ObjectBuilder.java:455)
at oracle.toplink.internal.descriptors.ObjectBuilder.buildObjectInUnitOfWork(ObjectBuilder.java:419)
at oracle.toplink.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:379)
at oracle.toplink.queryframework.ObjectLevelReadQuery.buildObject(ObjectLevelReadQuery.java:455)
at oracle.toplink.queryframework.ObjectLevelReadQuery.conformIndividualResult(ObjectLevelReadQuery.java:622)
at oracle.toplink.queryframework.ReadObjectQuery.conformResult(ReadObjectQuery.java:339)
at oracle.toplink.queryframework.ReadObjectQuery.registerResultInUnitOfWork(ReadObjectQuery.java:604)
at oracle.toplink.queryframework.ReadObjectQuery.executeObjectLevelReadQuery(ReadObjectQuery.java:421)
at oracle.toplink.queryframework.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:811)
at oracle.toplink.queryframework.DatabaseQuery.execute(DatabaseQuery.java:620)
at oracle.toplink.queryframework.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:779)
at oracle.toplink.queryframework.ReadObjectQuery.execute(ReadObjectQuery.java:388)
at oracle.toplink.queryframework.ObjectLevelReadQuery.executeInUnitOfWork(ObjectLevelReadQuery.java:836)
at oracle.toplink.publicinterface.UnitOfWork.internalExecuteQuery(UnitOfWork.java:2604)
at oracle.toplink.publicinterface.Session.executeQuery(Session.java:993)
at oracle.toplink.publicinterface.Session.executeQuery(Session.java:950)

Hi Lionel,
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A good place to start looking for answers is:
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Urgent question about Thread-safety

Hi all,
the new tiger release provides an "isReachable()" method for the "InetAddress" object.
I've found, this method is not thread-safe (see the source and output below).
It returns true for all threads, when multiple threads using this method with different adresses are running at a time and one of the addresses is reachable. This happens only on WinXp. Running on Linux, the output is like expected.
I've tried to report this as a bug. But the gurus answered, taking care of thread safety would be a "programmers task".
My question is, what can I do, to be thread-safe in my case?
W.U.
import java.util.*;
import java.net.*;
public class IsReachableTest_1 extends Thread{
    static volatile int inst=1;
    static final String NET_ADDR="192.168.111.";
    int instance=inst++;
    public void run(){
        for(int i=19;i<23;i++){
            try{
                long start=System.nanoTime();
                if(InetAddress.getByName(NET_ADDR+i).isReachable(1000))
                    System.out.println(""+instance+"--host found at:"+NET_ADDR+i+"--time:"+(System.nanoTime()-start)/1000000);
                else
                    System.out.println(""+instance+"--no host at:"+NET_ADDR+i);
            }catch(Exception e){System.out.println(""+instance+"--ERROR "+e.toString());}
        System.out.println(""+instance+"--done.");
    public static void main(String[] args) {
        System.out.println(
            System.getProperty("java.vendor")+" "+
            System.getProperty("java.version")+" running on "+
            System.getProperty("os.name")+" "+
            System.getProperty("os.version"));
        Vector v=new Vector();
        System.out.println("\nTest 1: One after another:");
        for(int i=0;i<10;i++){
            IsReachableTest_1 t;
            t=new IsReachableTest_1();
            t.start();
            try{
                t.join();
            }catch(Exception e){System.out.println("MAIN1: "+e.toString());}
        System.out.println("\nTest 2: All together:");
        inst=1;
        for(int i=0;i<10;i++){
            IsReachableTest_1 t;
            t=new IsReachableTest_1();
            t.start();
            v.addElement(t);
        for(Iterator i=v.iterator();i.hasNext();)
            try{
                ((IsReachableTest_1)i.next()).join();
            }catch(Exception e){System.out.println("MAIN2: "+e.toString());}
            System.out.println("\nALL DONE");
And here is the output, when running on WinXp:
Sun Microsystems Inc. 1.5.0-beta running on Windows XP 5.1
Test 1: One after another:
1--no host at:192.168.111.19
1--no host at:192.168.111.20
1--host found at:192.168.111.21--time:2
1--no host at:192.168.111.22
1--done.
2--no host at:192.168.111.19
2--no host at:192.168.111.20
2--host found at:192.168.111.21--time:4
2--no host at:192.168.111.22
2--done.
3--no host at:192.168.111.19
3--no host at:192.168.111.20
3--host found at:192.168.111.21--time:1
3--no host at:192.168.111.22
3--done.
4--no host at:192.168.111.19
4--no host at:192.168.111.20
4--host found at:192.168.111.21--time:1
4--no host at:192.168.111.22
4--done.
5--no host at:192.168.111.19
5--no host at:192.168.111.20
5--host found at:192.168.111.21--time:3
5--no host at:192.168.111.22
5--done.
6--no host at:192.168.111.19
6--no host at:192.168.111.20
6--host found at:192.168.111.21--time:1
6--no host at:192.168.111.22
6--done.
7--no host at:192.168.111.19
7--no host at:192.168.111.20
7--host found at:192.168.111.21--time:1
7--no host at:192.168.111.22
7--done.
8--no host at:192.168.111.19
8--no host at:192.168.111.20
8--host found at:192.168.111.21--time:1
8--no host at:192.168.111.22
8--done.
9--no host at:192.168.111.19
9--no host at:192.168.111.20
9--host found at:192.168.111.21--time:1
9--no host at:192.168.111.22
9--done.
10--no host at:192.168.111.19
10--no host at:192.168.111.20
10--host found at:192.168.111.21--time:1
10--no host at:192.168.111.22
10--done.
Test 2: All together:
1--no host at:192.168.111.19
2--no host at:192.168.111.19
3--no host at:192.168.111.19
4--no host at:192.168.111.19
5--no host at:192.168.111.19
6--no host at:192.168.111.19
7--no host at:192.168.111.19
8--no host at:192.168.111.19
9--no host at:192.168.111.19
10--no host at:192.168.111.19
2--no host at:192.168.111.20
3--no host at:192.168.111.20
6--host found at:192.168.111.20--time:924 <----- this host does not exist!!
5--host found at:192.168.111.20--time:961 <----- this host does not exist!!
10--host found at:192.168.111.20--time:778 <----- this host does not exist!!
9--host found at:192.168.111.20--time:815 <----- this host does not exist!!
2--host found at:192.168.111.21--time:37
7--host found at:192.168.111.20--time:888 <----- this host does not exist!!
8--host found at:192.168.111.20--time:852 <----- this host does not exist!!
4--host found at:192.168.111.20--time:997 <----- this host does not exist!!
1--host found at:192.168.111.20--time:1107 <----- this host does not exist!!
3--host found at:192.168.111.21--time:38
6--host found at:192.168.111.21--time:1
5--host found at:192.168.111.21--time:1
10--host found at:192.168.111.21--time:2
2--host found at:192.168.111.22--time:3 <----- this host does not exist!!
9--host found at:192.168.111.21--time:2
7--host found at:192.168.111.21--time:1
4--host found at:192.168.111.21--time:3
1--host found at:192.168.111.21--time:39
2--done.
1--host found at:192.168.111.22--time:5 <----- this host does not exist!!
1--done.
10--host found at:192.168.111.22--time:40 <----- this host does not exist!!
3--host found at:192.168.111.22--time:192 <----- this host does not exist!!
6--host found at:192.168.111.22--time:75 <----- this host does not exist!!
8--host found at:192.168.111.21--time:230
5--host found at:192.168.111.22--time:155 <----- this host does not exist!!
4--host found at:192.168.111.22--time:78 <----- this host does not exist!!
9--host found at:192.168.111.22--time:77 <----- this host does not exist!!
7--host found at:192.168.111.22--time:76 <----- this host does not exist!!
10--done.
6--done.
4--done.
5--done.
3--done.
7--done.
9--done.
8--no host at:192.168.111.22
8--done.
ALL DONE

I created this test (it's basically the same as your class):
import java.util.*;
import java.net.*;
public class IsReachableTest_2 implements Runnable {
    private final String[] addresses = new String[] {
         "www.sun.com",
         "129.42.16.99" // www.ibm.com which is not reachable
    public void run(){
        try {
            for (int i = 0; i < addresses.length; i++) {
                final long start = System.nanoTime();
                final String address = addresses;
     if (InetAddress.getByName(address).isReachable(5000)) {
     System.out.println(Thread.currentThread().getName() + ": Host found at: " + address +
          " --time: " + (System.nanoTime() - start) / 1000);
     } else System.out.println("no host at: " + address);
} catch(Exception e){
e.printStackTrace();
System.out.println("Thread " + Thread.currentThread().getName() + " DONE");
public static void main(String[] args) {
System.out.println(
     System.getProperty("java.vendor") +
     " " +
     System.getProperty("java.version") +
     " running on " +
     System.getProperty("os.name") +
     " " +
     System.getProperty("os.version")
for (int i = 0; i < 10; i++) {
     final Thread t = new Thread(new IsReachableTest_2(), "THREAD " + (i+1));
     t.start();
And I get:
Sun Microsystems Inc. 1.5.0-beta running on Windows 2000 5.0
THREAD 1: Host found at: www.sun.com --time: 217653
THREAD 3: Host found at: www.sun.com --time: 214404
THREAD 6: Host found at: www.sun.com --time: 214900
THREAD 4: Host found at: www.sun.com --time: 215901
THREAD 5: Host found at: www.sun.com --time: 216666
THREAD 10: Host found at: www.sun.com --time: 216620
THREAD 9: Host found at: www.sun.com --time: 217405
THREAD 2: Host found at: www.sun.com --time: 220705
THREAD 7: Host found at: www.sun.com --time: 220845
THREAD 8: Host found at: www.sun.com --time: 221384
no host at: 129.42.16.99
Thread THREAD 4 DONE
no host at: 129.42.16.99
Thread THREAD 6 DONE
no host at: 129.42.16.99
no host at: 129.42.16.99
no host at: 129.42.16.99
no host at: 129.42.16.99
no host at: 129.42.16.99
no host at: 129.42.16.99
no host at: 129.42.16.99
no host at: 129.42.16.99
Thread THREAD 5 DONE
Thread THREAD 10 DONE
Thread THREAD 9 DONE
Thread THREAD 7 DONE
Thread THREAD 3 DONE
Thread THREAD 1 DONE
Thread THREAD 2 DONE
Thread THREAD 8 DONE
HOWEVER: I was getting some strange results every so often. Results like:
Sun Microsystems Inc. 1.5.0-beta running on Windows 2000 5.0
THREAD 3: Host found at: www.sun.com --time: 261132
THREAD 9: Host found at: www.sun.com --time: 264183
THREAD 2: Host found at: www.sun.com --time: 266447
THREAD 6: Host found at: www.sun.com --time: 266596
THREAD 8: Host found at: www.sun.com --time: 267192
THREAD 5: Host found at: www.sun.com --time: 268610
THREAD 4: Host found at: www.sun.com --time: 269849
THREAD 1: Host found at: www.sun.com --time: 280978
THREAD 7: Host found at: www.sun.com --time: 272589
THREAD 10: Host found at: www.sun.com --time: 273162
THREAD 3: Host found at: 129.42.16.99 --time: 13657
Thread THREAD 3 DONE
THREAD 4: Host found at: 129.42.16.99 --time: 4123
THREAD 2: Host found at: 129.42.16.99 --time: 9439
THREAD 5: Host found at: 129.42.16.99 --time: 6681
THREAD 8: Host found at: 129.42.16.99 --time: 7655
THREAD 6: Host found at: 129.42.16.99 --time: 8627
THREAD 9: Host found at: 129.42.16.99 --time: 10586
Thread THREAD 4 DONE
Thread THREAD 2 DONE
Thread THREAD 5 DONE
Thread THREAD 8 DONE
Thread THREAD 6 DONE
Thread THREAD 9 DONE
no host at: 129.42.16.99
Thread THREAD 7 DONE
no host at: 129.42.16.99
no host at: 129.42.16.99
Thread THREAD 10 DONE
Thread THREAD 1 DONE
Usually the first run after I had compiled the class (!?) This isn't a thread safety problem.

Invalid memory access of location error when exporting for iOS

I have been recently been asked to convert a flash application for us on the iPad. When I try to publish the .ipa file I end up with the following error:
Invalid memory access of location 0xceip=0x55492db4
I have no idea what might cause this and my google search of the error message has come up pretty empty. If I remove the document class and republish it works fine so I know it has something to do with my code but I haven't the slightest idea where to start looking so I was hoping someone else had run into a similar error and could point me in the right direction.
thanks so much
-Ryan

I managed to figure this out through laborious guess and check. Just thought I would share the bug in case anyone else ever runs into it.
A third party library I was using wrote try catch statements wrong:
try{
catch(Error:*){
No idea why the original author did it like this, probably meant to write "error:*" and didn't release shift fast enough after the "(" but as you might suspect "Error" is a reserved object name to cannot be declared as a paramenter variable
when replaced with:
try{
catch(error:Error){
the memory access bug went away. What is strange is that the incorrect try/catch statement works just fine when published to swf, air, or android and is only an issue with the iOS converter, and obviously produces a very cryptic error.
I was using CS5.5 so maybe this has been fixed (if not I would suggest making this a compile time error) but just thought I would post my findings.

What is the result of violating the thread safety rule of Swing?

I needs to know what is the outcome of violating the thread safety rule of swing? memory leak? I have seen code violating the rule but still runs fine. Did anyone know?
Thanks

I had violated this rule and sometime it flies and sometimes it does a crash and burn. Most often it can result in a bug seen so rarely that it does not become a concern until the day of product roll-out. Mostly it can result in intermitent GUI anomallies and sometimes total app locks that are hard to intentionally reproduce. All paints and updates are done on the event queue and it is possible to invoke a thread on it saftly.
I refer you to the tutorial at: http://java.sun.com/docs/books/tutorial/uiswing/mini/threads.html

Thread Safety: Invalid Tread Access

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