Thread: Problems with people opening documents concurrently in java based document viewer

I am testing a document management system that uses Java to display documents in a special viewer application. We have encountered a strange issue where if multiple people attempt to view/open documents at the same time, the documents do not open and the viewer exhibits various strange behaviour:

1. Displaying Java security warnings - "Java has discovered application components that could indicate a security concern" - Then even if the "No" option is cliked on this dialogue, the document still does not open in the viewer: instead it displays an "Error.Click for details" link in the viewer window. Upon clicking the link, these error details display in a java console window like this:

Java Plug-in 1.6.0_26
Using JRE version 1.6.0_26-b03 Java HotSpot(TM) Client VM
User home directory = C:\Documents and Settings\
----------------------------------------------------
c: clear console window
f: finalize objects on finalization queue
g: garbage collect
h: display this help message
l: dump classloader list
m: print memory usage
o: trigger logging
q: hide console
r: reload policy configuration
s: dump system and deployment properties
t: dump thread list
v: dump thread stack
x: clear classloader cache
0-5: set trace level to <n>
----------------------------------------------------

java.lang.SecurityException: class "com.xyzcorp.test.applet.test" does not match trust level of other classes in the same package
at com.sun.deploy.security.CPCallbackHandler$ChildEle ment.checkResource(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.checkResourc e(Unknown Source)
at sun.plugin2.applet.Applet2ClassLoader.findClass(Un known Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(U nknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Un known Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Un known Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Unk nown Source)
at sun.plugin2.applet.Plugin2Manager.createApplet(Unk nown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionR unnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Exception: java.lang.SecurityException: class "com.docviewerapplication.test.applet.docviewerapp lication" does not match trust level of other classes in the same package


2. The viewer simply doesn't open the document, and just displays the java icon.


3. The window that the viewer should open in asks if you want to install the latest version of Java. If you accept, it goes through the whole process of uninstalling the current version of java, and reinstalling a new one, then after all this, the document still doesn't open ! However, simply shutting down the browser and reopening seems to stop this particular facet of the problem from occuring, at least for a while anyway.


A workaround for these problems has been found where changing the "Mixed code (sandboxed vs. trusted) security verification" option to "Disabe verification (not reccomended)" in the advanced options tab in the java control panel on the client PC you are opening the documents from really seems to reduce or stop these problems from occuring. However, obviously this is not a long term solution when real people will be using the system, and we still get errors (different ones) when 2 or more people try and open documents at the same time, allbeit not as frequently with the java option described above changed.

Any help / advice would be hugely appreciated, we have been stressing about this problem for months now,

Thankyou,

Tim