| Support Q&A
|
If you don't find the answer you are looking for, check the FAQ. If you still can't find the answer, submit a bug.
I downloaded the
installer, and it isn't working, what's wrong?
I ran the Initialize
Database shortcut, but nothing happened?
I scheduled a task
and it was supposed to xxxxxxx, but nothing happened. How do I know if
it even ran?
When I try to modify
the values they revert back immediately. What's wrong?
When I double-click
on the repetition editor or the parameters editor nothing comes up.
What's wrong?
I'm getting an unhelpful
error message when trying to run my class, what should I do?
Where should I put my
classes, in the drop folder or in a folder in the System Classpath?
Can I add the drop
folder to the System Classpath to facilitate easier development?
I re-compiled a class
in the drop folder, but jTask is still running the old version. What's
wrong?
I added a Jar file
to my System Classpath and I'm getting NoClassDefFound errors, what's wrong?
I added a new directory
to my System Classpath and I'm getting NoClassDefFound errors, what's wrong?
Does the drop folder support
Jar files?
The jTask Control Panel
won't start, what's wrong?
Sometimes I start the
jTask Control Panel and get nothing but a blank gray window.
Sometimes I try to change
the status field of a task and I have a textfield rather than a combo-box.
Why does it take
so long to Add/Remove tasks?
I am getting a message
"Could not start the jTask Service". What could be wrong?
I am getting a message
"Could create RMI Registry". What could be wrong?
I needed to stop the jTask
Service temporarily, is this OK?
I tried to export and
got java.io.NotSerializableException, what is wrong?
I noticed I can run multiple
instances of the jTask Control Panel simultaneously, can this corrupt my
data?
I noticed I can run
multiple instances of the jTask Service simultaneously, can this corrupt
my data?
Why is there a "Warning
- Applet window" on any dialog boxes from my programs?
What happens if my
program takes about 5 minutes to run, and it is scheduled to run every
minute?
Sometimes I cannot
gain focus to the control panel after editing the arguments or repetition
parameters, what is going on?
I tried to edit a
field and the contents changed to java.lang.Object@24578b. How can I get
the original contents back?
I'm using a program which
calls a JNI .dll, it worked fine on the command line, why doesn't it work
in jTask
How can I change the default Java VM Heap size, eg, the equivalent of the -Xmx command line argument?
Can I connect to InstantDB
data sources when running classes under jTask?
Can I connect to network
drives when running classes under jTask?
How can I have classes
load at Startup? How can I stop them?
How do the Start
Date/Time and Stop Date/Time fields work?
The jTask service
gives an error when I try to start it, what can I do?
Can I change the location
of the drop folder?
Can I change the port
which jTask uses?
Can the Java classes
I'm running start Threads?
I set the look and feel
to Motif in the control panel, how come I have the Metal look and feel
when I display dialogs?
What are some reasons
my task would generate a "ClassNotFoundException"?
What are some reasons
my task would generate an "IllegalAccessException"?
What are some
reasons my task would generate an "InvocationTargetException"?
Q: I downloaded the installer, and it
isn't working, what's wrong?
A: The installer program has been tested on several different systems,
but occasionally it has been known to fail. If it doesn't work for you,
please verify that the file size is the same as from the download page
(this is the most common problem). Next, close all applications and re-run
the installer, if possible reboot the entire system to free up all available
resources. If this still does not work, please submit a bug
report with as much information about your system as possible, include
the exact file size of the download file and any error messages or error
windows.
If you want to download a version without an installer, click here.
Q: I ran the Initialize Database shortcut,
but nothing happened?
A: The most likely cause is that jTask cannot find the correct Swing
libraries on your system, and therefore cannot display any dialog windows.
If you an earlier version without Swing 1.03 bundled, you must either have
the Swing 1.03 libraries on your system and in your Classpath, or download
and install the jTask distribution with Swing 1.03 bundled. This is the
case with both JDK/JRE 1.1.x and Java2. This may seem confusing since Java2
already has Swing installed, however jTask does not currently run with
this version of Swing, and the Swing 1.03 libraries must be present on
your system.
Q: I scheduled a task and it was supposed
to xxxxxxx, but nothing happened. How do I know if it even ran?
A: By default jTask will append an entry to the log before and after
invoking a class. Check the System.out section in the Control Panel. If
there is no output as expected, double-check in the jTaskStdOut.txt file.
Also check the System.err tab and jTaskStdErr.txt file for any errors jTask
might have encountered while invoking the class. If there is still no output
in either, then its possible that the class ran successfully, but you are
looking in the wrong place for any changes that were expected (e.g., you
are checking C:\File.txt for changes when it's actually D:\File.txt that
was modified). If it still doesn't look like it executed, make sure
that all the information has been entered in the repetition editor panel
-- a common mistake is to leave the weekday field empty, which will disable
the task completely.
Q: When I try to modify the values they
revert back immediately. What's wrong?
A: This usually means the client is no longer in communication with
the back-end application. Try restarting the control panel to fix the problem.
Q: When I double-click on the repetition
editor or the parameters editor nothing comes up. What's wrong?
A: This usually indicates the same problem. Try restarting the control
panel.
Q: I'm getting an unhelpful error message when trying to run my class, what should I do?
A: The best thing to do is to run the class from the command line.
Please keep in mind that jTask will need to be restarted if any Jar files
or directories are added to the System Classpath, so sometimes classes
will run on the command line but fail in jTask. See Classpath Issues.
Q: Where should I put my classes, in the drop folder or in a folder in the System Classpath?
A: You should put classes that are going to be frequently changed in
the drop folder (eg, C:\Program Files\jTask\classes), since classes in
this location are automatically re-loaded every time the class is re-compiled.
Once a class is loaded from the System Classpath, it is cached in the VM
for the duration of the program lifecycle, and you will need to restart
the jTask Service to have this class refreshed. One thing to be aware of,
however, is that the drop folder isn't in the System Classpath, so you
will need to explicitly supply the Classpath to other packages in the drop
folder with the -classpath flag to javac. (ie, javac -classpath "C:\Program
Files\jTask\classes" myclass.java.
Q: Can I add the drop folder to the System Classpath to facilitate easier development?
A: Yes, but you should remove it afterwards, since this will disable
the auto-reload feature of the drop folder the next time the system is
booted. It's recommended to just use the -classpath flag to javac.
If you use a tool such as TextPad, you can
easily manage a seperate compile CLASSPATH.
Q: I re-compiled a class in the drop folder, but jTask is still running the old version. What's wrong?
A: You probably have another version of the class in your System Classpath,
or the drop folder was added to the System Classpath disabling the auto-reload
feature.
Q: I added a Jar file to my System Classpath and I'm getting NoClassDefFound errors, what's wrong?
A: You must restart the jTask Service in order for the changes to the
System Classpath to be recognized. Alternatively, you could unzip
the jar into a folder already on your System Classpath, or to the drop
folder. See Classpath Issues.
Q: I added a new directory to my System Classpath and I'm getting NoClassDefFound errors, what's wrong?
A: You must restart the jTask Service in order for the changes to the
System Classpath to be recognized. Alternatively, you could move
the classes into a folder already on your System Classpath, or to the drop
folder. See Classpath Issues.
Q: Does the drop folder support Jar files?
A: No. You will have to put all Jar files in the System Classpath. Alternatively
you could unzip them into the drop folder.
Q: The jTask Control Panel won't start, what's wrong?
A: Sometimes the jTask Control Panel fails to "bind" to the jTask Service.
Please try to re-start the control panel. If it still does not start after
repeated attempts (known bug), the only fix is to stop/restart the jTask
Service.
Q: Sometimes I start the jTask Control Panel and get nothing but a blank gray window.
A: This is a known bug, please restart the client to fix the problem.
Q: Sometimes I try to change the status field of a task and I have a textfield rather than a combo-box.
A: This is a known bug, please restart the client to fix the problem.
Q: Why does it take so long to Add/Remove tasks?
A: This is related to the time it takes for the jTask Service and control
panel to pass large objects back and forth over TCP/IP. You should
be seeing no more than ten to fifteen seconds on these operations.
If you are running more than 25 or more tasks there are some performance
issues to consider.
Q: I am getting a message "Could not start the jTask Service". What could be wrong?
A: This is a known bug that happens sporadically (but more likely when
system resources are low). It usually occurs when you are starting the
service manually, rather than on system boot. If it persists, its possible
that you are out of disk space on the drive which jTask is running from.
If this doesn't fix the prolem, please submit a bug report.
Q: I am getting a message "Could not create RMI Registry". What could be wrong?
A: This is a known bug that can happen when stopping/restarting the
jTask Service. The only known workarounds are to change
the port used by both the service and control panel, or to reboot the
system.
Q: I needed to stop the jTask Service temporarily, is this OK?
A: Yes, the only thing to note is that any scheduled tasks will miss
their alarms during that time. Also, you will need to shutdown
and restart the jTask Control Panel.
Q: I tried to export and got java.io.NotSerializableException, what is wrong?
A: This is a known bug. The current workaround is to close the jTask
Control Panel and re-start the jTask Service.
Q: I noticed I can run multiple instances of the jTask Control Panel simultaneously, can this corrupt my data?
A: No, there should be no problems with multiple instances of the control
panel. This does not go for the jTask Service, which you should never run
multiple copies of, even if they are on different ports. The database can
get corrupted this way.
Q: I noticed I can run multiple instances of the jTask Service simultaneously, can this corrupt my data?
A: It's possible, so it's definitely not advisable. If this happens
by accident, however, it should be unlikely for any data corruption to
occur. The only way you could safely do this would be to install an additional
copy of jTask (which would use its own database) on the system (and have
it use a different port).
Q: Why is there a "Warning - Applet window" on any dialog boxes from my programs?
A: This is a known bug, we are looking into getting this removed.
Q: What happens if my program takes about 5 minutes to run, and it is scheduled to run every minute?
A: jTask spawns a new thread each time it invokes a class, so therefore
you would have about 5 instances of that task running at any given time.
This should be avoided in some cases because all of the threads could be
accessing a shared resource.
Q: Sometimes I cannot gain focus to the control panel after editing the arguments or repetition parameters, what is going on?
A: There is a bug which occurs when you switch to a different window
while editing a field in the parameters editor. Please minimize the
last few windows you used and the window in question will re-appear.
Q: I'm using a program which calls a JNI .dll, it worked fine on the command line, why doesn't it work in jTask
A: If you are running jTask as an NT Service, you will need to reboot
the machine to have the service regognize any new .dll's in the WinNT\System32
directory. If jTask is configured to run as a background application, it
should only be necessary to stop/restart jTask.
Q: How can I change the default Java VM Heap size, eg, the equivalent of the -Xmx command line argument?
A: To change the maximum heap size to 128MB, add the following line anywhere in the jTastService.lax file and restart the jTask Service:
lax.nl.java.option.java.heap.size.max=128000000
The size must be specified in bytes, not in kilobytes or megabytes. Similarly, you may set the initial heap size with the lax.nl.java.option.java.heap.size.initial property.
Q: I tried to edit a field and the contents changed to java.lang.Object@24578b. How can I get the original contents back?
A: The short answer is, you can't. This is a known bug. The best way
to avoid this is to wait until the table is finished refreshing before
trying to edit other rows.
Q: Can I connect to InstantDB data sources when running classes under jTask?
A: Not at this time, as doing so will cause a java.sql.SQLException:
Tried to open different database error message, and from that point
on any changes made in the control panel will go un-saved. The jTask Service
will need to be re-started to resume normal operation. Currently the only
safe way to connect to an InstantDB database is to spawn another VM using
the Exec class (see Exec.java in the classes directory).
Q: Can I connect to network drives when running classes under jTask?
A: Due to security limitations on Services running as the System user,
trying to open network drives mapped by letter will not work. The only
way to do it is (possibly) by UNC share name. This has not been tested
and there is no documentation for it Alternatively, you can run the jTask
Service under a user account, but you will lose the ability to display
GUI elements, as well as the ability for jTask to run while nobody is
logged into the machine. There is a utility called ServiceMill from ActivePlus
which will allow User Account Services to interact with the desktop.
Q: How can I have classes load at Startup? How can I stop them?
A: Add a new task as normal, however change the status field to "Startup".
Whenever the jTask Service is started, it will invoke this class. See the
ThreadViewer for information
on stopping invoked classes.
Q: How do the Start Date/Time Filter and Stop Date/Time Filter fields work?
A: Contrary to what you might think, these fields will not cause
a task to be started/stopped at a specific point in time. Instead, they
act as simple filters on the repetition pattern. For example, you are monitoring
a webserver that has been taken offline until Midnight September 1st. Instead
of disabling/deleting the task or editing its repetition pattern, you can
simply put in 9-1-2000 00:00:00 for the Start Date/Time Filter, and the
task won't be executed until (but not necessarily on) that date/time. Similarly,
if you are sending out a daily newsletter to a client whose subscription
expires at Midnight on March 1st, 2002, you can simply put in 3-1-2002
00:00:00 for the Stop Date/Time Filter.
Q: The jTask service gives an error when I try to start it, what can I do?
A: Try changing the port (sometimes the RMI
Registry fails to un-bind), if that doesn't work try rebooting the machine.
Q: Can I change the location of the drop folder?
A: Unfortunately this isn't possible yet.
Q: Can I change the port which jTask uses?
A: Yes, change the net.rmi.port port parameters in "jTaskService.lax"
and "jTask Control Panel.lax"
Q: Can the Java classes I'm running start Threads?
A: Yes, the only things that aren't allowed are calling System.exit()
and loading another SecurityManager.
Q: I set the look and feel to Motif in the control panel, how come I have the Metal look and feel when I display dialogs?
A: You have to manually set the look and feel in your code, see Tips
and Tricks on how to do this.
Q: What are some reasons my task would generate a "ClassNotFoundException"?
A: This means jTask cannot find the class you are trying to run (this
does NOT mean the VM cannot find classes referenced by your class, that
will give you an InvocationTargetException - see below). Please see the
above sections on the System Classpath and the Classpath Issues.
Q: What are some reasons my task would generate an "IllegalAccessException"? I didn't get this error from the command line.
A: This can occur if the class you are trying to run (the one whose
main() method is being invoked) is not declared public.
Q: What are some reasons my task would generate an "InvocationTargetException"? I was able to run the class from the command line, so what could the problem be?
A: This usually means that jTask was both able to find your class and
invoke the main() method, however it encountered a critical exception which
prevented the class from running successfully.
This message will also show up when you manually kill a thread using the ThreadViewer.
The most common reason for this error is an exception occurs outside any try/catch blocks, and so the error message gets lost along the way, resulting in the generalized "InvocationTargetException" error. Another thing to keep in mind is that System.exit() has no effect, so the VM will not break out of the program flow when this is called. If you need to do this, use the "return" statement.
Another very likely cause to this problem is that the VM cannot find a library or class referenced in the class in question. Unfortunately jTask cannot recognize new additions to the System Classpath after it has been started, so if you added a Jar file to your Classpath you will need to restart jTask to see these classes. Alternatively, you can add the class(es) to the special drop folder without having to restart the jTask Service. Since Jar files are not supported in the drop folder, you will have to unzip them. If you are certain that jTask has access to all relevant libraries and you are still getting this error, try putting try/catch blocks around the code (all of it if necessary) and getting a more informative error message. For example:
try {
...
}
catch (Exception e) {
e.printStackTrace();
}