FAQ & Support

Java Web Start is not among the applications in the browser's prompt

You don't have Java Web Start properly installed. The following tips may help you to fix the problem.

  1. Check that you have Java Runtime Environment (JRE) properly installed. You can do it by entering "java -version" at the command line. It should output the installed Java version. If not, install the last release of JRE from Java download page.
  2. If you have a properly functioning JRE, then Java Web Start is not properly configured in your browser and should be associated to automatically open JNLP files. Please see Java Web Start FAQ for instructions on how making your browser recognize JNLP files.


Java: "Application Blocked by Security Settings"

With version 1.7, Java is proposing a completely different signature mechanism to authentificate the publisher of an application.

To allow WingJ to start, open Java configuration > Security tab and either:

  1. add "http://tschaffter.ch" to "Exception Site List" (preferably)
  2. set the security level to medium

To open Java configuration, click on Windows/Linux start menu icon, enter "java" in the search field, and click on "Configure Java".


Java Web Start Launcher complains: "Could not create the Java virtual machine"

Typically these issues are due to the memory settings. Some new Java Runtime Environments have become picky about them and refuse to start. You can try the alternative startup link that has no memory requirements by clicking here, but the maximum amount of memory that WingJ will be allowed to use will be around 200-300 MB only. Additional information about how to allow WingJ to use more memory is available here.


Autostarting Java Web Start applications

By default, Google Chrome downlads the startup JNLP file after clicking on the button "Launch WingJ" and requires an additional click on this file to run our application. To start automatically WingJ, Right-click on the JNLP file downloaded by Chrome > Always open files of this type.

There is no simple way to enable autostart of Java applications in Safari. Also, Safari doesn't show immediately a link to the files dowloaded. Either click on the Download button (see image below) or open your Downloads folder before executing the JNLP file (JNLP files must be associated to Java Web Start via Right-click on the file > Get Info).

Internet Explorer and Firefox should no problem autostarting WingJ.


"Not Responding" on Windows

This issue is usually solved by increasing the maximum heap size that the JVM can use (see below).


Allowing WingJ to use more memory (Java Web Start)

Without specifying memory requirements, Java only allows applications to use up to 250-300 MB of memory. Memory requirements can be specified to the Java Virtual Machine (JVM) to allow the application to use more memory. However, this maximum amount of memory called max heap size must be defined before launching the application. Unfortunatelly, this parameter has not be thought to be adjusted dynamically. Note that if the requested max heap size is larger than the amount of free system memory available (also subject to additional conditions), the JVM will display the message "Could not create the Java virtual machine" before returning without even starting the application.

The max heap size can be defined in a startup file (JNLP file). If you have access to a 64-bit operating system, a 64-bit Java installation and enough physical memory, you can use the 1 GB, 2 GB or 4 GB version of WingJ. By default, clicking on "Launch WingJ" on the right side of this page launches WingJ with 1 GB of memory, which is usually enough for a normal use of WingJ (that also depends on the size of the image stacks that need to be loaded). If your system is still not able to allow 1 GB of memory, you can for sure launch WingJ without memory requirements (the amount of memory will be limited to 200-300 MB).

You can also specify custom memory requirements by downloading one of these JNLP files (Right-click on the link > Save as), opening the file with a text editor and changing the value after the element -Xmx (e.g. write -Xmx2000m for allowing WingJ to use up to 2 GB of memory).


Launching WingJ JNLP file from command (Java Web Start)

In a console, enter "javaws wingj_4G.jnlp" to launch WingJ (here with memory requirements set to 4 GB). Here the JNLP file "javaws wingj_4G.jnlp" is in the directory from where the command is run.


There are no line breaks in text files exported by WingJ (Windows)

The Notepad application on Windows doesn't recognized "\n" as line breaks. An excellent text editor for Windows is Notepad++.


Creating desktop shortcut fails (Java Web Start)

Once the application has been successfully downloaded, we setup Java Web Start so that it installs a shortcut on the desktop. However, the creation of this shortcut sometimes fails due to the implementation of Java Web Start. As this happens before our application starts, we unfortunately cannot do anything about it. To launch WingJ again, you can either:
  1. Click on "Launch WingJ" on the right side of this page
  2. Download one of the following JNLP file and place it on your desktop. Then, right-click on it and open it with Java Web Start. You can also simply double-click on it to start the application if Java Web Start has already been associated to the open files with the .jnlp extension.
  3. Open "Java Preferences" and locate the list of downloaded Java applications


TIFF image invisible

Any images created by WingJ can be saved with ImageJ > File > Save As. If the image is saved in TIFF format and the content of the produced image is invisible, first change the type of the image before saving it, for instance ImageJ > Image > Type > RGB Color.


WingJ doesn't function properly

Please submit an issue or contact .

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