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XMM-Newton Science Archive Interface FAQ



This page is a compilation of questions and answers to the most common problems that users have experienced when using the interface for the XSA.
Clicking on a question will take you down the page to the answer.

Q1. How can I open the xsa.jnlp file extension for launching the Java Web Start?
Q2. Applets vs. Web Start applications
Q3. Sometimes the XSA gets frozen and is not possible to press any button or fill any text field in the Archive.
Q4. I can not type in my password when login in
Q5. How can I check the version of the Java Virtual Machine that I am currently using?
Q6. How can I enable Java in my web browser?
Q7. Where can I find help on how to use the XSA browser?

If you require further information, please contact the XMM-Newton Helpdesk who will be happy to deal with your enquiry.




Q1. How can I open the xsa.jnlp file extension for launching the Java Web Start?
A1.
If you have Java already installed, for opening xsa.jnlp in your system you have to define which application will open it, depending on your operating system (for instance for Linux you can use javaws and for Mac you can use OpenJNLP). (see also: Launching an Application Using Java Web Start Software at http://www.java.com/en/download/faq/java_webstart.xml)


Q2. Applets vs. Web Start applications
A2.
For most XSA users the Web Start application has an advantage over applets in that it overcomes many compatibility problems with browsers' Java plugins, different JVM versions, memory restrictions, etc., because these are configured by the Archive itself according to its needs.
Unlike Java applets, Web Start applications do not run inside the browser but in a separate "sandbox". Applets, instead, are executed in a sandbox restricted by the browser where they run.
Only for old version browsers Java Web Start may not work and therefore the Applet interface should be used.


Q3. Sometimes the XSA gets frozen and is not possible to press any button or fill any text field in the Archive.
A3.
This is a problem of the Java Virtual Machine, follow these instructions:
  • Close all open sessions (File menu, option 'Quit') in your browser.
  • Check if a process called 'java_vm' exists executing in a terminal: [ ps -auxww|grep java_vm ]
  • If this is the case, then kill it executing in a terminal: [ kill -9 process_id ]
  • Re-start your browser.


Q4. I can not type my password when login in
A4.
This is a known Java problem that SUN shall fix soon. The workaround is to click on one of the help items (blue components) and close it again. This will, in principle, make the cursor alive and the input from keyboard allowed again. In the case the symptom persists it is also advisable to clean the Java cache and restart the archive.


Q5. How can I check the version of the Java Virtual Machine that I am currently using?
A5.
Sun provides useful tools to check the version of the Java Virtual Machine you are currently using
and the details of the operating system in which you are running the XSA Archive.
If Java is not installed in your machine follow these instructions to get the latest stable version.
More detailed information and tools about Java versions/plug-ins can be found here.


Q6. How can I enable Java in my web browser?
A4.
If Java applications are disabled in your web browser you will not be able tu use the XSA Archive.
To enable Java in your web browser follow these instructions.
Beware that the Java plugin on Unix/Linux platforms has to be linked to your web browser.
The Java library has to be placed or linked from the plugins folder under your browser folder
(see examples here).
More detailed information and tools about Java versions/plug-ins can be found here.


Q7. Where can I find help on how to use the XSA browser.
A7.
Have a look at the Guided tour of the XSA. Once you are running the XSA browser click on the labels (like Query Specification), and you will get specific help.

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This page was last updated on 1 January, 1970.