Tips for using JWS on Windows PCs

28-Mar-2007, Kurt Biery

I believe that most of the problems that users have encountered when trying to run the snapshot producer on a Windows PC have been related to installing Java and/or enabling Java Web Start. With this in mind, I have put together the following notes on JWS and Windows.

Background

At this time, the preferred version of Java for use with S³ is 1.5.0_11. So, my goal whenever I set up a new workstation for producing snapshots is so associate the "jnlp" file extension with a copy of the 1.5.0_11 javaws executable on the machine and ensure that this version of Java will be used when the producer runs. On some Windows PCs that I have tested, this is already installed and configured. On others, I need to install the correct version of Java and set up the associations by hand.

Before listing any tips, I should say that you can check whether a particular workstation (Windows or Linux) is enabled for Java Web Start using the following link: http://lhcsrv1.fnal.gov:8082/demo/timevers.jnlp. If JWS is working, you may need to click through some "are you willing to allow this application to start" dialog boxes, but then you should see a small window open with a current timestamp from the local workstation and the version of the Java runtime that is being used locally for JWS applications.

Tips

To check for existing versions of the Java Web Start executable:

Open Windows Explorer and select the Search view. Specify that you want to search for "All files and folders", enter a filename of "javaws.exe" (without the quotes), specify a search location of "Local Hard Drives", and click on the Search button.

To associate a particular version of the javaws executable with the jnlp file extension, you can use the following steps:

Open an instance of Windows Explorer
Select Tools->Folder Options
Select the "File Types" tab
Look for JNLP in the list of extensions
If you find JNLP in the list,
- Select it and click on the Advanced button
- In the "Edit File Type" popup, click on Edit
- In the "Editing action for type: JNLP File" popop, type in a new path to javaws.exe or use the Browse button to find a new one
- Click OK in each of the popup windows to save your change
If you don't find JNLP in the list,
- Click on the New button
- Type in JNLP in the extension text box and click on the OK button - this will add it to the list
- Use the steps above to associate the extension with a particular version of javaws.exe

To install a new version of Java, I use the following steps:

Download version 1.5.0_11 of the JRE from Sun:
- Open a browser window and navigate to http://java.sun.com
- Click on "Java SE" in the Popular Downloads section
- Select the Previous Releases sub-tab
- Select J2SE 5.0 Downloads
- Click on the Download button for Java Runtime Environment (JRE) 5.0 Update 11
- Accept the license agreement
- Click on the link for Windows Offline Installation
- Save the file to disk
Run the downloaded executable
- Choose the Custom Setup and Accept the license agreement
- Modify the Install directory if needed, and click on Next
- Deselect the browser plugin registration checkboxes if you want, and click Next
- wait while it installs

The configuration of the Java runtime on a Windows machine can be accessed choosing Start-->Control Panel, and then double-clicking on the Java icon. From the Java Control Panel, you can select which versions are available for JWS applications by choosing the "Java" tab and then clicking on the View button in the Java Application Runtime Settings section. In addition, you can remove or execute cached versions of JWS applications with the following steps:

Start->Control Panel
Double-click the Java icon
In the Java Control Panel, select the General tab
Select the Settings button in the Temporary Internet Files subsection
In the Temporary Files Settings dialog, click on the View Applications button
Select and run or remove various cached copies of applications
Close the dialog boxes, when done, using File->Exit or the OK button