Installing and Using JavaTM Web Start

The newest examples in the Tutorial can be run using JavaTM Web Start software. This page answers some of the most common questions about Java Web Start and gives some troubleshooting tips. If you don't find the answer to your question or problem here, you might find it in the Java Web Start documentation (outside of the tutorial).

Note:  This is an early, incomplete draft. If you have specific suggestions for this page, please tell us. Thanks!
Common questions: Problems you might encounter:

Common Questions

Where do I get Java Web Start?
First off, you might not need to. If you've downloaded and installed J2SE v 1.4.1, then Java Web Start was automatically downloaded and, for many common browser and platform configurations, installed.

If you don't yet have Java Web Start, we recommend that you download and install the latest version of J2SE, in either JRE (runtime) or SDK (development) form. For more information, see the Java Web Start download instructions (outside of the tutorial).

How do I install it?
First, make sure you don't already have Java Web Start installed. You can do so by clicking on a JNLP link, such as this one: FormattedTextFieldDemo. If clicking that link doesn't cause Java Web Start to launch, follow the instructions in the Java Web Start installation guide (outside of the tutorial). If Java Web Start launches but the application doesn't run, see Problems You Might Encounter.
How do I customize it?
Use the Java Web Start Application Manager. For example, if you want to add a particular version of the Java runtime environment (JRE) or prevent an existing JRE version from being used by Java Web Start, choose the File > Preferences menu item and then, from the dialog that appears, the Java tab. The controls that you then see allow you to find, add, remove, enable, and disable each release of the JRE.

Problems You Might Encounter

My browser seems to find the JNLP file, but Java Web Start says it can't find it.
This situation usually happens when your browser and your copy of Java Web Start have different proxy settings. To fix this problem:
  1. Launch the Java Web Start Application Manager.
  2. Choose the File > Preferences menu item.
  3. Choose the General tab from the window that appears.
  4. Set the proxy to a better value. For example, if you're behind a firewall and Use Browser is selected, try selecting Manual and entering an HTTP proxy server and port (often 8080). If you aren't behind a firewall, try selecting None. Or, if Use Browser is initially unselected, try selecting it.
These instructions were tested with Java Web Start version 1.2.