JGridstart/Java Web Start Deployment

The introduction of Java Web Start has made deployment of Java applications a lot better. Now that a user can run a full application relatively easily from the web, there remains the issue of making sure that the user has installed a Java runtime environment. White this is covered by Sun, it is not yet a fully integrated smooth procedure for the end-user. Differences in browsers complicate the issue.

This page is an attempt to describe the behaviour of various major web browsers, so that a Java Web Start launcher infrastructure consisting of HTML and Javascript can be written that makes the user experience as smooth as possible.

Web Browsers

Windows / Internet Explorer

Described in the Java developers guide. Uses an object tag that optionally compares the currently installed Java version to a supplied value, and runs an installer when needed. When the right Java version is installed, the object runs the JNLP file.

Windows / Mozilla

Mozilla and derivatives (most notably Firefox) has an auto-install method. Sun provides an xpinstall package for Windows on its autodl page. Its use may be derived from Mozilla's XPInstall plugin page for plugin developers: one needs to specify a type and codebase on an object tag. Details can best be learned from existing pages, like

Opera

Opera doesn't use the standard Java plugin but directly access the java library itself. This results in the issue that Java's mimetypes are not registered. Also Opera doesn't know about JNLP files by default and tries to open them as ordinary XML files, which may or may not work for users. Opera mentions in their knowledgebase that users should manually create a mimetype entry in Opera's preferences.