How to run plugin code in Eclipse automatically on startup?

Question

I want to create an Eclipse plugin that automatically runs in the background, as soon as the user opens the Eclipse IDE.

For example, I am building a Java Eclipse plugin that gets the current active file address, but I would like this plugin to always run in the background without user having to run it manually.

How to achieve this?

• greg-449: Look at the org.eclipse.ui.startup extension point
• Karthik Rocky: Simply Adding your piece of code in activator .start method Would also achieve that.
• Stephan Herrmann: @KarthikRocky: no, code in Activator.start() is only invoked when the containing plugin is activated. Due to lazy loading you normally have no control over this. The extension point mentioned by greg-449 serves this purpose. Alternatively, setting the startlevel of a plug-in can be used to force eager activation, but to configure the startlevel is more challenging than providing the said extension.
• Karthik Rocky: Stephan Herrmann- Hmmm okie. I understand completely now.. upvoted Greg answer too:-)

Answer 1

The org.eclipse.ui.startup extension point lets you define a class that is run early during workbench initialization.

The extension point looks something like:

<extension point="org.eclipse.ui.startup">
 <startup class="package.StartupClass"/>
</extension>

the class specified must implement the org.eclipse.ui.IStartup interface.

More details here

• LppEdd: What if I'm on a pure E4 plugin (not application) which has no access to IStartup?
• LppEdd: Ok. Debugging the platform (with compatibility layer) I've found that APP_STARTUP_COMPLETE is called just before IStartup implementations. Would be a good addition to the answer! Thanks Greg as always. The only difference is that IStartup is called through a Job, which tracks progress.