Run Java program from Eclipse Builders

Question

I want to run a Java program as a builder before the Java Builder kicks in. The Java class to be run is part of another project within the workspace.

I can add Program builder but I don't want to point explicitly to a Java VM as my teammates may have their Java installed in different location. Is there a way to achieve this without referring to a particular JVM executable?

EDIT: Added screenshot of Eclipse Builders to show which config I'm talking about. Screenshot of Eclipse Builders configuration

• greg-449: How are you specifying this builder?
• hawk: @greg-449 Check out the screenshot I added.

Answer 1

I can run the java program using a normal launcher (.launch file created using Run/Debug Configuration). I figured out a way to make that work as a Builder step.

Simply move the .launch to .externalToolBuilders and modify the .project file in a text editor to pick up that .launch file.

<buildCommand>
 <name>org.eclipse.ui.externaltools.ExternalToolBuilder</name>
 <triggers>full,incremental,</triggers>
 <arguments>
 <dictionary>
 <key>LaunchConfigHandle</key>
 <value>&lt;project&gt;/.externalToolBuilders/MyCustomJavaProgram.launch</value>
 </dictionary>
 </arguments>
</buildCommand>

Eclipse being the good boy it is, doesn't complain about the presence of a org.eclipse.jdt.launching.localJavaApplication as a Builder step and everything works smoothly. In fact if you edit this newly added Builder step it even shows the correct Edit launch configuration dialog.

• Lii: But manually adding a launch configuration file (.launch) to .externalToolBuilders is exactly the same as creating a Program Builder with the Builders dialog, isn't it? Why do it this way?

Answer 2

The best way to create a builder in Java is to create a plugin and use the org.eclipse.core.resources.builders extension point. Your builder class then extends the org.eclipse.core.resources.IncrementalProjectBuilder class and has access to lots of detail about what is being built.

This method does not require a JVM to be specified anywhere as your plugin runs as part of Eclipse.

• hawk: while that may be useful in general, in my case it's a bit of an overkill. i don't want to force a plugin installation on part of other team members either.