This morning I ran into a problem with MyEclipse which cost me a couple of hours, so I’m putting it here, in case this happens to me again.
I had broken a build/deployment, and in the process of fixing it, I removed my application deployment from within Eclipse, and then used a build script (outside of Eclipse) to generate and deploy a new version directly to tomcat. After I figured out what the problem was to fix that deployment, it was time to get back to autodeploy, so I could keep working. The problem was, the next time I tried to deploy from within Eclipse I just couldn’t.
The symptoms were: I would go into the Manage Deployments dialog box, choose my project, choose Add to pick a server (tomcat), and the “Exploded Archive (development mode)” setting would be set, but the Deploy Location textbox was empty and grayed out, and the Finish button was also grayed out.
Digging through the Eclipse error log, I found a NullPointerException on com.genuitec.eclipse.ast.deploy.core.DeploymentManager.computeDeploymentLocation.
After some searching of the MyEclipse forums, I saw that this was a problem with the .mymetadata file in the project. Somehow (?) this file had gotten deleted. Luckily, I had another, older version of this file in another branch of my project that I was able to copy into my project to fix things.