Java for Google App Engine

When Google App Engine first came out I was really surprised it didn’t support Java, because Google was (and is) really pushing GWT, so to have them release a web deployment platform that did not support their own favorite framework was odd. However they have now released a preview version of Google App Engine running Java. It doesn’t do everything I might want, for instance Lift doesn’t run on it out of the box and it doesn’t allow you to spawn your own threads (these problems are directly related). There is some work going on to make Lift work on it though (see the email thread).

Overall though I’m really excited. I have been looking for a platform that will allow me to run Java based web apps for a reasonable price and I think this is the first one that provides something that I may actually use. For a low traffic site it is free and it looks to me that the prices are pretty good even as the traffic increases.

Posted in Java, Scala

Installing and upgrading plugins in Eclipse

I have had problems with “No repository found at” errors while trying to install or update eclipse plugins. Other people have had similar problems (on the andriod forums for instance).

I found that the solution was to open eclipse on a fresh workspace (just specify an empty directory for the workspace it will create the stuff it needs). Once the install/upgrade is done I can just switch back to my normal workspace and everything is as it should be. The upgrades and installs are installation-wide so the workspace change does not effect them. For some reason the stuff in my workspace was causing problems. It doesn’t make much sense really.

Posted in Tooling

Installing Subversive on Eclipse

I ran into a problem with installing Subversive (An eclipse plugin that interfaces to Subversion). The issue is that the plugin comes in 2 pieces that are both required: the Subversive plug-in and the Subversive SVN Connectors plug-in. This was not obvious to me and I ran into this problem not once but twice.

The solution is to add these 2 update sites (current as of Apr 2nd, 2009):

• http://www.polarion.org/projects/subversive/download/eclipse/2.0/update-site/
• http://download.eclipse.org/technology/subversive/0.7/update-site/

And install the following features from them:

• Subversive SVN Team Provider (from the http://download.eclipse.org/technology/subversive/0.7/update-site/ site)
• Subversive SVN Connectors (from the http://www.polarion.org/projects/subversive/download/eclipse/2.0/update-site/ site)
• SVNKit 1.2.2 Implementation (from the http://www.polarion.org/projects/subversive/download/eclipse/2.0/update-site/ site)

The error message in the eclipse logs was as follows when I failed to add the site for and install the “Subversive SVN Team Provider”. I hope this will help people find this and not have the same problems I did.

!ENTRY org.eclipse.equinox.p2.ui 4 10005 2009-04-06 15:30:28.470
!MESSAGE Cannot complete the request.  See the details.
!SUBENTRY 1 org.eclipse.equinox.p2.ui 4 10005 2009-04-06 15:30:28.470
!MESSAGE Cannot complete the request.  See the details.
!SUBENTRY 1 org.eclipse.equinox.p2.director 4 0 2009-04-06 15:30:28.470
!MESSAGE Unsatisfied dependency: [org.polarion.eclipse.team.svn.connector.feature.group 2.1.0.I20090213-1500] requiredCapability: org.eclipse.equinox.p2.iu/org.eclipse.team.svn.feature.group/[0.7.2.I20080801
-1500,1.0.0)
!SUBENTRY 1 org.eclipse.equinox.p2.director 4 0 2009-04-06 15:30:28.470
!MESSAGE Unsatisfied dependency: [org.polarion.eclipse.team.svn.connector.svnkit15.feature.group 2.1.0.I20090213-1500] requiredCapability: org.eclipse.equinox.p2.iu/org.eclipse.team.svn.feature.group/[0.7.2.I20080801-1500,1.0.0)
!SUBENTRY 1 org.eclipse.equinox.p2.director 4 0 2009-04-06 15:30:28.470
!MESSAGE Unsatisfied dependency: [org.polarion.eclipse.team.svn.connector.svnkit15 2.1.0.I20090213-1500] requiredCapability: osgi.bundle/org.eclipse.team.svn.core/0.0.0
!SUBENTRY 1 org.eclipse.equinox.p2.director 4 0 2009-04-06 15:30:28.470
!MESSAGE Unsatisfied dependency: [org.polarion.eclipse.team.svn.connector.svnkit15 2.1.0.I20090213-1500] requiredCapability: osgi.bundle/org.eclipse.team.svn.core/0.0.0
!SUBENTRY 1 org.eclipse.equinox.p2.director 4 0 2009-04-06 15:30:28.471
!MESSAGE Unsatisfied dependency: [org.polarion.eclipse.team.svn.connector.feature.group 2.1.0.I20090213-1500] requiredCapability: org.eclipse.equinox.p2.iu/org.eclipse.team.svn.feature.group/[0.7.2.I20080801-1500,1.0.0)
!SUBENTRY 1 org.eclipse.equinox.p2.director 4 0 2009-04-06 15:30:28.471
!MESSAGE Unsatisfied dependency: [org.polarion.eclipse.team.svn.connector.svnkit15.feature.group 2.1.0.I20090213-1500] requiredCapability: org.eclipse.equinox.p2.iu/org.eclipse.team.svn.feature.group/[0.7.2.I20080801-1500,1.0.0)
!SUBENTRY 1 org.eclipse.equinox.p2.director 4 0 2009-04-06 15:30:28.471
!MESSAGE Unsatisfied dependency: [org.polarion.eclipse.team.svn.connector.svnkit15.feature.group 2.1.0.I20090213-1500] requiredCapability: org.eclipse.equinox.p2.iu/org.polarion.eclipse.team.svn.connector.feature.group/0.0.0
!SUBENTRY 1 org.eclipse.equinox.p2.director 4 0 2009-04-06 15:30:28.471
!MESSAGE Unsatisfied dependency: [org.polarion.eclipse.team.svn.connector.svnkit15.feature.group 2.1.0.I20090213-1500] requiredCapability: org.eclipse.equinox.p2.iu/org.polarion.eclipse.team.svn.connector.svnkit15/[2.1.0.I20090213-1500,2.1.0.I20090213-1500]

Posted in Java, Tooling