Troubleshooting

catkin_make stuck on downloading gradle, or resolving dependencies

The rosjava build system tries to satisfy dependencies by connecting to a remote repository. Internet access is required for this. Further, if you are behind a proxy server then you may have trouble connecting from java as it has its own proxy settings (at least on my system). To set the Java proxy settings, edit the file /etc/java-6-openjdk/net.properties file.

java nodes timing out on subscribing, giving strange IP

If your node fails to subscribe to another nodes publications, then it may be that Java can't resolve your hostname and is not using the standard resolve library. To solve this, in every terminal you should set your IP address:

export ROS_IP=my.ip.addd.ress