After I added more RAM to my machine, I restarted it. I discovered that Sesame is not working anymore and I keep getting the Change Server message.
I use Sesame 2.7.11, with Apache Tomcat 7-0.53 and Java 1.7.0_51_b13 on Ubuntu 13.10.
Here is the Tomcat error log:
May 20, 2014 6:29:55 PM org.openrdf.workbench.proxy.ServerValidator checkServerPrefixes
WARNING: server URL null does not have a prefix file: http: https:
May 20, 2014 6:29:55 PM org.openrdf.workbench.proxy.ServerValidator canConnect
WARNING: java.net.UnknownHostException: localhost
java.net.UnknownHostException: localhost
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:178)
...
at org.openrdf.workbench.proxy.ServerValidator.canConnect(ServerValidator.java:121)
at org.openrdf.workbench.proxy.ServerValidator.isValidServer(ServerValidator.java:76)
at org.openrdf.workbench.proxy.WorkbenchGateway.findWorkbenchServlet(WorkbenchGateway.java:251)
at org.openrdf.workbench.proxy.WorkbenchGateway.service(WorkbenchGateway.java:121)
at org.openrdf.workbench.base.BaseServlet.service(BaseServlet.java:136)
...
I am aware that there is a similar question (sesame 2.6.9 with tomcat 7 set up won't work), but the Tomcat error in my case seems to be different. Instead of localhost in my actual log you can find the address of my web server (so let's say data.something.com).