Make sure you have enough memory space to run the app. 5 GB RAM / 30 GB VM / 40 GB installation ,
The space allocated in server to run the demo application is not comfortable.
Some times restart the server will close this issue else for the permenant fix, increse the application execution memory space in the server.
Increase -XX:PermSize and -XX:MaxPermSize.
export JVM_ARGS="-Xmx1024m -XX:PermSize=256m -XX:MaxPermSize=512m"