GlassFish 4 server stops automatically
I'm new to GlassFish, and to application servers in general. I have an Amazon EC2 instance running Ubuntu and have installed GlassFish 4. It starts up without problems, but after a while the GlassFish server just shuts down all by itself. I have looked through server.log, but everything seems normal, and there are no entries describing any failures or shut down. Any input on what can be the cause, or where I should look to find any clues would be appreciated.