Java web applications supervision and faulttolerance

Question

Note: The author of this question has some Java background, but is a complete newbie in Java EE.

I would like to know if there exists a mature tool to supervise Java web applications.

For example, if I have two Java servers (let us call them 1 and 2), running on different physical boxes, which write to a MySQL database on the other physical machine, and a main web application which frequently reads from this database:

How can I supervise servers 1 and 2? Is it possible to automatically restart the servers if they crash? Are there any ways to manage them the way Erlang/OTP does?

Answer 1

Service wrapper is good for restarting, and there are a lot of tool to monitor healths of java servers. Java provides JMX extenstion, which allows insights (and management) of almost everything in JVM and server environments. There is even generic monotoring console provided by JRE ( jConsole )

In case you need more services, you can grap hyperic - this is pretty nice dashboard which can provide you with lots of information and monitoring probes out of the box.

Answer 2

Although not equivalent to Erlang's supervisors, you can use the Java Service Wrapper ( http://wrapper.tanukisoftware.com/ ) to restart your JVM if the VM crashes or becomes unresponsive.