Terry,

Thanks for the tip on:

runtime.realTimeTimer.defaultTaskQueueSize

The setting was adjusted to a max of 2. The FATAL message still occurs. Periodicity is around a minute between occurrences. It seems better than it was but still nagging away.

If you're not seeing the same thing on your end there must be a configuration difference on my end. Dealing with configuration problems is tiresome for all involved. With that in mind, I highly recommend Docker. If Mango were available on the Docker hub I'd definitely use it.

On a new installation of Mango I'm having the same problem. The fix above regarding the adjustment of the JVM parameter was put in place. However, urgent messages were generated at approximately the same frequency as before the JVM adjustment.

The urgent event message is as follows:

High priority task: com.serotonin.m2m2.util.timeout.TimeoutTask@653124b was rejected because it is 
already running. 

I was able to strangle the urgent notices on the Mango dashboard by going to: System settings >> System event alarm levels >> Rejected work item >> None. However, this fix ignores that there's a and persistent problem as reported by the system.

Why does Mango keep tapping on a task that is already running and is there a way to prevent it? Is there a way to find out what the task does?

Configuration
OS: Ubuntu server 16.04
Java version: 1.8.0_101
Mango: 2.7.12

Regards,
Jake

I'm not having luck installing Mango on a Mac OSX 10.5.8 with Java 1.6.0. File name was changed from "ma-start.sh" to "ma-start.command". Line 15 was changed from "ma-start.sh" to "ma-start.command". "chmod +x ma-start.command" was executed via terminal to gain access to the file. The following was returned in the terminal window upon execution of "ma-start.command":

Applications/Mango/ma-start.command ; exit;
Exception in thread "main" java.lang.UnsupportedClassVersionError: Bad version number in .class file
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:676)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:317)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:280)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:375)
logout

[Process completed]

Jake