How to resolve the issue of "/messages_gui.log (Permission denied)"

Summary

In the message_gui_server.log, you can find the below error many times:

[9/12/18 20:52:10:264 GMT] 000000a1 SystemError log4j:ERROR setFile(null,true) call failed.
[9/12/18 20:52:10:266 GMT] 000000a1 SystemError java.io.FileNotFoundException: /messages_gui.log (Permission denied)
...
[9/12/18 20:52:10:453 GMT] 000000a1 SystemError log4j:ERROR setFile(null,true) call failed.

[9/12/18 20:52:10:454 GMT] 000000a1 SystemError java.io.FileNotFoundException: /generaltable.log (Permission denied)

....

[9/12/18 20:52:10:485 GMT] 000000a1 SystemError log4j:ERROR setFile(null,true) call failed.
[9/12/18 20:52:10:485 GMT] 000000a1 SystemError java.io.FileNotFoundException: /performance.log (Permission denied)


As you know, these log file names (messages_gui.log, generaltable.log,performance.log) were recorded in the file log4j.properties. So you know that CwS defining log4j.properties file can be gotten by was jvm in your environment. The log error should have relation that jvm can't file the environment variable. For example, for the setting "log4j.appender.R.File=$EGO_TOP/messages_gui.log", it doesn't know the value of $EGO_TOP in log4j.properties. So it tries to output to /message_gui.log

The solution is to change "$EGO_TOP/messages_gui.log" to an absolute path. Make sure that directory's access authority is enough.
After changing the file path to absolute path, the issue is resolved and the message_gui.log can be seen.