Jira Service Desk became unavailable

[Nickolai Korzan]

Hello.

Yesterday we encountered the following problem:
Jira Service Desk became unavailable by URL. The problem was solved by restarting the jira service.

We analyzed the logs and found the following errors:

1. Catalina.log file

19-Feb-2020 00: 27: 02.172 SEVERE [ContainerBackgroundProcessor [StandardEngine [Catalina]]] org.apache.catalina.core.ContainerBase $ ContainerBackgroundProcessor.run Unexpected death of background thread [ContainerBackgroundProcessor [StandardEngine [Catalina]]]
java.lang.OutOfMemoryError: Java heap space

2. File localhost.log

19-Feb-2020 01: 38: 58.081 SEVERE [http-nio-8080-exec-12] org.apache.catalina.core.StandardHostValve.custom Exception Processing ErrorPage [errorCode = 500, location = / internal-error]
java.lang.IllegalStateException: getOutputStream () has already been called for this response

Also, the catalina.out file has a size of 773mb. Is this a normal size?
Could you tell me what these errors are connected with and how to avoid their repeated occurrence?