Confluence going down frequently

Hi Team,

Confluence is going down frequently and in logs we could see the below error.

2015-10-27 16:51:05,239 http-bio-8443-exec-78 WARN Pu8u7b8 1011x45835x6 ztu3pe 10.101.1.124 /rest/analytics/1.0/publish/bulk [analytics.client.browser.PublisherResource] BrowserEvent property values should not be Collections or Maps. name=kickass.inlineEdit, properties=

{issueId=249026, savedFieldIds=[customfield_10010], duration=1069, context_pageSession=bp7fxxii7iwzmgboywv8v, context_pageTime=1982995}

Exception in thread "Thread-476" java.lang.NullPointerException
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.getCommentManager(DefaultConnectorJIRAUtil.java:1708)
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.mapCommentToRemoteBeanForSystem(DefaultConnectorJIRAUtil.java:1152)
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.pushComment(DefaultConnectorJIRAUtil.java:1044)
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.pushComments(DefaultConnectorJIRAUtil.java:1018)
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.pushComments(DefaultConnectorJIRAUtil.java:1034)
at net.customware.plugins.connector.jira.listener.ConnectorIssueEventListener$2.run(ConnectorIssueEventListener.java:216)
at java.lang.Thread.run(Thread.java:745)
Exception in thread "Thread-477" java.lang.NullPointerException
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.getCommentManager(DefaultConnectorJIRAUtil.java:1708)
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.mapCommentToRemoteBeanForSystem(DefaultConnectorJIRAUtil.java:1152)
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.pushComment(DefaultConnectorJIRAUtil.java:1044)
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.pushComments(DefaultConnectorJIRAUtil.java:1018)
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.pushComments(DefaultConnectorJIRAUtil.java:1034)
at net.customware.plugins.connector.jira.listener.ConnectorIssueEventListener$2.run(ConnectorIssueEventListener.java:216)
at java.lang.Thread.run(Thread.java:745)
2015-10-27 16:51:54,802 StreamsCompletionService::thread-272 WARN aagustin 1011x46761x6 13pgbdv 10.101.1.124 /plugins/servlet/streams [apache.commons.httpclient.SimpleHttpConnectionManager] SimpleHttpConnectionManager being used incorrectly. Be sure that HttpMethod.releaseConnection() is always called and that only one thread and/or method is using this connection manager at a time.
2015-10-27 16:52:15,830 http-bio-8443-exec-17 WARN aagustin 1012x47009x9 13pgbdv 10.101.1.124 /plugins/servlet/streams [atlassian.streams.internal.StreamsCompletionService] Registering failure for stream provider JIRA due to cancellation (timeout)
2015-10-27 16:52:15,830 http-bio-8443-exec-17 WARN aagustin 1012x47009x9 13pgbdv 10.101.1.124 /plugins/servlet/streams [atlassian.streams.internal.StreamsCompletionService] Registering failure for stream provider JIRA due to error timeout
2015-10-27 16:52:35,915 http-bio-8443-exec-44 WARN xMa1t7i8 1012x47448x6 kzlscm 10.101.1.124 /secure/AttachFile!default.jspa [webwork.view.taglib.IteratorTag] Value is null! Returning an empty set.
Exception in thread "Thread-491" java.lang.NullPointerException
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.getCommentManager(DefaultConnectorJIRAUtil.java:1708)
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.mapCommentToRemoteBeanForSystem(DefaultConnectorJIRAUtil.java:1152)
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.pushComment(DefaultConnectorJIRAUtil.java:1044)
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.pushComments(DefaultConnectorJIRAUtil.java:1018)
at net.customware.plugins.connector.jira.util.DefaultConnectorJIRAUtil.pushComments(DefaultConnectorJIRAUtil.java:1034)
at net.customware.plugins.connector.jira.listener.ConnectorIssueEventListener$2.run(ConnectorIssueEventListener.java:216)
at java.lang.Thread.run(Thread.java:745)
2015-10-27 16:53:04,164 http-bio-8443-exec-40 ERROR Kr0l6j1 1013x47643x5 gfujw7 10.101.1.124 /secure/QuickEditIssue.jspa [connector.jira.listener.ConnectorIssueEventListener] class net.customware.plugins.connector.jira.listener.ConnectorIssueEventListener
java.lang.NullPointerException