Exceptions when stopping Tomcat

[Nicklas Nordborg]

This has been around for a long time... When stopping Tomcat using the script provided by Tomcat () there are several errors logged in catalina.out. Here is a few examples:

log4j:ERROR Error occured while converting date.
java.lang.NullPointerException
	at java.lang.System.arraycopy(Native Method)
	at java.lang.AbstractStringBuilder.getChars(AbstractStringBuilder.java:328)
	at java.lang.StringBuffer.getChars(StringBuffer.java:201)
	at org.apache.log4j.helpers.AbsoluteTimeDateFormat.format(AbsoluteTimeDateFormat.java:117)
	at java.text.DateFormat.format(DateFormat.java:316)
	at org.apache.log4j.helpers.PatternParser$DatePatternConverter.convert(PatternParser.java:444)
	at org.apache.log4j.helpers.PatternConverter.format(PatternConverter.java:64)
	at org.apache.log4j.PatternLayout.format(PatternLayout.java:503)
	at org.apache.log4j.WriterAppender.subAppend(WriterAppender.java:301)
	at org.apache.log4j.WriterAppender.append(WriterAppender.java:159)
	at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:230)
	at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:65)
	at org.apache.log4j.Category.callAppenders(Category.java:203)
	at org.apache.log4j.Category.forcedLog(Category.java:388)
	at org.apache.log4j.Category.info(Category.java:663)
	at net.sf.basedb.core.Application.stop(Application.java:573)
	at net.sf.basedb.core.Application$1.run(Application.java:543)
	at java.lang.Thread.run(Thread.java:619)
Exception in thread "Thread-18" java.lang.NullPointerException
	at org.apache.log4j.helpers.PatternConverter.spacePad(PatternConverter.java:106)
	at org.apache.log4j.helpers.PatternConverter.format(PatternConverter.java:82)
	at org.apache.log4j.PatternLayout.format(PatternLayout.java:503)
	at org.apache.log4j.WriterAppender.subAppend(WriterAppender.java:301)
	at org.apache.log4j.WriterAppender.append(WriterAppender.java:159)
	at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:230)
	at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:65)
	at org.apache.log4j.Category.callAppenders(Category.java:203)
	at org.apache.log4j.Category.forcedLog(Category.java:388)
	at org.apache.log4j.Category.info(Category.java:663)
	at net.sf.basedb.core.Application.stop(Application.java:573)
	at net.sf.basedb.core.Application$1.run(Application.java:543)
	at java.lang.Thread.run(Thread.java:619)

The problem seems to be that as the Java virtual machine is shutting down things the logging system is one of the first things to go. Later on, when Application.stop() is called, it will try to use a non-working logging system, which results in the exceptions.

This problem could be solved by a servlet that is configured to load on startup, and calls Application.start() in it's init() method and Application.stop() in it's destroy() method.

This was not really a big issue before, since everything was going down anyway. The only side effect was leaving a few session in the logged-in state instead of properly logging out all users.

When the 'services' extension point is in place (see #1036), it becomes more important that everything is actually stopped properly. For example, the upcoming FTP server () must be able to close existing connections properly.

[Nicklas Nordborg]

(In [4319]) Fixes #1040: Exceptions when stopping Tomcat