在Tomcat 7中获取Java堆空间问题

Question

我正在开发一个Java EE Web应用程序,它由Struts,Spring和Hibernate组成.在那,我反复得到以下例外(至少每天一次).

例外1:

Exception in thread "Timer-0" java.lang.OutOfMemoryError: Java heap space
    at java.util.LinkedHashMap.createEntry(LinkedHashMap.java:424)
    at java.util.LinkedHashMap.addEntry(LinkedHashMap.java:406)
    at java.util.HashMap.put(HashMap.java:385)
    at sun.util.resources.OpenListResourceBundle.loadLookup(OpenListResourceBundle.java:118)
    at sun.util.resources.OpenListResourceBundle.loadLookupTablesIfNecessary(OpenListResourceBundle.java:97)
    at sun.util.resources.OpenListResourceBundle.handleGetObject(OpenListResourceBundle.java:58)
    at sun.util.resources.TimeZoneNamesBundle.handleGetObject(TimeZoneNamesBundle.java:59)
    at java.util.ResourceBundle.getObject(ResourceBundle.java:368)
    at java.util.ResourceBundle.getObject(ResourceBundle.java:371)
    at java.util.ResourceBundle.getStringArray(ResourceBundle.java:351)
    at sun.util.TimeZoneNameUtility.retrieveDisplayNames(TimeZoneNameUtility.java:100)
    at sun.util.TimeZoneNameUtility.retrieveDisplayNames(TimeZoneNameUtility.java:81)
    at java.util.TimeZone.getDisplayNames(TimeZone.java:399)
    at java.util.TimeZone.getDisplayName(TimeZone.java:350)
    at java.text.SimpleDateFormat.subFormat(SimpleDateFormat.java:1110)
    at java.text.SimpleDateFormat.format(SimpleDateFormat.java:899)
    at java.text.SimpleDateFormat.format(SimpleDateFormat.java:869)
    at java.text.DateFormat.format(DateFormat.java:316)
    at org.apache.log4j.helpers.PatternParser$DatePatternConverter.convert(PatternParser.java:443)
    at org.apache.log4j.helpers.PatternConverter.format(PatternConverter.java:65)
    at org.apache.log4j.PatternLayout.format(PatternLayout.java:506)
    at org.apache.log4j.WriterAppender.subAppend(WriterAppender.java:310)
    at org.apache.log4j.DailyRollingFileAppender.subAppend(DailyRollingFileAppender.java:369)
    at org.apache.log4j.WriterAppender.append(WriterAppender.java:162)
    at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:251)
    at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:66)
    at org.apache.log4j.Category.callAppenders(Category.java:206)
    at org.apache.log4j.Category.forcedLog(Category.java:391)
    at org.apache.log4j.Category.log(Category.java:856)
    at com.mchange.v2.log.log4j.Log4jMLog$Log4jMLogger.log(Log4jMLog.java:161)
    at com.mchange.v2.log.log4j.Log4jMLog$Log4jMLogger.warning(Log4jMLog.java:221)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector.run(ThreadPoolAsynchronousRunner.java:624)

例外2:

Exception in thread "com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1" java.lang.OutOfMemoryError: GC overhead limit exceeded
    at java.util.HashMap.addEntry(HashMap.java:753)
    at java.util.HashMap.put(HashMap.java:385)
    at java.util.HashSet.add(HashSet.java:200)
    at com.mchange.v2.c3p0.util.ConnectionEventSupport.addConnectionEventListener(ConnectionEventSupport.java:39)
    at com.mchange.v2.c3p0.impl.NewPooledConnection.addConnectionEventListener(NewPooledConnection.java:237)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.refurbishResourceOnCheckin(C3P0PooledConnectionPool.java:292)
    at com.mchange.v2.resourcepool.BasicResourcePool.attemptRefurbishResourceOnCheckin(BasicResourcePool.java:1606)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$200(BasicResourcePool.java:32)
    at com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask.run(BasicResourcePool.java:1228)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
Exception in thread "com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#4" java.lang.OutOfMemoryError: GC overhead limit exceeded
Exception in thread "Task-Thread-for-com.mchange.v2.async.ThreadPerTaskAsynchronousRunner@6c8bb765" java.lang.OutOfMemoryError: GC overhead limit exceeded
Exception in thread "com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#3" java.lang.OutOfMemoryError: GC overhead limit exceeded
Exception in thread "com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2" java.lang.OutOfMemoryError: GC overhead limit exceeded
Exception in thread "Task-Thread-for-com.mchange.v2.async.ThreadPerTaskAsynchronousRunner@6c8bb765" java.lang.OutOfMemoryError: GC overhead limit exceeded
Exception in thread "Task-Thread-for-com.mchange.v2.async.ThreadPerTaskAsynchronousRunner@6c8bb765" java.lang.OutOfMemoryError: GC overhead limit exceeded
Exception in thread "Timer-0" java.lang.OutOfMemoryError: Java heap space
Exception in thread ""http-bio-8080"-exec-2" java.lang.OutOfMemoryError: Java heap space
Exception in thread ""http-bio-8443"-Acceptor-0" java.lang.OutOfMemoryError: Java heap space
Exception in thread ""http-bio-8080"-exec-3" java.lang.OutOfMemoryError: Java heap space
Exception in thread "com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#4" java.lang.OutOfMemoryError: GC overhead limit exceeded

这是我的配置:

-server -Xms2048m -Xmx2048m
-XX:NewSize=1024m -XX:MaxNewSize=1024m -XX:PermSize=512m
-XX:MaxPermSize=1024m -XX:+DisableExplicitGC"

任何人都可以指出,由于这种配置或其他任何原因我得到这个例外吗？

我知道我的代码中存在一些问题,但我如何预测会发现这些问题？我已经尝试过Eclipse MAT来分析内存转储但是没有任何想法.

我已经尝试过为此增加内存但除了减少这种异常的频率之外没有多大帮助.

请帮忙.提前致谢.

Answer 1

关于为什么会出现这些异常，有两种选择。首先，您的应用程序可能只需要这么多内存。其次，您的应用程序泄漏内存。无论哪种情况，MAT 都是诊断问题的好工具。支配树和泄漏嫌疑人报告是一个很好的起点。