查找java.lang.OutOfMemoryError的根本原因：使用Eclipse MAT查找java堆空间

Question

我试图找出哪个方法/循环在我的应用程序中给了Java . lang . out of memory error:Java堆空间。我对使用Eclipse Memory Analyzer分析java应用程序还很陌生。

在图像中，很明显调用JNI本地具有最大保留堆，但我们的应用程序中没有任何JNI调用。

请检查并确认内存泄漏是由调用任何本机代码（JNI Local）还是使用任何字符串迭代或其他原因引起的？

作为参考，我在这里附上总的概述和堆栈跟踪。hprof文件:

Accumulated Objects by Class
Label   Number of Objects   Used Heap Size  Retained Heap Size
java.lang.String
First 10 of 15,252,128 objects  15,252,128  488,068,096     2,317,743,632
Thread Details

Thread WorkManager(2)-8

Thread Properties
Object / Stack Frame    java.lang.Thread @ 0x69af09608
Name    WorkManager(2)-8
Shallow Heap    112
Retained Heap   2,384,942,672
Context Class Loader    org.jboss.util.loading.DelegatingClassLoader @ 0x6912bf868
Is Daemon   true

    Total: 6 entries


Thread Stack

WorkManager(2)-8
  at java.lang.StringCoding.decode(Ljava/lang/String;[BII)[C (StringCoding.java:185)
  at java.lang.String.<init>([BIILjava/lang/String;)V (String.java:451)
  at java.lang.String.<init>([BLjava/lang/String;)V (String.java:523)
  at java.io.UnixFileSystem.list(Ljava/io/File;)[Ljava/lang/String; (Native Method)
  at java.io.File.list()[Ljava/lang/String; (File.java:990)
  at java.io.File.listFiles(Ljava/io/FilenameFilter;)[Ljava/io/File; (File.java:1107)
  at com.adobe.idp.dsc.service.file.impl.WatchedFolderUtils.resolveDuplicateFile(Ljava/lang/String;Z)Ljava/io/File; (WatchedFolderUtils.java:515)
  at com.adobe.idp.dsc.provider.service.file.write.impl.FileResultHandlerImpl.resolveDestination(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Z)Ljava/io/File; (FileResultHandlerImpl.java:308)
  at com.adobe.idp.dsc.provider.service.file.write.impl.FileResultHandlerImpl.preserveFiles(Lcom/adobe/idp/dsc/registry/infomodel/Endpoint;Ljava/lang/String;Ljava/lang/String;)V (FileResultHandlerImpl.java:817)
  at com.adobe.idp.dsc.provider.service.file.write.impl.FileResultHandlerImpl.saveResults(Lcom/adobe/idp/dsc/InvocationResponse;Lcom/adobe/idp/dsc/registry/infomodel/Endpoint;Ljava/lang/String;Ljava/lang/String;)V (FileResultHandlerImpl.java:493)
  at com.adobe.idp.dsc.provider.service.file.write.impl.FileResultHandlerImpl.handleSuccess(Ljava/lang/Object;Ljava/util/Map;)V (FileResultHandlerImpl.java:104)
  at com.adobe.idp.dsc.provider.service.file.write.impl.FileResultHandlerImpl.handleSuccess(Lcom/adobe/idp/dsc/InvocationResponse;)V (FileResultHandlerImpl.java:73)
  at sun.reflect.GeneratedMethodAccessor2229.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (Unknown Source)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (Method.java:616)
  at com.adobe.idp.dsc.component.impl.DefaultPOJOInvokerImpl.invoke(Lcom/adobe/idp/dsc/InvocationRequest;)Lcom/adobe/idp/dsc/InvocationResponse; (DefaultPOJOInvokerImpl.java:118)
  at com.adobe.idp.dsc.interceptor.impl.InvocationInterceptor.intercept(Lcom/adobe/idp/dsc/component/ComponentContext;Lcom/adobe/idp/dsc/InvocationRequest;Lcom/adobe/idp/dsc/interceptor/RequestInterceptorChain;)Lcom/adobe/idp/dsc/InvocationResponse; (InvocationInterceptor.java:140)
  at com.adobe.idp.dsc.interceptor.impl.RequestInterceptorChainImpl.proceed(Lcom/adobe/idp/dsc/component/ComponentContext;Lcom/adobe/idp/dsc/InvocationRequest;)Lcom/adobe/idp/dsc/InvocationResponse; (RequestInterceptorChainImpl.java:60)
  at com.adobe.idp.dsc.interceptor.impl.DocumentPassivationInterceptor.intercept(Lcom/adobe/idp/dsc/component/ComponentContext;Lcom/adobe/idp/dsc/InvocationRequest;Lcom/adobe/idp/dsc/interceptor/RequestInterceptorChain;)Lcom/adobe/idp/dsc/InvocationResponse; (DocumentPassivationInterceptor.java:53)
  at com.adobe.idp.dsc.interceptor.impl.RequestInterceptorChainImpl.proceed(Lcom/adobe/idp/dsc/component/ComponentContext;Lcom/adobe/idp/dsc/InvocationRequest;)Lcom/adobe/idp/dsc/InvocationResponse; (RequestInterceptorChainImpl.java:60)
  at com.adobe.idp.dsc.transaction.interceptor.TransactionInterceptor$1.doInTransaction(Lcom/adobe/idp/dsc/transaction/TransactionContext;)Ljava/lang/Object; (TransactionInterceptor.java:74)
  at com.adobe.idp.dsc.transaction.impl.ejb.adapter.EjbTransactionCMTAdapterBean.execute(Lcom/adobe/idp/dsc/transaction/TransactionContext;Lcom/adobe/idp/dsc/transaction/TransactionCallback;)Ljava/lang/Object; (EjbTransactionCMTAdapterBean.java:357)
  at com.adobe.idp.dsc.transaction.impl.ejb.adapter.EjbTransactionCMTAdapterBean.doSupports(Lcom/adobe/idp/dsc/transaction/TransactionDefinition;Lcom/adobe/idp/dsc/transaction/TransactionCallback;)Ljava/lang/Object; (EjbTransactionCMTAdapterBean.java:227)
  at sun.reflect.GeneratedMethodAccessor698.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (Unknown Source)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (Method.java:616)
  at org.jboss.invocation.Invocation.performCall(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object; (Invocation.java:386)
  at org.jboss.ejb.StatelessSessionContainer$ContainerInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (StatelessSessionContainer.java:233)
  at org.jboss.resource.connectionmanager.CachedConnectionInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (CachedConnectionInterceptor.java:156)
  at org.jboss.ejb.plugins.StatelessSessionInstanceInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (StatelessSessionInstanceInterceptor.java:173)
  at org.jboss.ejb.plugins.CallValidationInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (CallValidationInterceptor.java:63)
  at org.jboss.ejb.plugins.AbstractTxInterceptor.invokeNext(Lorg/jboss/invocation/Invocation;Z)Ljava/lang/Object; (AbstractTxInterceptor.java:121)
  at org.jboss.ejb.plugins.TxInterceptorCMT.runWithTransactions(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (TxInterceptorCMT.java:378)
  at org.jboss.ejb.plugins.TxInterceptorCMT.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (TxInterceptorCMT.java:181)
  at org.jboss.ejb.plugins.SecurityInterceptor.process(Lorg/jboss/invocation/Invocation;Z)Ljava/lang/Object; (SecurityInterceptor.java:228)
  at org.jboss.ejb.plugins.SecurityInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (SecurityInterceptor.java:211)
  at org.jboss.ejb.plugins.security.PreSecurityInterceptor.process(Lorg/jboss/invocation/Invocation;Z)Ljava/lang/Object; (PreSecurityInterceptor.java:97)
  at org.jboss.ejb.plugins.security.PreSecurityInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (PreSecurityInterceptor.java:81)
  at org.jboss.ejb.plugins.LogInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (LogInterceptor.java:205)
  at org.jboss.ejb.plugins.ProxyFactoryFinderInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (ProxyFactoryFinderInterceptor.java:138)
  at org.jboss.ejb.SessionContainer.internalInvoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (SessionContainer.java:650)
  at org.jboss.ejb.Container.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (Container.java:1092)
  at org.jboss.ejb.plugins.local.BaseLocalProxyFactory.invoke(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object; (BaseLocalProxyFactory.java:436)
  at org.jboss.ejb.plugins.local.StatelessSessionProxy.invoke(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object; (StatelessSessionProxy.java:103)
  at $Proxy289.doSupports(Lcom/adobe/idp/dsc/transaction/TransactionDefinition;Lcom/adobe/idp/dsc/transaction/TransactionCallback;)Ljava/lang/Object; (Unknown Source)
  at com.adobe.idp.dsc.transaction.impl.ejb.EjbTransactionProvider.execute(Lcom/adobe/idp/dsc/transaction/TransactionDefinition;Lcom/adobe/idp/dsc/transaction/TransactionCallback;)Ljava/lang/Object; (EjbTransactionProvider.java:104)

Answer 1

您的堆栈跟踪显示了UnixFileSystem.list（文件）方法，这是一个本机方法，它正在创建一个用于存储文件名的字符串数组。剩下的问题是为什么它要创建一个大小为1600万的数组。该方法从大小为 16 的数组开始，一旦目录扫描的迭代次数超过数组大小，该方法将加倍。因此，现在的迭代次数在800万到1600万之间。您要么在该目录中拥有难以置信的文件数量，要么在该本机代码中的循环终止条件中存在问题。