Dealing with java lang OutOfMemoryError PermGen space error

Question

Recently I ran into this error in my web application      java lang OutOfMemoryError  PermGen space   It s a typical Hibernate JPA   IceFaces JSF application running on Tomcat 6 and JDK 1 6  Apparently this can occur after redeploying an application a few times   What causes it and what can be done to avoid it  How do I fix the problem

User · Answer

App server PermGen errors that happen after multiple deployments are most likely caused by references held by the container into your old apps' classloaders. For example, using a custom log level class will cause references to be held by the app server's classloader. You can detect these inter-classloader leaks by using modern (JDK6+) JVM analysis tools such as jmap and jhat to look at which classes continue to be held in your app, and redesigning or eliminating their use. Usual suspects are databases, loggers, and other base-framework-level libraries.

See Classloader leaks: the dreaded "java.lang.OutOfMemoryError: PermGen space" exception, and especially its followup post.

User · Answer

Use the command line parameter -XX MaxPermSize 128m for a Sun JVM  obviously substituting 128 for whatever size you need

User · Answer

The solution was to add these flags to JVM command line when Tomcat is started   -XX  CMSClassUnloadingEnabled -XX  CMSPermGenSweepingEnabled   You can do that by shutting down the tomcat service  then going into the Tomcat bin directory and running tomcat6w exe  Under the  Java  tab  add the arguments to the  Java Options  box  Click  OK  and then restart the service   If you get an error the specified service does not exist as an installed service you should run   tomcat6w   ES  servicename   where servicename is the name of the server as viewed in services msc  Source  orx s comment on Eric s Agile Answers

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I run into exactly the same problem  but unfortunately none of the suggested solutions really worked for me  The problem did not happen during deployment  and I was neither doing any hot deployments   In my case the problem occurred every time at the same point during the execution of my web-application  while connecting  via hibernate  to the database   This link  also mentioned earlier  did provide enough insides to resolve the problem  Moving the jdbc- mysql -driver out of the WEB-INF and into the jre lib ext  folder seems to have solved the problem  This is not the ideal solution  since upgrading to a newer JRE would require you to reinstall the driver  Another candidate that could cause similar problems is log4j  so you might want to move that one as well

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I ve been butting my head against this problem while deploying and undeploying a complex web application too  and thought I d add an explanation and my solution   When I deploy an application on Apache Tomcat  a new ClassLoader is created for that app  The ClassLoader is then used to load all the application s classes  and on undeploy  everything s supposed to go away nicely  However  in reality it s not quite as simple   One or more of the classes created during the web application s life holds a static reference which  somewhere along the line  references the ClassLoader  As the reference is originally static  no amount of garbage collecting will clean this reference up - the ClassLoader  and all the classes it s loaded  are here to stay   And after a couple of redeploys  we encounter the OutOfMemoryError   Now this has become a fairly serious problem  I could make sure that Tomcat is restarted after each redeploy  but that takes down the entire server  rather than just the application being redeployed  which is often not feasible    So instead I ve put together a solution in code  which works on Apache Tomcat 6 0  I ve not tested on any other application servers  and must stress that this is very likely not to work without modification on any other application server   I d also like to say that personally I hate this code  and that nobody should be using this as a  quick fix  if the existing code can be changed to use proper shutdown and cleanup methods  The only time this should be used is if there s an external library your code is dependent on  In my case  it was a RADIUS client  that doesn t provide a means to clean up its own static references   Anyway  on with the code  This should be called at the point where the application is undeploying - such as a servlet s destroy method or  the better approach  a ServletContextListener s contextDestroyed method     Get a list of all classes loaded by the current webapp classloader WebappClassLoader classLoader    WebappClassLoader  getClass   getClassLoader    Field classLoaderClassesField   null  Class clazz   WebappClassLoader class  while  classLoaderClassesField    null  amp  amp  clazz    null        try           classLoaderClassesField   clazz getDeclaredField  classes          catch  Exception exception              do nothing           clazz   clazz getSuperclass      classLoaderClassesField setAccessible true    List classes   new ArrayList  Vector classLoaderClassesField get classLoader     for  Object o   classes        Class c    Class o        Make sure you identify only the packages that are holding references to the classloader        Allowing this code to clear all static references will result in all sorts       of horrible things  like java segfaulting       if  c getName   startsWith  com whatever                Kill any static references within all these classes          for  Field f   c getDeclaredFields                  if  Modifier isStatic f getModifiers                         amp  amp   Modifier isFinal f getModifiers                         amp  amp   f getType   isPrimitive                      try                       f setAccessible true                       f set null  null                     catch  Exception exception                          Log the exception                                                    classes clear

User · Answer

App server PermGen errors that happen after multiple deployments are most likely caused by references held by the container into your old apps' classloaders. For example, using a custom log level class will cause references to be held by the app server's classloader. You can detect these inter-classloader leaks by using modern (JDK6+) JVM analysis tools such as jmap and jhat to look at which classes continue to be held in your app, and redesigning or eliminating their use. Usual suspects are databases, loggers, and other base-framework-level libraries.

See Classloader leaks: the dreaded "java.lang.OutOfMemoryError: PermGen space" exception, and especially its followup post.

User · Answer

You better try -XX MaxPermSize 128M rather than -XX MaxPermGen 128M    I can not tell the precise use of this memory pool  but it have to do with the number of classes loaded into the JVM   Thus enabling class unloading for tomcat can resolve the problem   If your applications generates and compiles classes on the run it is more likely to need a memory pool bigger than the default

User · Answer

Use the command line parameter -XX MaxPermSize 128m for a Sun JVM  obviously substituting 128 for whatever size you need

User · Answer

Common mistakes people make is thinking that heap space and permgen space are same  which is not at all true   You could have lot of space remaining in the heap but still can run out of memory in permgen    Common causes of OutofMemory in PermGen is ClassLoader  Whenever a class is loaded into JVM  all its meta data  along with Classloader  is kept on PermGen area and they will be garbage collected when the Classloader which loaded them is ready for garbage collection  In Case Classloader has a memory leak than all classes loaded by it will remain in memory and cause permGen outofmemory once you repeat it a couple of times   The classical example is Java lang OutOfMemoryError PermGen Space in Tomcat    Now there are two ways to solve this  1  Find the cause of Memory Leak or if there is any memory leak  2  Increase size of PermGen Space by using JVM param -XX MaxPermSize and -XX PermSize   You can also check 2 Solution of Java lang OutOfMemoryError in Java for more details

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The simplest answer these days is to use Java 8     It no longer reserves memory exclusively for PermGen space  allowing the PermGen memory to co-mingle with the regular memory pool   Keep in mind that you will have to remove all non-standard -XXPermGen        JVM startup parameters if you don t want Java 8 to complain that they don t do anything

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You can also solve this problem by doing a   rm -rf  lt tomcat-dir gt  work    lt tomcat-dir gt  temp     Clearing out the work and temp directories makes Tomcat do a clean startup

User · Answer

1  Increasing the PermGen Memory Size  The first thing one can do is to make the size of the permanent generation heap space bigger  This cannot be done with the usual    Xms set initial heap size  and    Xmx set maximum heap size  JVM arguments  since as mentioned  the permanent generation heap space is entirely separate from the regular Java Heap space   and these arguments set the space for this regular Java heap space  However  there are similar arguments which can be used at least with the Sun OpenJDK jvms  to make the size of the permanent generation heap bigger    -XX MaxPermSize 128m   Default is 64m   2  Enable Sweeping  Another way to take care of that for good is to allow classes to be unloaded so your PermGen never runs out   -XX  CMSClassUnloadingEnabled -XX  CMSPermGenSweepingEnabled   Stuff like that worked magic for me in the past  One thing though  there   s a significant performance trade off in using those  since permgen sweeps will  make like an extra 2 requests for every request you make or something along those lines  You   ll need to balance your use with the tradeoffs   You can find the details of this error   http   faisalbhagat blogspot com 2014 09 java-outofmemoryerror-permgen html

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The configuration of the memory depends on the nature of your app   What are you doing   What s the amount of transactions precessed   How much data are you loading   etc   etc   etc  Probably you could profile your app and start cleaning up some modules from your app       Apparently this can occur after redeploying an application a few times   Tomcat has hot deploy but it consumes memory  Try restarting your container once in a while   Also you will need to know the amount of memory needed to run in production mode  this seems a good time for that research

User · Answer

Common mistakes people make is thinking that heap space and permgen space are same  which is not at all true   You could have lot of space remaining in the heap but still can run out of memory in permgen    Common causes of OutofMemory in PermGen is ClassLoader  Whenever a class is loaded into JVM  all its meta data  along with Classloader  is kept on PermGen area and they will be garbage collected when the Classloader which loaded them is ready for garbage collection  In Case Classloader has a memory leak than all classes loaded by it will remain in memory and cause permGen outofmemory once you repeat it a couple of times   The classical example is Java lang OutOfMemoryError PermGen Space in Tomcat    Now there are two ways to solve this  1  Find the cause of Memory Leak or if there is any memory leak  2  Increase size of PermGen Space by using JVM param -XX MaxPermSize and -XX PermSize   You can also check 2 Solution of Java lang OutOfMemoryError in Java for more details

User · Answer

They Say that the latest rev of Tomcat  6 0 28 or 6 0 29  handles the task of redeploying servlets much better

User · Answer

The simplest answer these days is to use Java 8     It no longer reserves memory exclusively for PermGen space  allowing the PermGen memory to co-mingle with the regular memory pool   Keep in mind that you will have to remove all non-standard -XXPermGen        JVM startup parameters if you don t want Java 8 to complain that they don t do anything

User · Answer

First step in such case is to check whether the GC is allowed to unload classes from PermGen  The standard JVM is rather conservative in this regard     classes are born to live forever  So once loaded  classes stay in memory even if no code is using them anymore  This can become a problem when the application creates lots of classes dynamically and the generated classes are not needed for longer periods  In such a case  allowing the JVM to unload class definitions can be helpful  This can be achieved by adding just one configuration parameter to your startup scripts   -XX  CMSClassUnloadingEnabled   By default this is set to false and so to enable this you need to explicitly set the following option in Java options  If you enable CMSClassUnloadingEnabled  GC will sweep PermGen too and remove classes which are no longer used  Keep in mind that this option will work only when UseConcMarkSweepGC is also enabled using the below option  So when running ParallelGC or  God forbid  Serial GC  make sure you have set your GC to CMS by specifying   -XX  UseConcMarkSweepGC

User · Answer

Increasing Permanent Generation size or tweaking GC parameters will NOT help if you have a real memory leak  If your application or some 3rd party library it uses  leaks class loaders the only real and permanent solution is to find this leak and fix it  There are number of tools that can help you  one of the recent is Plumbr  which has just released a new version with the required capabilities

User · Answer

Also if you are using log4j in your webapp  check this paragraph in log4j documentation   It seems that if you are using PropertyConfigurator configureAndWatch  log4j properties    you cause memory leaks when you undeploy your webapp

User · Answer

I ve been butting my head against this problem while deploying and undeploying a complex web application too  and thought I d add an explanation and my solution   When I deploy an application on Apache Tomcat  a new ClassLoader is created for that app  The ClassLoader is then used to load all the application s classes  and on undeploy  everything s supposed to go away nicely  However  in reality it s not quite as simple   One or more of the classes created during the web application s life holds a static reference which  somewhere along the line  references the ClassLoader  As the reference is originally static  no amount of garbage collecting will clean this reference up - the ClassLoader  and all the classes it s loaded  are here to stay   And after a couple of redeploys  we encounter the OutOfMemoryError   Now this has become a fairly serious problem  I could make sure that Tomcat is restarted after each redeploy  but that takes down the entire server  rather than just the application being redeployed  which is often not feasible    So instead I ve put together a solution in code  which works on Apache Tomcat 6 0  I ve not tested on any other application servers  and must stress that this is very likely not to work without modification on any other application server   I d also like to say that personally I hate this code  and that nobody should be using this as a  quick fix  if the existing code can be changed to use proper shutdown and cleanup methods  The only time this should be used is if there s an external library your code is dependent on  In my case  it was a RADIUS client  that doesn t provide a means to clean up its own static references   Anyway  on with the code  This should be called at the point where the application is undeploying - such as a servlet s destroy method or  the better approach  a ServletContextListener s contextDestroyed method     Get a list of all classes loaded by the current webapp classloader WebappClassLoader classLoader    WebappClassLoader  getClass   getClassLoader    Field classLoaderClassesField   null  Class clazz   WebappClassLoader class  while  classLoaderClassesField    null  amp  amp  clazz    null        try           classLoaderClassesField   clazz getDeclaredField  classes          catch  Exception exception              do nothing           clazz   clazz getSuperclass      classLoaderClassesField setAccessible true    List classes   new ArrayList  Vector classLoaderClassesField get classLoader     for  Object o   classes        Class c    Class o        Make sure you identify only the packages that are holding references to the classloader        Allowing this code to clear all static references will result in all sorts       of horrible things  like java segfaulting       if  c getName   startsWith  com whatever                Kill any static references within all these classes          for  Field f   c getDeclaredFields                  if  Modifier isStatic f getModifiers                         amp  amp   Modifier isFinal f getModifiers                         amp  amp   f getType   isPrimitive                      try                       f setAccessible true                       f set null  null                     catch  Exception exception                          Log the exception                                                    classes clear

User · Answer

I was having similar issue  Mine is JDK 7   Maven 3 0 2   Struts 2 0   Google GUICE dependency injection based project   Whenever i tried running mvn clean package command  it was showing following error and  BUILD FAILURE  occured      org apache maven surefire util SurefireReflectionException  java lang reflect InvocationTargetException  nested exception is java lang reflect InvocationTargetException  null   java lang reflect InvocationTargetException    Caused by  java lang OutOfMemoryError  PermGen space   I tried all the above useful tips and tricks but unfortunately none worked for me  What worked for me is described step by step below       Go to your pom xml Search for   lt artifactId gt maven-surefire-plugin lt  artifactId gt  Add a new  lt configuration gt  element and then  lt argLine gt  sub element in which pass -Xmx512m -XX MaxPermSize 256m as shown below         lt configuration gt       lt argLine gt -Xmx512m -XX MaxPermSize 256m lt  argLine gt     lt  configuration gt   Hope it helps  happy programming

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The only way that worked for me was with the JRockit JVM  I have MyEclipse 8 6   The JVM s heap stores all the objects generated by a running Java program  Java uses the new operator to create objects  and memory for new objects is allocated on the heap at run time  Garbage collection is the mechanism of automatically freeing up the memory contained by the objects that are no longer referenced by the program

User · Answer

Open tomcat7w from Tomcat s bin directory or type Monitor Tomcat in start menu   a tabbed window opens with various service information   In the Java Options text area append this line   -XX MaxPermSize 128m  Set Initial Memory Pool to 1024  optional   Set Maximum Memory Pool to 1024  optional   Click Ok  Restart the Tomcat service

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Try -XX MaxPermSize 256m and if it persists  try -XX MaxPermSize 512m

User · Answer

Open tomcat7w from Tomcat s bin directory or type Monitor Tomcat in start menu   a tabbed window opens with various service information   In the Java Options text area append this line   -XX MaxPermSize 128m  Set Initial Memory Pool to 1024  optional   Set Maximum Memory Pool to 1024  optional   Click Ok  Restart the Tomcat service

User · Answer

I was having similar issue  Mine is JDK 7   Maven 3 0 2   Struts 2 0   Google GUICE dependency injection based project   Whenever i tried running mvn clean package command  it was showing following error and  BUILD FAILURE  occured      org apache maven surefire util SurefireReflectionException  java lang reflect InvocationTargetException  nested exception is java lang reflect InvocationTargetException  null   java lang reflect InvocationTargetException    Caused by  java lang OutOfMemoryError  PermGen space   I tried all the above useful tips and tricks but unfortunately none worked for me  What worked for me is described step by step below       Go to your pom xml Search for   lt artifactId gt maven-surefire-plugin lt  artifactId gt  Add a new  lt configuration gt  element and then  lt argLine gt  sub element in which pass -Xmx512m -XX MaxPermSize 256m as shown below         lt configuration gt       lt argLine gt -Xmx512m -XX MaxPermSize 256m lt  argLine gt     lt  configuration gt   Hope it helps  happy programming

User · Answer

I had the problem we are talking about here  my scenario is eclipse-helios   tomcat   jsf and what you were doing is making a deploy a simple application to tomcat  I was showing the same problem here  solved it as follows    In eclipse go to servers tab double click on the registered server in my case tomcat 7 0  it opens my file server General registration information  On the section  General Information  click on the link  Open launch configuration    this opens the execution of server options in the Arguments tab in VM arguments added in the end these two entries  -XX  MaxPermSize   512m -XX  PermSize   512m   and ready

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I have a combination of Hibernate Eclipse RCP  tried using -XX MaxPermSize 512m and -XX PermSize 512m and it seems to be working for me

User · Answer

You can also solve this problem by doing a   rm -rf  lt tomcat-dir gt  work    lt tomcat-dir gt  temp     Clearing out the work and temp directories makes Tomcat do a clean startup

User · Answer

The java lang OutOfMemoryError  PermGen space message indicates that the Permanent Generation   s area in memory is exhausted    Any Java applications is allowed to use a limited amount of memory  The exact amount of memory your particular application can use is specified during application startup   Java memory is separated into different regions which can be seen in the following image     Metaspace  A new memory space is born  The JDK 8 HotSpot JVM is now using native memory for the representation of class metadata and is called Metaspace  similar to the Oracle JRockit and IBM JVM s   The good news is that it means no more java lang OutOfMemoryError  PermGen space problems and no need for you to tune and monitor this memory space anymore using Java 8 Download or higher

User · Answer

I added -XX  MaxPermSize   128m  you can experiment which works best  to VM Arguments as I m using eclipse ide  In most of JVM  default PermSize is around 64MB which runs out of memory if there are too many classes or huge number of Strings in the project   For eclipse  it is also described at answer   STEP 1   Double Click on the tomcat server at Servers Tab    STEP 2   Open launch Conf and add -XX  MaxPermSize   128m to the end of existing VM arguements

User · Answer

Set -XX PermSize 64m -XX MaxPermSize 128m  Later on you may also try increasing MaxPermSize  Hope it ll work  The same works for me  Setting only MaxPermSize didn t worked for me

User · Answer

I had the problem we are talking about here  my scenario is eclipse-helios   tomcat   jsf and what you were doing is making a deploy a simple application to tomcat  I was showing the same problem here  solved it as follows    In eclipse go to servers tab double click on the registered server in my case tomcat 7 0  it opens my file server General registration information  On the section  General Information  click on the link  Open launch configuration    this opens the execution of server options in the Arguments tab in VM arguments added in the end these two entries  -XX  MaxPermSize   512m -XX  PermSize   512m   and ready

User · Answer

If any one is struggling with the same error in netbeans  then here is how I fixed it   In Netbeans   Go to services tab --  Right on server -- Choose properties --  go to platform tab -- Inside vm options type -Xms1024m  In my case  I have given -Xms4096m  Here is the screenshot

User · Answer

The only way that worked for me was with the JRockit JVM  I have MyEclipse 8 6   The JVM s heap stores all the objects generated by a running Java program  Java uses the new operator to create objects  and memory for new objects is allocated on the heap at run time  Garbage collection is the mechanism of automatically freeing up the memory contained by the objects that are no longer referenced by the program

User · Answer

The solution was to add these flags to JVM command line when Tomcat is started   -XX  CMSClassUnloadingEnabled -XX  CMSPermGenSweepingEnabled   You can do that by shutting down the tomcat service  then going into the Tomcat bin directory and running tomcat6w exe  Under the  Java  tab  add the arguments to the  Java Options  box  Click  OK  and then restart the service   If you get an error the specified service does not exist as an installed service you should run   tomcat6w   ES  servicename   where servicename is the name of the server as viewed in services msc  Source  orx s comment on Eric s Agile Answers

User · Answer

Use the command line parameter -XX MaxPermSize 128m for a Sun JVM  obviously substituting 128 for whatever size you need

User · Answer

Assigning Tomcat more memory is NOT the proper solution   The correct solution is to do a cleanup after the context is destroyed and recreated  the hot deploy   The solution is to stop the memory leaks   If your Tomcat Webapp Server is telling you that failed to unregister drivers  JDBC   then unregister them  This will stop the memory leaks    You can create a ServletContextListener and configure it in your web xml  Here is a sample ServletContextListener   import java sql Driver  import java sql DriverManager  import java sql SQLException  import java util Enumeration   import javax servlet ServletContextEvent  import javax servlet ServletContextListener   import org apache log4j Logger   import com mysql jdbc AbandonedConnectionCleanupThread               author alejandro tkachuk   calculistik com        public class AppContextListener implements ServletContextListener        private static final Logger logger   Logger getLogger AppContextListener class         Override     public void contextInitialized ServletContextEvent arg0            logger info  AppContextListener started                Override     public void contextDestroyed ServletContextEvent arg0            logger info  AppContextListener destroyed                manually unregister the JDBC drivers         Enumeration lt Driver gt  drivers   DriverManager getDrivers            while  drivers hasMoreElements                  Driver driver   drivers nextElement                try                   DriverManager deregisterDriver driver                   logger info String format  Unregistering jdbc driver   s   driver                  catch  SQLException e                    logger info String format  Error unregistering driver  s   driver   e                                        manually shutdown clean up threads         try               AbandonedConnectionCleanupThread shutdown                logger info  Shutting down AbandonedConnectionCleanupThread              catch  InterruptedException e                logger warn  SEVERE problem shutting down AbandonedConnectionCleanupThread     e               e printStackTrace                                And here you configure it in your web xml    lt listener gt       lt listener-class gt          com calculistik mediweb context AppContextListener       lt  listener-class gt   lt  listener gt

User · Answer

Perm gen space error occurs due to the use of large space rather then jvm provided space to executed the code    The best solution for this problem in UNIX operating systems is to change some configuration on the bash file  The following steps solve the problem   Run command gedit  bashrc on terminal   Create JAVA OTPS variable with following value   export JAVA OPTS  -XX PermSize 256m -XX MaxPermSize 512m    Save the bash file  Run command exec bash on the terminal  Restart the server   I hope this approach will work on your problem  If you use a Java version lower than 8 this issue occurs sometimes  But if you use Java 8 the problem never occurs

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If any one is struggling with the same error in netbeans  then here is how I fixed it   In Netbeans   Go to services tab --  Right on server -- Choose properties --  go to platform tab -- Inside vm options type -Xms1024m  In my case  I have given -Xms4096m  Here is the screenshot

User · Answer

The solution was to add these flags to JVM command line when Tomcat is started   -XX  CMSClassUnloadingEnabled -XX  CMSPermGenSweepingEnabled   You can do that by shutting down the tomcat service  then going into the Tomcat bin directory and running tomcat6w exe  Under the  Java  tab  add the arguments to the  Java Options  box  Click  OK  and then restart the service   If you get an error the specified service does not exist as an installed service you should run   tomcat6w   ES  servicename   where servicename is the name of the server as viewed in services msc  Source  orx s comment on Eric s Agile Answers

User · Answer

I added -XX  MaxPermSize   128m  you can experiment which works best  to VM Arguments as I m using eclipse ide  In most of JVM  default PermSize is around 64MB which runs out of memory if there are too many classes or huge number of Strings in the project   For eclipse  it is also described at answer   STEP 1   Double Click on the tomcat server at Servers Tab    STEP 2   Open launch Conf and add -XX  MaxPermSize   128m to the end of existing VM arguements

User · Answer

The java lang OutOfMemoryError  PermGen space message indicates that the Permanent Generation   s area in memory is exhausted    Any Java applications is allowed to use a limited amount of memory  The exact amount of memory your particular application can use is specified during application startup   Java memory is separated into different regions which can be seen in the following image     Metaspace  A new memory space is born  The JDK 8 HotSpot JVM is now using native memory for the representation of class metadata and is called Metaspace  similar to the Oracle JRockit and IBM JVM s   The good news is that it means no more java lang OutOfMemoryError  PermGen space problems and no need for you to tune and monitor this memory space anymore using Java 8 Download or higher

User · Answer

In case you are getting this in the eclipse IDE  even after setting the parameters  --launcher XXMaxPermSize  -XX MaxPermSize  etc  still if you are getting the same error  it most likely is that the eclipse is using a buggy version of JRE which would have been installed by some third party applications and set to default  These buggy versions do not pick up the PermSize parameters and so no matter whatever you set  you still keep getting these memory errors  So  in your eclipse ini add the following parameters     -vm  lt path to the right JRE directory gt   lt name of javaw executable gt    Also make sure you set the default JRE in the preferences in the eclipse to the correct version of java

User · Answer

Assigning Tomcat more memory is NOT the proper solution   The correct solution is to do a cleanup after the context is destroyed and recreated  the hot deploy   The solution is to stop the memory leaks   If your Tomcat Webapp Server is telling you that failed to unregister drivers  JDBC   then unregister them  This will stop the memory leaks    You can create a ServletContextListener and configure it in your web xml  Here is a sample ServletContextListener   import java sql Driver  import java sql DriverManager  import java sql SQLException  import java util Enumeration   import javax servlet ServletContextEvent  import javax servlet ServletContextListener   import org apache log4j Logger   import com mysql jdbc AbandonedConnectionCleanupThread               author alejandro tkachuk   calculistik com        public class AppContextListener implements ServletContextListener        private static final Logger logger   Logger getLogger AppContextListener class         Override     public void contextInitialized ServletContextEvent arg0            logger info  AppContextListener started                Override     public void contextDestroyed ServletContextEvent arg0            logger info  AppContextListener destroyed                manually unregister the JDBC drivers         Enumeration lt Driver gt  drivers   DriverManager getDrivers            while  drivers hasMoreElements                  Driver driver   drivers nextElement                try                   DriverManager deregisterDriver driver                   logger info String format  Unregistering jdbc driver   s   driver                  catch  SQLException e                    logger info String format  Error unregistering driver  s   driver   e                                        manually shutdown clean up threads         try               AbandonedConnectionCleanupThread shutdown                logger info  Shutting down AbandonedConnectionCleanupThread              catch  InterruptedException e                logger warn  SEVERE problem shutting down AbandonedConnectionCleanupThread     e               e printStackTrace                                And here you configure it in your web xml    lt listener gt       lt listener-class gt          com calculistik mediweb context AppContextListener       lt  listener-class gt   lt  listener gt

User · Answer

App server PermGen errors that happen after multiple deployments are most likely caused by references held by the container into your old apps' classloaders. For example, using a custom log level class will cause references to be held by the app server's classloader. You can detect these inter-classloader leaks by using modern (JDK6+) JVM analysis tools such as jmap and jhat to look at which classes continue to be held in your app, and redesigning or eliminating their use. Usual suspects are databases, loggers, and other base-framework-level libraries.

See Classloader leaks: the dreaded "java.lang.OutOfMemoryError: PermGen space" exception, and especially its followup post.

User · Answer

In case you are getting this in the eclipse IDE  even after setting the parameters  --launcher XXMaxPermSize  -XX MaxPermSize  etc  still if you are getting the same error  it most likely is that the eclipse is using a buggy version of JRE which would have been installed by some third party applications and set to default  These buggy versions do not pick up the PermSize parameters and so no matter whatever you set  you still keep getting these memory errors  So  in your eclipse ini add the following parameters     -vm  lt path to the right JRE directory gt   lt name of javaw executable gt    Also make sure you set the default JRE in the preferences in the eclipse to the correct version of java

User · Answer

Alternatively  you can switch to JRockit which handling permgen differently then sun s jvm   It generally has better performance as well   http   www oracle com technetwork middleware jrockit overview index html

User · Answer

Also if you are using log4j in your webapp  check this paragraph in log4j documentation   It seems that if you are using PropertyConfigurator configureAndWatch  log4j properties    you cause memory leaks when you undeploy your webapp

User · Answer

You better try -XX MaxPermSize 128M rather than -XX MaxPermGen 128M    I can not tell the precise use of this memory pool  but it have to do with the number of classes loaded into the JVM   Thus enabling class unloading for tomcat can resolve the problem   If your applications generates and compiles classes on the run it is more likely to need a memory pool bigger than the default

User · Answer

Increasing Permanent Generation size or tweaking GC parameters will NOT help if you have a real memory leak  If your application or some 3rd party library it uses  leaks class loaders the only real and permanent solution is to find this leak and fix it  There are number of tools that can help you  one of the recent is Plumbr  which has just released a new version with the required capabilities

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The configuration of the memory depends on the nature of your app   What are you doing   What s the amount of transactions precessed   How much data are you loading   etc   etc   etc  Probably you could profile your app and start cleaning up some modules from your app       Apparently this can occur after redeploying an application a few times   Tomcat has hot deploy but it consumes memory  Try restarting your container once in a while   Also you will need to know the amount of memory needed to run in production mode  this seems a good time for that research

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They  are wrong because I m running 6 0 29 and have the same problem even after setting all of the options  As Tim Howland said above  these options only put off the inevitable  They allow me to redeploy 3 times before hitting the error instead of every time I redeploy

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I tried several answers and the only thing what finally did the job was this configuration for the compiler plugin in the pom    lt plugin gt       lt groupId gt org apache maven plugins lt  groupId gt       lt artifactId gt maven-compiler-plugin lt  artifactId gt       lt version gt 2 3 2 lt  version gt       lt configuration gt           lt fork gt true lt  fork gt           lt meminitial gt 128m lt  meminitial gt           lt maxmem gt 512m lt  maxmem gt           lt source gt 1 6 lt  source gt           lt target gt 1 6 lt  target gt           lt  -- prevent PermGen space out of memory exception -- gt           lt  --  lt argLine gt -Xmx512m -XX MaxPermSize 512m lt  argLine gt  -- gt       lt  configuration gt   lt  plugin gt    hope this one helps

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Try -XX MaxPermSize 256m and if it persists  try -XX MaxPermSize 512m

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App server PermGen errors that happen after multiple deployments are most likely caused by references held by the container into your old apps' classloaders. For example, using a custom log level class will cause references to be held by the app server's classloader. You can detect these inter-classloader leaks by using modern (JDK6+) JVM analysis tools such as jmap and jhat to look at which classes continue to be held in your app, and redesigning or eliminating their use. Usual suspects are databases, loggers, and other base-framework-level libraries.

See Classloader leaks: the dreaded "java.lang.OutOfMemoryError: PermGen space" exception, and especially its followup post.

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jrockit resolved this for me as well  however  I noticed that the servlet restart times were much worse  so while it was better in production  it was kind of a drag in development

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I tried several answers and the only thing what finally did the job was this configuration for the compiler plugin in the pom    lt plugin gt       lt groupId gt org apache maven plugins lt  groupId gt       lt artifactId gt maven-compiler-plugin lt  artifactId gt       lt version gt 2 3 2 lt  version gt       lt configuration gt           lt fork gt true lt  fork gt           lt meminitial gt 128m lt  meminitial gt           lt maxmem gt 512m lt  maxmem gt           lt source gt 1 6 lt  source gt           lt target gt 1 6 lt  target gt           lt  -- prevent PermGen space out of memory exception -- gt           lt  --  lt argLine gt -Xmx512m -XX MaxPermSize 512m lt  argLine gt  -- gt       lt  configuration gt   lt  plugin gt    hope this one helps

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Use the command line parameter -XX MaxPermSize 128m for a Sun JVM  obviously substituting 128 for whatever size you need

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jrockit resolved this for me as well  however  I noticed that the servlet restart times were much worse  so while it was better in production  it was kind of a drag in development

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First step in such case is to check whether the GC is allowed to unload classes from PermGen  The standard JVM is rather conservative in this regard     classes are born to live forever  So once loaded  classes stay in memory even if no code is using them anymore  This can become a problem when the application creates lots of classes dynamically and the generated classes are not needed for longer periods  In such a case  allowing the JVM to unload class definitions can be helpful  This can be achieved by adding just one configuration parameter to your startup scripts   -XX  CMSClassUnloadingEnabled   By default this is set to false and so to enable this you need to explicitly set the following option in Java options  If you enable CMSClassUnloadingEnabled  GC will sweep PermGen too and remove classes which are no longer used  Keep in mind that this option will work only when UseConcMarkSweepGC is also enabled using the below option  So when running ParallelGC or  God forbid  Serial GC  make sure you have set your GC to CMS by specifying   -XX  UseConcMarkSweepGC

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Set -XX PermSize 64m -XX MaxPermSize 128m  Later on you may also try increasing MaxPermSize  Hope it ll work  The same works for me  Setting only MaxPermSize didn t worked for me

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They Say that the latest rev of Tomcat  6 0 28 or 6 0 29  handles the task of redeploying servlets much better

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Alternatively  you can switch to JRockit which handling permgen differently then sun s jvm   It generally has better performance as well   http   www oracle com technetwork middleware jrockit overview index html

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Alternatively  you can switch to JRockit which handling permgen differently then sun s jvm   It generally has better performance as well   http   www oracle com technetwork middleware jrockit overview index html

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The solution was to add these flags to JVM command line when Tomcat is started   -XX  CMSClassUnloadingEnabled -XX  CMSPermGenSweepingEnabled   You can do that by shutting down the tomcat service  then going into the Tomcat bin directory and running tomcat6w exe  Under the  Java  tab  add the arguments to the  Java Options  box  Click  OK  and then restart the service   If you get an error the specified service does not exist as an installed service you should run   tomcat6w   ES  servicename   where servicename is the name of the server as viewed in services msc  Source  orx s comment on Eric s Agile Answers

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Alternatively  you can switch to JRockit which handling permgen differently then sun s jvm   It generally has better performance as well   http   www oracle com technetwork middleware jrockit overview index html

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jrockit resolved this for me as well  however  I noticed that the servlet restart times were much worse  so while it was better in production  it was kind of a drag in development

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I have a combination of Hibernate Eclipse RCP  tried using -XX MaxPermSize 512m and -XX PermSize 512m and it seems to be working for me

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I run into exactly the same problem  but unfortunately none of the suggested solutions really worked for me  The problem did not happen during deployment  and I was neither doing any hot deployments   In my case the problem occurred every time at the same point during the execution of my web-application  while connecting  via hibernate  to the database   This link  also mentioned earlier  did provide enough insides to resolve the problem  Moving the jdbc- mysql -driver out of the WEB-INF and into the jre lib ext  folder seems to have solved the problem  This is not the ideal solution  since upgrading to a newer JRE would require you to reinstall the driver  Another candidate that could cause similar problems is log4j  so you might want to move that one as well

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jrockit resolved this for me as well  however  I noticed that the servlet restart times were much worse  so while it was better in production  it was kind of a drag in development

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Perm gen space error occurs due to the use of large space rather then jvm provided space to executed the code    The best solution for this problem in UNIX operating systems is to change some configuration on the bash file  The following steps solve the problem   Run command gedit  bashrc on terminal   Create JAVA OTPS variable with following value   export JAVA OPTS  -XX PermSize 256m -XX MaxPermSize 512m    Save the bash file  Run command exec bash on the terminal  Restart the server   I hope this approach will work on your problem  If you use a Java version lower than 8 this issue occurs sometimes  But if you use Java 8 the problem never occurs

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They  are wrong because I m running 6 0 29 and have the same problem even after setting all of the options  As Tim Howland said above  these options only put off the inevitable  They allow me to redeploy 3 times before hitting the error instead of every time I redeploy

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1  Increasing the PermGen Memory Size  The first thing one can do is to make the size of the permanent generation heap space bigger  This cannot be done with the usual    Xms set initial heap size  and    Xmx set maximum heap size  JVM arguments  since as mentioned  the permanent generation heap space is entirely separate from the regular Java Heap space   and these arguments set the space for this regular Java heap space  However  there are similar arguments which can be used at least with the Sun OpenJDK jvms  to make the size of the permanent generation heap bigger    -XX MaxPermSize 128m   Default is 64m   2  Enable Sweeping  Another way to take care of that for good is to allow classes to be unloaded so your PermGen never runs out   -XX  CMSClassUnloadingEnabled -XX  CMSPermGenSweepingEnabled   Stuff like that worked magic for me in the past  One thing though  there   s a significant performance trade off in using those  since permgen sweeps will  make like an extra 2 requests for every request you make or something along those lines  You   ll need to balance your use with the tradeoffs   You can find the details of this error   http   faisalbhagat blogspot com 2014 09 java-outofmemoryerror-permgen html

[exception] Dealing with "java.lang.OutOfMemoryError: PermGen space" error

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