Since a week we have the Problem that the j2ee engine is hanging because of locked Threads.
In the thread dumps we can see the thread that locks the other threads:

{code}”SAPEngine_Application_Thread[impl:3]_100″ tid=0x1036b5c50 waiting for monitor entry nid=0x457e prio=5
at Java.lang.Throwable.printStackTrace(Throwable.Java:460)
- waiting to lock<0xfffffffea2c19d58> (a com.SAP.engine.lib.logging.SapLoggingPrintStreamNotThreadSafe), *locked by SAPEngine_Application_Thread[impl:3]_29* at Java.lang.Throwable.printStackTrace(Throwable.Java:451)
at com.SAP.isa.core.RequestProcessor.process(RequestProcessor.Java:421)
at org.apache.struts.action.ActionServlet.process(ActionServlet.Java:1482)
at com.SAP.isa.core.ActionServlet.process(ActionServlet.Java:243)

“SAPEngine_Application_Thread[impl:3]_29″ tid=0x103b36aa0 runnable nid=0×40 prio=5
at Java.security.AccessController.getStackAccessControlContext(Native Method)
at Java.security.AccessController.getContext(AccessController.Java:356)
at com.SAP.engine.services.security.login.SecurityContext.getSession(SecurityContext.Java:4ǡ)
at com.SAP.engine.services.runtimeinfo.RuntimeInfoProvider.reInitProperties(RuntimeInfoProvider.Java:ᐓ)
at com.SAP.tc.logging.LogRecord.setRuntimeProperties(LogRecord.Java:1319)
at com.SAP.tc.logging.LogRecord.(LogRecord.Java:173)
at com.SAP.tc.logging.LogRecord.(LogRecord.Java:126)
at com.SAP.tc.logging.LogRecord.(LogRecord.Java:482)
at com.SAP.tc.logging.LogController.logTInt(LogController.Java:2360)
- locked<0xffffffff4af25d40> (a Java.lang.String)
at com.SAP.tc.logging.LogController.logTInt(LogController.Java:2338)
at com.SAP.tc.logging.Location.logT(Location.Java:473)
at com.SAP.engine.lib.logging.SapLoggingPrintStreamNotThreadSafe.flush(SapLoggingPrintStreamNotThreadSafe.Java᛹)
at com.SAP.engine.lib.logging.SapLoggingPrintStreamNotThreadSafe.println(SapLoggingPrintStreamNotThreadSafe.Java:307)
at Java.lang.Throwable.printStackTrace(Throwable.Java:464)
- locked<0xfffffffea2c19d58> (a com.SAP.engine.lib.logging.SapLoggingPrintStreamNotThreadSafe)
at Java.lang.Throwable.printStackTrace(Throwable.Java:ᒃ)
at com.SAP.isa.core.RequestProcessor.process(RequestProcessor.Java:421)
at org.apache.struts.action.ActionServlet.process(ActionServlet.Java:1482){code}
We also had problems with the ConnectionManager who locked other threads:

“SAPEngine_Application_Thread[impl:3]_101″ tid=0x1041492a0 waiting for monitor entry nid=0x43e2 prio=5
at com.SAP.isa.core.eai.ConnectionManager.getCachedManagedConnection(ConnectionManager.Java:172)
- waiting to lock<0xfffffffeb02b8c30> (a com.SAP.isa.core.eai.ConnectionManager), locked by SAPEngine_Application_Thread[impl:3]_70
at com.SAP.isa.core.eai.ConnectionManager.allocateConnection(ConnectionManager.Java:107)
at com.SAP.isa.core.eai.BackendObjectManagerImpl.createBackendBusinessObject(BackendObjectManagerImpl.Java:170)
- locked<0xfffffffe9791be50> (a com.SAP.isa.core.eai.BackendObjectManagerImpl)
at com.SAP.isa.user.businessobject.UserBase.createBackendService(UserBase.Java:137)
at com.SAP.isa.user.businessobject.UserBase.getBackendService(UserBase.Java:122)
at com.SAP.isa.user.businessobject.UserBase.setLanguage(UserBase.Java:290)
at com.SAP.isa.isacore.action.IsaCoreInitAction.initUser(IsaCoreInitAction.Java:ᘮ)
at com.SAP.isa.isacore.action.IsaCoreInitAction.doPerform(IsaCoreInitAction.Java:369)
at com.SAP.isa.core.BaseAction.execute(BaseAction.Java:212)

“SAPEngine_Application_Thread[impl:3]_70″ tid=0x102721d30 in Object.wait() nid=0x43c3 prio=5
at Java.lang.Object.wait(Native Method)
- waiting on<0xfffffffea491a268> (a Java.lang.Object)
at com.SAP.engine.services.connector.jca.ConnectionHashSet.match(ConnectionHashSet.Java:245)
- locked<0xfffffffea491a268> (a Java.lang.Object)
at com.SAP.engine.services.connector.jca.ConnectionManagerImpl.allocateConnection(ConnectionManagerImpl.Java:307)
at com.SAP.engine.services.dbpool.cci.ConnectionFactoryImpl.getConnection(ConnectionFactoryImpl.Java:51)
at com.SAP.isa.core.eai.sp.jdbc.JDBCManagedConnectionFactory.getPooledConnection(JDBCManagedConnectionFactory.Java:313)
at com.SAP.isa.core.eai.sp.jdbc.JDBCManagedConnectionFactory.getJDBCConnection(JDBCManagedConnectionFactory.Java:237)
at com.SAP.isa.core.eai.sp.jdbc.JDBCManagedConnectionFactory.getConnectionContainer(JDBCManagedConnectionFactory.Java:4Ǧ)
at com.SAP.isa.core.eai.sp.jdbc.JDBCManagedConnectionFactory.createManagedConnection(JDBCManagedConnectionFactory.Java:271)
at com.SAP.isa.core.eai.sp.jdbc.JDBCManagedConnectionFactory.getManagedConnection(JDBCManagedConnectionFactory.Java:149)
at com.SAP.isa.core.eai.ConnectionManager.createManagedConnection(ConnectionManager.Java:228)
- locked<0xfffffffeb02b8c30> (a com.SAP.isa.core.eai.ConnectionManager)
at com.SAP.isa.core.eai.ConnectionManager.allocateConnection(ConnectionManager.Java:111)
at com.SAP.isa.core.eai.BackendObjectManagerImpl.createBackendBusinessObject(BackendObjectManagerImpl.Java:170)
- locked<0xfffffffe7770eeb0> (a com.SAP.isa.core.eai.BackendObjectManagerImpl)

Netweaver Consultant, needs help regarding “J2EE Engine 7.01 Threads are locked “