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activiti explorer with mysql

Question asked by aemro on Aug 13, 2013
Latest reply on Aug 16, 2013 by aemro
Just afte i set up activiti Explorer with mysql database, some times it hangs, generating the following error. I tried it with the out of the box examples downloaded with the package.   I have used the latest version 5.13. 

AM org.apache.catalina.startup.Catalina start
INFO: Server startup in 9338 ms
com.vaadin.event.ListenerMethod$MethodException: Invocation of method valueChange in org.activiti.explorer.ui.task.TaskPage$1 failed.
        at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:530)
        at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:164)
        at com.vaadin.ui.AbstractComponent.fireEvent(AbstractComponent.java:1219)
        at com.vaadin.ui.AbstractField.fireValueChange(AbstractField.java:897)
        at com.vaadin.ui.AbstractField.setValue(AbstractField.java:529)
        at com.vaadin.ui.AbstractSelect.setValue(AbstractSelect.java:676)
        at com.vaadin.ui.AbstractSelect.setValue(AbstractSelect.java:645)
        at com.vaadin.ui.Table.setValue(Table.java:3572)
        at com.vaadin.ui.AbstractSelect.select(AbstractSelect.java:1422)
        at org.activiti.explorer.ui.AbstractTablePage.selectElement(AbstractTablePage.java:81)
        at org.activiti.explorer.ui.task.TaskPage.initUi(TaskPage.java:70)
        at org.activiti.explorer.ui.AbstractPage.attach(AbstractPage.java:43)
        at com.vaadin.ui.AbstractComponent.setParent(AbstractComponent.java:560)
        at com.vaadin.ui.AbstractComponentContainer.addComponent(AbstractComponentContainer.java:211)
        at com.vaadin.ui.CssLayout.addComponent(CssLayout.java:95)
        at org.activiti.explorer.ui.mainlayout.MainLayout.setMainContent(MainLayout.java:58)
        at org.activiti.explorer.ui.MainWindow.switchView(MainWindow.java:79)
        at org.activiti.explorer.DefaultViewManager.switchView(DefaultViewManager.java:342)
        at org.activiti.explorer.DefaultViewManager.showInboxPage(DefaultViewManager.java:172)
        at org.activiti.explorer.DefaultViewManager.showDefaultPage(DefaultViewManager.java:90)
        at org.activiti.explorer.ui.login.LoginPage$ActivitiLoginListener.onLogin(LoginPage.java:102)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)
        at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:510)
        at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:164)
        at com.vaadin.ui.AbstractComponent.fireEvent(AbstractComponent.java:1219)
        at com.vaadin.ui.LoginForm$2.handleParameters(LoginForm.java:103)
        at com.vaadin.ui.Window.handleParameters(Window.java:515)
        at com.vaadin.terminal.gwt.server.AbstractApplicationServlet.service(AbstractApplicationServlet.java:528)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.activiti.explorer.filter.ExplorerFilter.doFilter(ExplorerFilter.java:44)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)
        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
        at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.NullPointerException
        at org.activiti.engine.impl.cmd.GetIdentityLinksForTaskCmd.execute(GetIdentityLinksForTaskCmd.java:47)
        at org.activiti.engine.impl.cmd.GetIdentityLinksForTaskCmd.execute(GetIdentityLinksForTaskCmd.java:31)
        at org.activiti.engine.impl.interceptor.CommandExecutorImpl.execute(CommandExecutorImpl.java:24)
        at org.activiti.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:61)
        at org.activiti.spring.SpringTransactionInterceptor$1.doInTransaction(SpringTransactionInterceptor.java:42)
        at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:130)
        at org.activiti.spring.SpringTransactionInterceptor.execute(SpringTransactionInterceptor.java:40)
        at org.activiti.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:31)
        at org.activiti.engine.impl.TaskServiceImpl.getIdentityLinksForTask(TaskServiceImpl.java:154)
        at org.activiti.explorer.ui.task.TaskInvolvedPeopleComponent.initInvolvedPeople(TaskInvolvedPeopleComponent.java:183)
        at org.activiti.explorer.ui.task.TaskInvolvedPeopleComponent.populatePeopleGrid(TaskInvolvedPeopleComponent.java:151)
        at org.activiti.explorer.ui.task.TaskInvolvedPeopleComponent.initPeopleGrid(TaskInvolvedPeopleComponent.java:145)
        at org.activiti.explorer.ui.task.TaskInvolvedPeopleComponent.initUi(TaskInvolvedPeopleComponent.java:82)
        at org.activiti.explorer.ui.task.TaskInvolvedPeopleComponent.<init>(TaskInvolvedPeopleComponent.java:73)
        at org.activiti.explorer.ui.task.TaskDetailPanel.initPeopleDetails(TaskDetailPanel.java:283)
        at org.activiti.explorer.ui.task.TaskDetailPanel.init(TaskDetailPanel.java:115)
        at org.activiti.explorer.ui.task.TaskDetailPanel.attach(TaskDetailPanel.java:99)
        at com.vaadin.ui.AbstractComponent.setParent(AbstractComponent.java:560)
        at com.vaadin.ui.AbstractComponentContainer.addComponent(AbstractComponentContainer.java:211)
        at com.vaadin.ui.GridLayout.addComponent(GridLayout.java:230)
        at org.activiti.explorer.ui.AbstractPage.setDetailComponent(AbstractPage.java:155)
        at org.activiti.explorer.ui.task.TaskPage.access$000(TaskPage.java:44)
        at org.activiti.explorer.ui.task.TaskPage$1.valueChange(TaskPage.java:117)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)
        at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:510)
        … 46 more

ERROR org.springframework.transaction.support.TransactionTemplate  - Application exception overridden by rollback exception
org.apache.ibatis.exceptions.PersistenceException:
### Error querying database.  Cause: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:

** BEGIN NESTED EXCEPTION **

java.net.SocketException
MESSAGE: Software caused connection abort: recv failed

STACKTRACE:

java.net.SocketException: Software caused connection abort: recv failed
        at java.net.SocketInputStream.socketRead0(Native Method)
        at java.net.SocketInputStream.read(SocketInputStream.java:150)
        at java.net.SocketInputStream.read(SocketInputStream.java:121)
        at com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:113)
        at com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:160)
        at com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:188)
        at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1994)
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2411)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2916)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1631)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
        at com.mysql.jdbc.Connection.execSQL(Connection.java:3256)
        at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1313)
        at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:874)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
        at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:56)
        at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:70)
        at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:57)
        at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:259)
        at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:132)
        at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:105)
        at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:81)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:104)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:98)
        at org.activiti.engine.impl.db.DbSqlSession.selectListWithRawParameter(DbSqlSession.java:284)
        at org.activiti.engine.impl.db.DbSqlSession.selectList(DbSqlSession.java:275)
        at org.activiti.engine.impl.db.DbSqlSession.selectList(DbSqlSession.java:270)
        at org.activiti.engine.impl.db.DbSqlSession.selectList(DbSqlSession.java:251)
        at org.activiti.engine.impl.persistence.entity.VariableInstanceEntityManager.findVariableInstancesByTaskId(VariableInstanceEntityManager.java:29)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.loadVariableInstances(TaskEntity.java:233)
        at org.activiti.engine.impl.persistence.entity.VariableScopeImpl.ensureVariableInstancesInitialized(VariableScopeImpl.java:60)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.getVariableInstances(TaskEntity.java:691)
        at org.activiti.engine.impl.persistence.entity.VariableInstanceEntityManager.deleteVariableInstanceByTask(VariableInstanceEntityManager.java:38)
        at org.activiti.engine.impl.persistence.entity.TaskEntityManager.deleteTask(TaskEntityManager.java:64)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.complete(TaskEntity.java:152)
        at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.java:39)
        at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.java:24)
        at org.activiti.engine.impl.cmd.NeedsActiveTaskCmd.execute(NeedsActiveTaskCmd.java:61)
        at org.activiti.engine.impl.interceptor.CommandExecutorImpl.execute(CommandExecutorImpl.java:24)
        at org.activiti.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:61)
        at org.activiti.spring.SpringTransactionInterceptor$1.doInTransaction(SpringTransactionInterceptor.java:42)
        at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:130)
        at org.activiti.spring.SpringTransactionInterceptor.execute(SpringTransactionInterceptor.java:40)
        at org.activiti.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:31)
        at org.activiti.engine.impl.TaskServiceImpl.complete(TaskServiceImpl.java:163)
        at org.activiti.explorer.demo.DemoDataGenerator$1.run(DemoDataGenerator.java:278)
        at java.lang.Thread.run(Thread.java:722)


** END NESTED EXCEPTION **



Last packet sent to the server was 1475441 ms ago.
### The error may exist in org/activiti/db/mapping/entity/VariableInstance.xml
### The error may involve org.activiti.engine.impl.persistence.entity.VariableInstanceEntity.selectVariablesByTaskId-Inline
### The error occurred while setting parameters
### SQL: select * from ACT_RU_VARIABLE where     TASK_ID_ =     ?
### Cause: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:

** BEGIN NESTED EXCEPTION **

java.net.SocketException
MESSAGE: Software caused connection abort: recv failed

STACKTRACE:

java.net.SocketException: Software caused connection abort: recv failed
        at java.net.SocketInputStream.socketRead0(Native Method)
        at java.net.SocketInputStream.read(SocketInputStream.java:150)
        at java.net.SocketInputStream.read(SocketInputStream.java:121)
        at com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:113)
        at com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:160)
        at com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:188)
        at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1994)
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2411)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2916)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1631)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
        at com.mysql.jdbc.Connection.execSQL(Connection.java:3256)
        at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1313)
        at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:874)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
        at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:56)
        at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:70)
        at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:57)
        at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:259)
        at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:132)
        at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:105)
        at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:81)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:104)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:98)
        at org.activiti.engine.impl.db.DbSqlSession.selectListWithRawParameter(DbSqlSession.java:284)
        at org.activiti.engine.impl.db.DbSqlSession.selectList(DbSqlSession.java:275)
        at org.activiti.engine.impl.db.DbSqlSession.selectList(DbSqlSession.java:270)
        at org.activiti.engine.impl.db.DbSqlSession.selectList(DbSqlSession.java:251)
        at org.activiti.engine.impl.persistence.entity.VariableInstanceEntityManager.findVariableInstancesByTaskId(VariableInstanceEntityManager.java:29)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.loadVariableInstances(TaskEntity.java:233)
        at org.activiti.engine.impl.persistence.entity.VariableScopeImpl.ensureVariableInstancesInitialized(VariableScopeImpl.java:60)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.getVariableInstances(TaskEntity.java:691)
        at org.activiti.engine.impl.persistence.entity.VariableInstanceEntityManager.deleteVariableInstanceByTask(VariableInstanceEntityManager.java:38)
        at org.activiti.engine.impl.persistence.entity.TaskEntityManager.deleteTask(TaskEntityManager.java:64)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.complete(TaskEntity.java:152)
        at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.java:39)
        at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.java:24)
        at org.activiti.engine.impl.cmd.NeedsActiveTaskCmd.execute(NeedsActiveTaskCmd.java:61)
        at org.activiti.engine.impl.interceptor.CommandExecutorImpl.execute(CommandExecutorImpl.java:24)
        at org.activiti.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:61)
        at org.activiti.spring.SpringTransactionInterceptor$1.doInTransaction(SpringTransactionInterceptor.java:42)
        at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:130)
        at org.activiti.spring.SpringTransactionInterceptor.execute(SpringTransactionInterceptor.java:40)
        at org.activiti.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:31)
        at org.activiti.engine.impl.TaskServiceImpl.complete(TaskServiceImpl.java:163)
        at org.activiti.explorer.demo.DemoDataGenerator$1.run(DemoDataGenerator.java:278)
        at java.lang.Thread.run(Thread.java:722)


** END NESTED EXCEPTION **



Last packet sent to the server was 1475441 ms ago.
        at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:23)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:107)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:98)
        at org.activiti.engine.impl.db.DbSqlSession.selectListWithRawParameter(DbSqlSession.java:284)
        at org.activiti.engine.impl.db.DbSqlSession.selectList(DbSqlSession.java:275)
        at org.activiti.engine.impl.db.DbSqlSession.selectList(DbSqlSession.java:270)
        at org.activiti.engine.impl.db.DbSqlSession.selectList(DbSqlSession.java:251)
        at org.activiti.engine.impl.persistence.entity.VariableInstanceEntityManager.findVariableInstancesByTaskId(VariableInstanceEntityManager.java:29)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.loadVariableInstances(TaskEntity.java:233)
        at org.activiti.engine.impl.persistence.entity.VariableScopeImpl.ensureVariableInstancesInitialized(VariableScopeImpl.java:60)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.getVariableInstances(TaskEntity.java:691)
        at org.activiti.engine.impl.persistence.entity.VariableInstanceEntityManager.deleteVariableInstanceByTask(VariableInstanceEntityManager.java:38)
        at org.activiti.engine.impl.persistence.entity.TaskEntityManager.deleteTask(TaskEntityManager.java:64)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.complete(TaskEntity.java:152)
        at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.java:39)
        at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.java:24)
        at org.activiti.engine.impl.cmd.NeedsActiveTaskCmd.execute(NeedsActiveTaskCmd.java:61)
        at org.activiti.engine.impl.interceptor.CommandExecutorImpl.execute(CommandExecutorImpl.java:24)
        at org.activiti.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:61)
        at org.activiti.spring.SpringTransactionInterceptor$1.doInTransaction(SpringTransactionInterceptor.java:42)
        at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:130)
        at org.activiti.spring.SpringTransactionInterceptor.execute(SpringTransactionInterceptor.java:40)
        at org.activiti.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:31)
        at org.activiti.engine.impl.TaskServiceImpl.complete(TaskServiceImpl.java:163)
        at org.activiti.explorer.demo.DemoDataGenerator$1.run(DemoDataGenerator.java:278)
        at java.lang.Thread.run(Thread.java:722)
Caused by: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:

** BEGIN NESTED EXCEPTION **

java.net.SocketException
MESSAGE: Software caused connection abort: recv failed

STACKTRACE:

java.net.SocketException: Software caused connection abort: recv failed
        at java.net.SocketInputStream.socketRead0(Native Method)
        at java.net.SocketInputStream.read(SocketInputStream.java:150)
        at java.net.SocketInputStream.read(SocketInputStream.java:121)
        at com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:113)
        at com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:160)
        at com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:188)
        at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1994)
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2411)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2916)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1631)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
        at com.mysql.jdbc.Connection.execSQL(Connection.java:3256)
        at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1313)
        at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:874)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
        at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:56)
        at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:70)
        at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:57)
        at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:259)
        at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:132)
        at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:105)
        at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:81)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:104)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:98)
        at org.activiti.engine.impl.db.DbSqlSession.selectListWithRawParameter(DbSqlSession.java:284)
        at org.activiti.engine.impl.db.DbSqlSession.selectList(DbSqlSession.java:275)
        at org.activiti.engine.impl.db.DbSqlSession.selectList(DbSqlSession.java:270)
        at org.activiti.engine.impl.db.DbSqlSession.selectList(DbSqlSession.java:251)
        at org.activiti.engine.impl.persistence.entity.VariableInstanceEntityManager.findVariableInstancesByTaskId(VariableInstanceEntityManager.java:29)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.loadVariableInstances(TaskEntity.java:233)
        at org.activiti.engine.impl.persistence.entity.VariableScopeImpl.ensureVariableInstancesInitialized(VariableScopeImpl.java:60)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.getVariableInstances(TaskEntity.java:691)
        at org.activiti.engine.impl.persistence.entity.VariableInstanceEntityManager.deleteVariableInstanceByTask(VariableInstanceEntityManager.java:38)
        at org.activiti.engine.impl.persistence.entity.TaskEntityManager.deleteTask(TaskEntityManager.java:64)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.complete(TaskEntity.java:152)
        at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.java:39)
        at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.java:24)
        at org.activiti.engine.impl.cmd.NeedsActiveTaskCmd.execute(NeedsActiveTaskCmd.java:61)
        at org.activiti.engine.impl.interceptor.CommandExecutorImpl.execute(CommandExecutorImpl.java:24)
        at org.activiti.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:61)
        at org.activiti.spring.SpringTransactionInterceptor$1.doInTransaction(SpringTransactionInterceptor.java:42)
        at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:130)
        at org.activiti.spring.SpringTransactionInterceptor.execute(SpringTransactionInterceptor.java:40)
        at org.activiti.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:31)
        at org.activiti.engine.impl.TaskServiceImpl.complete(TaskServiceImpl.java:163)
        at org.activiti.explorer.demo.DemoDataGenerator$1.run(DemoDataGenerator.java:278)
        at java.lang.Thread.run(Thread.java:722)


** END NESTED EXCEPTION **



Last packet sent to the server was 1475441 ms ago.
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2622)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2916)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1631)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
        at com.mysql.jdbc.Connection.execSQL(Connection.java:3256)
        at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1313)
        at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:874)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
        at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:56)
        at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:70)
        at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:57)
        at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:259)
        at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:132)
        at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:105)
        at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:81)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:104)
        … 24 more
Exception in thread "Thread-4" org.springframework.transaction.TransactionSystemException: Could not roll back JDBC transaction; nested exception is com.mysql.jdbc.exceptions.MySQLNonTransientConnecti
onException: Connection.close() has already been called. Invalid operation in this state.
        at org.springframework.jdbc.datasource.DataSourceTransactionManager.doRollback(DataSourceTransactionManager.java:285)
        at org.springframework.transaction.support.AbstractPlatformTransactionManager.processRollback(AbstractPlatformTransactionManager.java:845)
        at org.springframework.transaction.support.AbstractPlatformTransactionManager.rollback(AbstractPlatformTransactionManager.java:822)
        at org.springframework.transaction.support.TransactionTemplate.rollbackOnException(TransactionTemplate.java:161)
        at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:134)
        at org.activiti.spring.SpringTransactionInterceptor.execute(SpringTransactionInterceptor.java:40)
        at org.activiti.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:31)
        at org.activiti.engine.impl.TaskServiceImpl.complete(TaskServiceImpl.java:163)
        at org.activiti.explorer.demo.DemoDataGenerator$1.run(DemoDataGenerator.java:278)
        at java.lang.Thread.run(Thread.java:722)
Caused by: com.mysql.jdbc.exceptions.MySQLNonTransientConnectionException: Connection.close() has already been called. Invalid operation in this state.
        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:888)
        at com.mysql.jdbc.Connection.getMutex(Connection.java:3728)
        at com.mysql.jdbc.Connection.rollback(Connection.java:5204)
        at org.apache.commons.dbcp.DelegatingConnection.rollback(DelegatingConnection.java:368)
        at org.apache.commons.

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