Class Cast Exception during execution of plugin.

I have a plugin which I am using for updation of the some attributes of WorkItems.
But It is throwing some exception at runtime.
Compilation is successful for the same.

Following is the stack trace for the same :

[ERROR] 2012-07-17 13:25:32.718 - java.lang.ClassCastException@57ae57ae
java.lang.IllegalArgumentException: java.lang.ClassCastException@57ae57ae
    at sun.reflect.GeneratedMethodAccessor226.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.invoke(ExportProxyServiceRecord.java:370)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.access$0(ExportProxyServiceRecord.java:356)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord$ExportedServiceInvocationHandler.invoke(ExportProxyServiceRecord.java:56)
    at $Proxy648.run(Unknown Source)
    at com.ibm.team.process.internal.common.advice.runtime.OperationAdviceManager.runParticipant(OperationAdviceManager.java:1007)
    at com.ibm.team.process.internal.common.advice.runtime.OperationAdviceManager.runParticipants(OperationAdviceManager.java:866)
    at com.ibm.team.process.internal.common.advice.runtime.OperationAdviceManager.advise(OperationAdviceManager.java:299)
    at com.ibm.team.process.internal.common.util.AbstractProcess.doAdvise(AbstractProcess.java:177)
    at com.ibm.team.process.internal.service.ServerProcess.access$1(ServerProcess.java:1)
    at com.ibm.team.process.internal.service.ServerProcess$2.run(ServerProcess.java:137)
    at com.ibm.team.repository.service.internal.TransactionService$2.run(TransactionService.java:204)
    at com.ibm.team.repository.service.internal.rdb.RepositoryDatabase.runTransaction(RepositoryDatabase.java:312)
    at com.ibm.team.repository.service.internal.rdb.RepositoryDatabase.runInTransaction(RepositoryDatabase.java:236)
    at com.ibm.team.repository.service.internal.TransactionService.runInTransaction(TransactionService.java:119)
    at com.ibm.team.repository.service.internal.TransactionService.runInTransaction(TransactionService.java:88)
    at sun.reflect.GeneratedMethodAccessor173.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.invoke(ExportProxyServiceRecord.java:370)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.access$0(ExportProxyServiceRecord.java:356)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord$ExportedServiceInvocationHandler.invoke(ExportProxyServiceRecord.java:56)
    at $Proxy122.runInTransaction(Unknown Source)
    at com.ibm.team.process.internal.service.ProcessService.runInTransaction(ProcessService.java:4117)
    at com.ibm.team.process.internal.service.ProcessService.runInTransaction(ProcessService.java:4124)
    at com.ibm.team.process.internal.service.ServerProcess.adviseAndExecute(ServerProcess.java:135)
    at com.ibm.team.workitem.service.internal.AuditableServerProcess.adviseAndExecute(AuditableServerProcess.java:77)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService.processSave(WorkItemRepositoryService.java:493)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService.save(WorkItemRepositoryService.java:418)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService.save(WorkItemRepositoryService.java:391)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService.access$3(WorkItemRepositoryService.java:387)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService$1.run(WorkItemRepositoryService.java:270)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService$1.run(WorkItemRepositoryService.java:1)
    at com.ibm.team.repository.service.internal.TransactionService$2.run(TransactionService.java:204)
    at com.ibm.team.repository.service.internal.rdb.RepositoryDatabase$Transaction.run(RepositoryDatabase.java:458)
    at com.ibm.team.repository.service.internal.rdb.RepositoryDatabase$1.run(RepositoryDatabase.java:285)
    at com.ibm.team.repository.service.internal.rdb.ConnectionPoolService.withCurrentConnection(ConnectionPoolService.java:379)
    at sun.reflect.GeneratedMethodAccessor73.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.invoke(ExportProxyServiceRecord.java:370)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.access$0(ExportProxyServiceRecord.java:356)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord$ExportedServiceInvocationHandler.invoke(ExportProxyServiceRecord.java:56)
    at $Proxy83.withCurrentConnection(Unknown Source)
    at com.ibm.team.repository.service.internal.rdb.RepositoryDatabase.runTransaction(RepositoryDatabase.java:281)
    at com.ibm.team.repository.service.internal.rdb.RepositoryDatabase.runInTransaction(RepositoryDatabase.java:236)
    at com.ibm.team.repository.service.internal.TransactionService.runInTransaction(TransactionService.java:119)
    at com.ibm.team.repository.service.internal.TransactionService.runInTransaction(TransactionService.java:88)
    at sun.reflect.GeneratedMethodAccessor173.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.invoke(ExportProxyServiceRecord.java:370)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.access$0(ExportProxyServiceRecord.java:356)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord$ExportedServiceInvocationHandler.invoke(ExportProxyServiceRecord.java:56)
    at $Proxy122.runInTransaction(Unknown Source)
    at com.ibm.team.repository.service.AbstractService.runInTransaction(AbstractService.java:947)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService.saveTransaction(WorkItemRepositoryService.java:259)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService.save(WorkItemRepositoryService.java:217)
    at sun.reflect.GeneratedMethodAccessor202.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.invoke(ExportProxyServiceRecord.java:370)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.access$0(ExportProxyServiceRecord.java:356)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord$ExportedServiceInvocationHandler.invoke(ExportProxyServiceRecord.java:56)
    at $Proxy395.save(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor202.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.handleMethod(AbstractTeamServerServlet.java:1285)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.executeMethod(AbstractTeamServerServlet.java:882)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.doPost(AbstractTeamServerServlet.java:672)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.handleRequest2(AbstractTeamServerServlet.java:1871)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.handleRequest(AbstractTeamServerServlet.java:1725)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.access$0(AbstractTeamServerServlet.java:1710)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet$1.service(AbstractTeamServerServlet.java:198)
    at com.ibm.team.repository.internal.service.auth.impl.JAuthHandler.handleRequest(JAuthHandler.java:95)
    at sun.reflect.GeneratedMethodAccessor154.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.invoke(ExportProxyServiceRecord.java:370)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.access$0(ExportProxyServiceRecord.java:356)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord$ExportedServiceInvocationHandler.invoke(ExportProxyServiceRecord.java:56)
    at $Proxy175.handleRequest(Unknown Source)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.service(AbstractTeamServerServlet.java:1578)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
    at org.eclipse.equinox.http.registry.internal.ServletManager$ServletWrapper.service(ServletManager.java:180)
    at org.eclipse.equinox.http.servlet.internal.ServletRegistration.handleRequest(ServletRegistration.java:90)
    at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:111)
    at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:75)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:390)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:939)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:756)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at org.mortbay.jetty.bio.SocketConnector$Connection.run(SocketConnector.java:228)
    at org.mortbay.jetty.security.SslSocketConnector$SslConnection.run(SslSocketConnector.java:680)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
13:25:32,734 [1707369924@qtp-1477203980-46] ERROR com.ibm.team.process.common                         - java.lang.ClassCastException@57ae57ae
java.lang.IllegalArgumentException: java.lang.ClassCastException@57ae57ae
    at sun.reflect.GeneratedMethodAccessor226.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.invoke(ExportProxyServiceRecord.java:370)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.access$0(ExportProxyServiceRecord.java:356)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord$ExportedServiceInvocationHandler.invoke(ExportProxyServiceRecord.java:56)
    at $Proxy648.run(Unknown Source)
    at com.ibm.team.process.internal.common.advice.runtime.OperationAdviceManager.runParticipant(OperationAdviceManager.java:1007)
    at com.ibm.team.process.internal.common.advice.runtime.OperationAdviceManager.runParticipants(OperationAdviceManager.java:866)
    at com.ibm.team.process.internal.common.advice.runtime.OperationAdviceManager.advise(OperationAdviceManager.java:299)
    at com.ibm.team.process.internal.common.util.AbstractProcess.doAdvise(AbstractProcess.java:177)
    at com.ibm.team.process.internal.service.ServerProcess.access$1(ServerProcess.java:1)
    at com.ibm.team.process.internal.service.ServerProcess$2.run(ServerProcess.java:137)
    at com.ibm.team.repository.service.internal.TransactionService$2.run(TransactionService.java:204)
    at com.ibm.team.repository.service.internal.rdb.RepositoryDatabase.runTransaction(RepositoryDatabase.java:312)
    at com.ibm.team.repository.service.internal.rdb.RepositoryDatabase.runInTransaction(RepositoryDatabase.java:236)
    at com.ibm.team.repository.service.internal.TransactionService.runInTransaction(TransactionService.java:119)
    at com.ibm.team.repository.service.internal.TransactionService.runInTransaction(TransactionService.java:88)
    at sun.reflect.GeneratedMethodAccessor173.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.invoke(ExportProxyServiceRecord.java:370)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.access$0(ExportProxyServiceRecord.java:356)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord$ExportedServiceInvocationHandler.invoke(ExportProxyServiceRecord.java:56)
    at $Proxy122.runInTransaction(Unknown Source)
    at com.ibm.team.process.internal.service.ProcessService.runInTransaction(ProcessService.java:4117)
    at com.ibm.team.process.internal.service.ProcessService.runInTransaction(ProcessService.java:4124)
    at com.ibm.team.process.internal.service.ServerProcess.adviseAndExecute(ServerProcess.java:135)
    at com.ibm.team.workitem.service.internal.AuditableServerProcess.adviseAndExecute(AuditableServerProcess.java:77)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService.processSave(WorkItemRepositoryService.java:493)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService.save(WorkItemRepositoryService.java:418)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService.save(WorkItemRepositoryService.java:391)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService.access$3(WorkItemRepositoryService.java:387)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService$1.run(WorkItemRepositoryService.java:270)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService$1.run(WorkItemRepositoryService.java:1)
    at com.ibm.team.repository.service.internal.TransactionService$2.run(TransactionService.java:204)
    at com.ibm.team.repository.service.internal.rdb.RepositoryDatabase$Transaction.run(RepositoryDatabase.java:458)
    at com.ibm.team.repository.service.internal.rdb.RepositoryDatabase$1.run(RepositoryDatabase.java:285)
    at com.ibm.team.repository.service.internal.rdb.ConnectionPoolService.withCurrentConnection(ConnectionPoolService.java:379)
    at sun.reflect.GeneratedMethodAccessor73.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.invoke(ExportProxyServiceRecord.java:370)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.access$0(ExportProxyServiceRecord.java:356)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord$ExportedServiceInvocationHandler.invoke(ExportProxyServiceRecord.java:56)
    at $Proxy83.withCurrentConnection(Unknown Source)
    at com.ibm.team.repository.service.internal.rdb.RepositoryDatabase.runTransaction(RepositoryDatabase.java:281)
    at com.ibm.team.repository.service.internal.rdb.RepositoryDatabase.runInTransaction(RepositoryDatabase.java:236)
    at com.ibm.team.repository.service.internal.TransactionService.runInTransaction(TransactionService.java:119)
    at com.ibm.team.repository.service.internal.TransactionService.runInTransaction(TransactionService.java:88)
    at sun.reflect.GeneratedMethodAccessor173.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.invoke(ExportProxyServiceRecord.java:370)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.access$0(ExportProxyServiceRecord.java:356)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord$ExportedServiceInvocationHandler.invoke(ExportProxyServiceRecord.java:56)
    at $Proxy122.runInTransaction(Unknown Source)
    at com.ibm.team.repository.service.AbstractService.runInTransaction(AbstractService.java:947)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService.saveTransaction(WorkItemRepositoryService.java:259)
    at com.ibm.team.workitem.service.internal.WorkItemRepositoryService.save(WorkItemRepositoryService.java:217)
    at sun.reflect.GeneratedMethodAccessor202.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.invoke(ExportProxyServiceRecord.java:370)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.access$0(ExportProxyServiceRecord.java:356)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord$ExportedServiceInvocationHandler.invoke(ExportProxyServiceRecord.java:56)
    at $Proxy395.save(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor202.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.handleMethod(AbstractTeamServerServlet.java:1285)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.executeMethod(AbstractTeamServerServlet.java:882)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.doPost(AbstractTeamServerServlet.java:672)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.handleRequest2(AbstractTeamServerServlet.java:1871)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.handleRequest(AbstractTeamServerServlet.java:1725)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.access$0(AbstractTeamServerServlet.java:1710)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet$1.service(AbstractTeamServerServlet.java:198)
    at com.ibm.team.repository.internal.service.auth.impl.JAuthHandler.handleRequest(JAuthHandler.java:95)
    at sun.reflect.GeneratedMethodAccessor154.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:618)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.invoke(ExportProxyServiceRecord.java:370)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord.access$0(ExportProxyServiceRecord.java:356)
    at org.eclipse.soda.sat.core.internal.record.ExportProxyServiceRecord$ExportedServiceInvocationHandler.invoke(ExportProxyServiceRecord.java:56)
    at $Proxy175.handleRequest(Unknown Source)
    at com.ibm.team.repository.servlet.AbstractTeamServerServlet.service(AbstractTeamServerServlet.java:1578)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
    at org.eclipse.equinox.http.registry.internal.ServletManager$ServletWrapper.service(ServletManager.java:180)
    at org.eclipse.equinox.http.servlet.internal.ServletRegistration.handleRequest(ServletRegistration.java:90)
    at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:111)
    at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:75)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:390)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:939)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:756)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at org.mortbay.jetty.bio.SocketConnector$Connection.run(SocketConnector.java:228)
    at org.mortbay.jetty.security.SslSocketConnector$SslConnection.run(SslSocketConnector.java:680)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)