Re: kylin org sample query failed as "Error when scan from lower key @ to upper key" after build successfully

[Gqchen]

Thank you very much .  The second : I could get some rows from bbase shell  The First : I have do the same queries twice and it give me the logs: [http-bio-7070-exec-3]:[2016-01-23 12:51:44,710][DEBUG][org.apache.kylin.query.enumerator.CubeEnumerator.queryStorage(CubeEnumerator.java:135)] - query storage... [http-bio-7070-exec-3]:[2016-01-23 12:51:44,711][INFO][org.apache.kylin.storage.hbase.CubeStorageEngine.isExactAggregation(CubeStorageEngine.java:194)] - exactAggregation is true [http-bio-7070-exec-3]:[2016-01-23 12:51:44,712][INFO][org.apache.kylin.storage.hbase.CubeStorageEngine.setThreshold(CubeStorageEngine.java:647)] - Memory budget is set to: 3112295 [http-bio-7070-exec-3]:[2016-01-23 12:51:44,712][INFO][org.apache.kylin.storage.hbase.coprocessor.observer.ObserverEnabler.isCoprocessorBeneficial(ObserverEnabler.java:121)] - Coprocessor is disabled because there is memory hungry count distinct [http-bio-7070-exec-3]:[2016-01-23 12:51:44,716][ERROR][org.apache.kylin.rest.controller.QueryController.doQueryWithCache(QueryController.java:190)] - Exception when execute sql java.sql.SQLException: error while executing SQL "select part_dt, sum(price) as total_selled, count(distinct seller_id) as sellers from kylin_sales group by part_dt order by part_dt LIMIT 10": Error when scan from lower key @ to upper key @��� on table KYLIN_FOBSAT4IR6. at org.apache.calcite.avatica.Helper.createException(Helper.java:41) at org.apache.calcite.avatica.AvaticaStatement.executeInternal(AvaticaStatement.java:112) at org.apache.calcite.avatica.AvaticaStatement.executeQuery(AvaticaStatement.java:130) at org.apache.kylin.rest.service.QueryService.execute(QueryService.java:354) at org.apache.kylin.rest.service.QueryService.queryWithSqlMassage(QueryService.java:268) at org.apache.kylin.rest.service.QueryService.query(QueryService.java:114) at org.apache.kylin.rest.service.QueryService$$FastClassByCGLIB$$4957273f.invoke(<generated>) at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:618) at org.apache.kylin.rest.service.QueryService$$EnhancerByCGLIB$$e4e1e494.query(<generated>) at org.apache.kylin.rest.controller.QueryController.doQueryWithCache(QueryController.java:178) at org.apache.kylin.rest.controller.QueryController.query(QueryController.java:85) 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:606) at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:213) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789) at javax.servlet.http.HttpServlet.service(HttpServlet.java:646) at javax.servlet.http.HttpServlet.service(HttpServlet.java:727) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:201) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.ui.DefaultLoginPageGeneratingFilter.doFilter(DefaultLoginPageGeneratingFilter.java:91) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:183) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192) at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160) at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346) at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.kylin.rest.filter.KylinApiFilter.doFilterInternal(KylinApiFilter.java:66) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at com.thetransactioncompany.cors.CORSFilter.doFilter(CORSFilter.java:195) at com.thetransactioncompany.cors.CORSFilter.doFilter(CORSFilter.java:266) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1074) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:745) Caused by: org.apache.kylin.common.persistence.StorageException: Error when scan from lower key @ to upper key @��� on table KYLIN_FOBSAT4IR6. at org.apache.kylin.storage.hbase.CubeSegmentTupleIterator.doScan(CubeSegmentTupleIterator.java:221) at org.apache.kylin.storage.hbase.CubeSegmentTupleIterator.scanNextRange(CubeSegmentTupleIterator.java:202) at org.apache.kylin.storage.hbase.CubeSegmentTupleIterator.<init>(CubeSegmentTupleIterator.java:113) at org.apache.kylin.storage.hbase.SerializedHBaseTupleIterator.<init>(SerializedHBaseTupleIterator.java:64) at org.apache.kylin.storage.hbase.CubeStorageEngine.search(CubeStorageEngine.java:143) at org.apache.kylin.query.enumerator.CubeEnumerator.queryStorage(CubeEnumerator.java:149) at org.apache.kylin.query.enumerator.CubeEnumerator.moveNext(CubeEnumerator.java:74) at Baz$1$1.moveNext(Unknown Source) at org.apache.calcite.linq4j.EnumerableDefaults.groupBy_(EnumerableDefaults.java:737) at org.apache.calcite.linq4j.EnumerableDefaults.groupBy(EnumerableDefaults.java:677) at org.apache.calcite.linq4j.DefaultEnumerable.groupBy(DefaultEnumerable.java:301) at Baz.bind(Unknown Source) at org.apache.calcite.jdbc.CalcitePrepare$CalciteSignature.enumerable(CalcitePrepare.java:281) at org.apache.calcite.jdbc.CalciteConnectionImpl.enumerable(CalciteConnectionImpl.java:235) at org.apache.calcite.jdbc.CalciteMetaImpl.createIterable(CalciteMetaImpl.java:533) at org.apache.calcite.avatica.AvaticaResultSet.execute(AvaticaResultSet.java:184) at org.apache.calcite.jdbc.CalciteResultSet.execute(CalciteResultSet.java:63) at org.apache.calcite.jdbc.CalciteResultSet.execute(CalciteResultSet.java:42) at org.apache.calcite.avatica.AvaticaConnection$1.execute(AvaticaConnection.java:473) at org.apache.calcite.jdbc.CalciteMetaImpl.prepareAndExecute(CalciteMetaImpl.java:566) at org.apache.calcite.avatica.AvaticaConnection.prepareAndExecuteInternal(AvaticaConnection.java:477) at org.apache.calcite.avatica.AvaticaStatement.executeInternal(AvaticaStatement.java:109) ... 84 more Caused by: java.lang.NoSuchMethodError: org.apache.hadoop.hbase.client.Scan.setCaching(I)V at org.apache.kylin.storage.hbase.CubeSegmentTupleIterator.tuneScanParameters(CubeSegmentTupleIterator.java:270) at org.apache.kylin.storage.hbase.CubeSegmentTupleIterator.buildScan(CubeSegmentTupleIterator.java:254) at org.apache.kylin.storage.hbase.CubeSegmentTupleIterator.doScan(CubeSegmentTupleIterator.java:212) ... 105 more [http-bio-7070-exec-3]:[2016-01-23 12:51:44,718][INFO][org.apache.kylin.rest.service.QueryService.logQuery(QueryService.java:242)] - ==========================[QUERY]=============================== SQL: select part_dt, sum(price) as total_selled, count(distinct seller_id) as sellers from kylin_sales group by part_dt order by part_dt; User: ADMIN Success: false Duration: 0.0 Project: learn_kylin Realization Names: [kylin_sales_cube] Cuboid Ids: [64] Total scan count: 0 Result row count: 0 Accept Partial: true Is Partial Result: false Hit Cache: false Message: Error when scan from lower key @ to upper key @��� on table KYLIN_FOBSAT4IR6. while executing SQL: "select part_dt, sum(price) as total_selled, count(distinct seller_id) as sellers from kylin_sales group by part_dt order by part_dt LIMIT 10" ==========================[QUERY]===============================

kylin_query.log
Description: Binary data

在 2016年1月23日，上午3:02，Zhang, Edward (GDI Hadoop) <yonzh...@ebay.com> 写道： Can you please provide chained exceptions after the following stack trace where it will tell the root cause? You can cross check if your HBase is working well by running hbase shell and scan the table KYLIN_FOBSAT4IR6 thanks Edward From: Gqchen <chengq_1...@163.com> Reply-To: "user@kylin.apache.org" <user@kylin.apache.org> Date: Friday, January 22, 2016 at 5:25 To: "user@kylin.apache.org" <user@kylin.apache.org> Subject: kylin org sample query failed as "Error when scan from lower key @ to upper key" after build successfully  HI: I have depolyed kylin and build a cube with sample cube . I can build the cube and and run the jobs successfully as show in the following picture: PastedGraphic-1.tiff     But something bad happened when I Execute SQLs in the “Query” tab              "select part_dt, sum(price) as total_selled, count(distinct seller_id) as sellers from kylin_sales group by part_dt order by part_dt” Error when scan from lower key @ to upper key @��� on table KYLIN_FOBSAT4IR6. while executing SQL: "select part_dt, sum(price) as total_selled, count(distinct seller_id) as sellers from kylin_sales group by part_dt order by part_dt LIMIT 50000” returned      I get some logs from kylin_job.log : [http-bio-7070-exec-4]:[2016-01-22 21:12:15,663][ERROR][org.apache.kylin.rest.controller.BasicController.handleError(BasicController.java:46)] - org.apache.kylin.rest.exception.InternalErrorException: Error when scan from lower key @ to upper key @��� on table KYLIN_FOBSAT4IR6. while executing SQL: "select part_dt, sum(price) as total_selled, count(distinct seller_id) as sellers from kylin_sales group by part_dt order by part_dt LIMIT 10" at org.apache.kylin.rest.controller.QueryController.doQueryWithCache(QueryController.java:205) at org.apache.kylin.rest.controller.QueryController.query(QueryController.java:85) 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:606) at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:213) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789) at javax.servlet.http.HttpServlet.service(HttpServlet.java:646) at javax.servlet.http.HttpServlet.service(HttpServlet.java:727) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.ui.DefaultLoginPageGeneratingFilter.doFilter(DefaultLoginPageGeneratingFilter.java:91) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:183) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192) at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160) at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346) at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.kylin.rest.filter.KylinApiFilter.doFilterInternal(KylinApiFilter.java:66) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at com.thetransactioncompany.cors.CORSFilter.doFilter(CORSFilter.java:195) at com.thetransactioncompany.cors.CORSFilter.doFilter(CORSFilter.java:266) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1074) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:745) Can anyone give me some tips? Thank you !