when i used the REST API: http://domain:port/api/1.0/reservationgroups/gid/ to request reservation license hardwareid, will occur follow exception, the exception means the H2 database connection has been closed, maybe the timeout is not enough long for deal with the hardwareid saved to database? javax.servlet.ServletException: org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.transaction.TransactionSystemException: Could not commit JPA transaction; nested exception is javax.persistence.RollbackException: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.7.1.v20171221-bd47e8f): org.eclipse.persistence.exceptions.DatabaseException Internal Exception: java.sql.SQLException: Connection has already been closed. Error Code: 0 at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146) at org.eclipse.jetty.server.handler.StatisticsHandler.handle(StatisticsHandler.java:169) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.Server.handle(Server.java:564) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:317) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:279) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:110) at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:124) at org.eclipse.jetty.util.thread.Invocable.invokePreferred(Invocable.java:128) at org.eclipse.jetty.util.thread.Invocable$InvocableExecutor.invoke(Invocable.java:222) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:294) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:199) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:673) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:591) at java.lang.Thread.run(Thread.java:745) ... View more