Đây Là Phần Thông Báo Lỗi Của Mình
Exception in thread "AWT-EventQueue-0" java.lang.RuntimeException: com.microsoft.sqlserver.jdbc.SQLServerException: The connection is closed.
at com.edusys.DAO.KhoaHocDAO.selectBySql(KhoaHocDAO.java:78)
at com.edusys.DAO.KhoaHocDAO.selectAll(KhoaHocDAO.java:46)
at com.edusys.ui.ThongKeJDialog.fillComBoBoxKhoaHoc(ThongKeJDialog.java:359)
at com.edusys.ui.ThongKeJDialog.init(ThongKeJDialog.java:337)
at com.edusys.ui.ThongKeJDialog.<init>(ThongKeJDialog.java:28)
at com.edusys.ui.ThongKeJDialog$3.run(ThongKeJDialog.java:300)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
Caused by: com.microsoft.sqlserver.jdbc.SQLServerException: The connection is closed.
at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:171)
at com.microsoft.sqlserver.jdbc.SQLServerConnection.checkClosed(SQLServerConnection.java:319)
at com.microsoft.sqlserver.jdbc.SQLServerStatement.checkClosed(SQLServerStatement.java:956)
at com.microsoft.sqlserver.jdbc.SQLServerResultSet.checkClosed(SQLServerResultSet.java:348)
at com.microsoft.sqlserver.jdbc.SQLServerResultSet.getStatement(SQLServerResultSet.java:4263)
at com.edusys.DAO.KhoaHocDAO.selectBySql(KhoaHocDAO.java:75)
... 19 more
đây là đoạn báo lỗi của mình
mình đã mò rất nhiều và khá lâu mà k fix dc mong các bạn hỗ trợ ^^