这里空指针异常是哪里错了？

private void saveaction_performed(ActionEvent e){
DBConnection con=new DBConnection();
Traint traint=new Traint();
traint.setNo(No_jf.getText());
traint.setKindname(Kindname_jf.getText());
traint.setKind(Kind_cob.getSelectedItem().toString());
traint.setMonth(Month_cob.getSelectedItem().toString());
traint.setDepartment(Department_jf.getText());
traint.setSponsor(Sponsor_jf.getText());
traint.setTraincompany(TrainCompany_jf.getText());
traint.setTeacher(teacher_jf.getText());
traint.setTeachmethods(Teachingmethods_cob.getSelectedItem().toString());
traint.setClasshours(ClassHours_jf.getText());
traint.setPay(Pay_jf.getText());
traint.setStartdate(ClassStartDate_jf.getText());
traint.setOverdate(ClassOverDate_jf.getText());
traint.setPlace(Place_jf.getText());
traint.setContent(Content_jf.getText());
traint.setExamkind(ExamKind_jf.getText());
traint.setBooks(Books_jf.getText());
traint.setRemarks(Remarks_jf.getText());
con.insertintoTraint(traint);
                                   ｝
报错    Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at com.mwq.frame.TrainManagement.saveaction_performed(TrainManagement.java:293)
at com.mwq.frame.TrainManagement.access$0(TrainManagement.java:289)
at com.mwq.frame.TrainManagement$1.actionPerformed(TrainManagement.java:64)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) --------------------编程问答-------------------- 这样贴很难看的出的。 --------------------编程问答-------------------- 根据错误提示，你这是没连上数据源，con.insertintoTraint(traint);我估计应该是这个里面出问题了。

TrainManagement.java:293
这个提示，我真的不知道是哪行代码。

补充：Java ,  Eclipse