This error is how to return a responsibility excuse me?-CodePudding

Java. IO. EOFException
The at Java. IO. ObjectInputStream $BlockDataInputStream. PeekByte (ObjectInputStream. Java: 2960)
The at Java. IO. ObjectInputStream. ReadObject0 (ObjectInputStream. Java: 1540)
The at Java. IO. ObjectInputStream. ReadObject (ObjectInputStream. Java: 431)
At the client. The Action. DoAction (49) Action. Java:
The at GUI. ExamMainFrame. SubmitPaper (ExamMainFrame. Java: 324)
The at GUI. ExamMainFrame. ActionPerformed (ExamMainFrame. Java: 227)
The at javax.mail. Swing. AbstractButton. FireActionPerformed (AbstractButton. Java: 2022)
The at javax.mail. Swing. AbstractButton $Handler. The actionPerformed (AbstractButton. Java: 2348)
The at javax.mail. Swing. DefaultButtonModel. FireActionPerformed (DefaultButtonModel. Java: 402)
The at javax.mail. Swing. DefaultButtonModel. SetPressed (DefaultButtonModel. Java: 259)
The at javax.mail. Swing. Plaf. Basic. BasicButtonListener. MouseReleased (BasicButtonListener. Java: 252)
At java.awt.Com ponent. ProcessMouseEvent (Component. Java: 6539)
The at javax.mail. Swing. Jcomponents. ProcessMouseEvent (jcomponents. Java: 3324)
At java.awt.Com ponent. The processEvent (Component. Java: 6304)
The at Java. The awt. Container. The processEvent (Container. Java: 2239)
At java.awt.Com ponent. DispatchEventImpl (Component. Java: 4889)
The at Java awt. Container. DispatchEventImpl (Container. Java: 2297)
At java.awt.Com ponent. DispatchEvent (Component. Java: 4711)
The at Java awt. LightweightDispatcher. RetargetMouseEvent (Container. Java: 4904)
The at Java awt. LightweightDispatcher. ProcessMouseEvent (Container. Java: 4535)
The at Java awt. LightweightDispatcher. DispatchEvent (Container. Java: 4476)
The at Java awt. Container. DispatchEventImpl (Container. Java: 2283)
The at Java awt. Window. DispatchEventImpl (2746) the Window. The Java:
At java.awt.Com ponent. DispatchEvent (Component. Java: 4711)
The at Java awt. EventQueue. DispatchEventImpl (EventQueue. Java: 760)
At Java awt. EventQueue. Access the $500 (97) EventQueue. Java:
At Java awt. EventQueue $3. The run (709) EventQueue. Java:
At Java awt. EventQueue $3. The run (703) EventQueue. Java:
The at Java. Security. The AccessController. DoPrivileged (Native Method)
The at Java. Security. ProtectionDomain $JavaSecurityAccessImpl. DoIntersectionPrivilege (ProtectionDomain. Java: 74)
The at Java. Security. ProtectionDomain $JavaSecurityAccessImpl. DoIntersectionPrivilege (ProtectionDomain. Java: 84)
The at Java awt. EventQueue $4. The run (EventQueue. Java: 733)
The at Java awt. EventQueue $4. The run (EventQueue. Java: 731)
The at Java. Security. The AccessController. DoPrivileged (Native Method)
The at Java. Security. ProtectionDomain $JavaSecurityAccessImpl. DoIntersectionPrivilege (ProtectionDomain. Java: 74)
The at Java awt. EventQueue. DispatchEvent (EventQueue. Java: 730)
The at Java awt. EventDispatchThread. PumpOneEventForFilters (EventDispatchThread. Java: 205)
The at Java awt. EventDispatchThread. PumpEventsForFilter (EventDispatchThread. Java: 116)
The at Java awt. EventDispatchThread. PumpEventsForHierarchy (EventDispatchThread. Java: 105)
The at Java awt. EventDispatchThread. PumpEvents (EventDispatchThread. Java: 101)
The at Java awt. EventDispatchThread. PumpEvents (EventDispatchThread. Java: 93)
The at Java awt. EventDispatchThread. Run (EventDispatchThread. Java: 82)
The Exception in the thread "is the AWT - EventQueue - 0" Java. Lang. NullPointerException
The at GUI. ExamMainFrame. SubmitPaper (ExamMainFrame. Java: 326)
The at GUI. ExamMainFrame. ActionPerformed (ExamMainFrame. Java: 227)
The at javax.mail. Swing. AbstractButton. FireActionPerformed (AbstractButton. Java: 2022)
The at javax.mail. Swing. AbstractButton $Handler. The actionPerformed (AbstractButton. Java: 2348)
The at javax.mail. Swing. DefaultButtonModel. FireActionPerformed (DefaultButtonModel. Java: 402)
The at javax.mail. Swing. DefaultButtonModel. SetPressed (DefaultButtonModel. Java: 259)
The at javax.mail. Swing. Plaf. Basic. BasicButtonListener. MouseReleased (BasicButtonListener. Java: 252)
At java.awt.Com ponent. ProcessMouseEvent (Component. Java: 6539)
The at javax.mail. Swing. Jcomponents. ProcessMouseEvent (jcomponents. Java: 3324)
At java.awt.Com ponent. The processEvent (Component. Java: 6304)
The at Java. The awt. Container. The processEvent (Container. Java: 2239)
At java.awt.Com ponent. DispatchEventImpl (Component. Java: 4889)
The at Java awt. Container. DispatchEventImpl (Container. Java: 2297)
At java.awt.Com ponent. DispatchEvent (Component. Java: 4711)
The at Java awt. LightweightDispatcher. RetargetMouseEvent (Container. Java: 4904)
The at Java awt. LightweightDispatcher. ProcessMouseEvent (Container. Java: 4535)
The at Java awt. LightweightDispatcher. DispatchEvent (Container. Java: 4476)
The at Java awt. Container. DispatchEventImpl (Container. Java: 2283)
The at Java awt. Window. DispatchEventImpl (2746) the Window. The Java:
At java.awt.Com ponent. DispatchEvent (Component. Java: 4711)
The at Java awt. EventQueue. DispatchEventImpl (EventQueue. Java: 760)
At Java awt. EventQueue. Access the $500 (97) EventQueue. Java:
At Java awt. EventQueue $3. The run (709) EventQueue. Java:
At Java awt. EventQueue $3. The run (703) EventQueue. Java:
The at Java. Security. The AccessController. DoPrivileged (Native Method)
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