Inserting twice in the same Lesson causes problems

[Michael Kargl]

When inserting in a Lesson... deleting some vocabs ... then insert new vocabs into the same Lesson again.. some of the studycards throw NullpointerExceptions.

Exception caught after invoking slot
java.lang.NullPointerException
 at src.modules.studycard.QStudycardModule.showStudycardDetails(QStudycardModule.java:119)
 at src.modules.studycard.QStudycardModule.on_btnShow_clicked(QStudycardModule.java:344)
 at sun.reflect.GeneratedMethodAccessor57.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:616)
 at com.trolltech.qt.internal.QSignalEmitterInternal$AbstractSignalInternal.emit_helper(QSignalEmitterInternal.java:368)
 at com.trolltech.qt.QSignalEmitter$Signal1.emit(QSignalEmitter.java:209)
 at com.trolltech.qt.gui.QApplication.exec(Native Method)
 at src.main.Main.main(Main.java:61)
Hibernate: select lessonenti0_.lnr as lnr5_, lessonenti0_.name as name5_ from Lesson lessonenti0_