Ich entwickle eine Anwendung für eine Firma, , die eine Oracle-Datenbank auf verschiedene Arten verwaltet. Das Programm ist in Java, NetBeans und es wird ziemlich groß. Ich würde nicht sagen, es ist sehr gut geschrieben, aber ich oft zurück zu älteren schlechten Code und versuchen, es als lesbar und oop machen, wie ich kann.Java - NullPointerException beim Start. Swing Bug oder fehlerhafte Implementierung?
Ich habe bemerkt, dass 1 von 10 Mal, als ich das Programm zu starten, ich die folgende Ausnahme erhalten: (obwohl das Programm gestartet und richtig, auch diese Zeiten funktioniert)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at javax.swing.plaf.synth.SynthLabelUI.getMinimumSize(SynthLabelUI.java:199)
at javax.swing.JComponent.getMinimumSize(JComponent.java:1702)
at javax.swing.GroupLayout$ComponentSpring.calculateNonlinkedMinimumSize(GroupLayout.java:2933)
at javax.swing.GroupLayout$ComponentSpring.calculateMinimumSize(GroupLayout.java:2897)
at javax.swing.GroupLayout$Spring.getMinimumSize(GroupLayout.java:1315)
at javax.swing.GroupLayout$ComponentSpring.calculatePreferredSize(GroupLayout.java:2904)
at javax.swing.GroupLayout$Spring.getPreferredSize(GroupLayout.java:1325)
at javax.swing.GroupLayout$Group.getSpringSize(GroupLayout.java:1604)
at javax.swing.GroupLayout$Group.calculateSize(GroupLayout.java:1593)
at javax.swing.GroupLayout$Group.calculatePreferredSize(GroupLayout.java:1568)
at javax.swing.GroupLayout$Spring.getPreferredSize(GroupLayout.java:1325)
at javax.swing.GroupLayout$Group.getSpringSize(GroupLayout.java:1604)
at javax.swing.GroupLayout$Group.calculateSize(GroupLayout.java:1590)
at javax.swing.GroupLayout$Group.calculatePreferredSize(GroupLayout.java:1568)
at javax.swing.GroupLayout$Spring.getPreferredSize(GroupLayout.java:1325)
at javax.swing.GroupLayout$Group.getSpringSize(GroupLayout.java:1604)
at javax.swing.GroupLayout$Group.calculateSize(GroupLayout.java:1593)
at javax.swing.GroupLayout$Group.calculatePreferredSize(GroupLayout.java:1568)
at javax.swing.GroupLayout$Spring.getPreferredSize(GroupLayout.java:1325)
at javax.swing.GroupLayout$Group.getSpringSize(GroupLayout.java:1604)
at javax.swing.GroupLayout$Group.calculateSize(GroupLayout.java:1590)
at javax.swing.GroupLayout$Group.calculatePreferredSize(GroupLayout.java:1568)
at javax.swing.GroupLayout$Spring.getPreferredSize(GroupLayout.java:1325)
at javax.swing.GroupLayout$Group.getSpringSize(GroupLayout.java:1604)
at javax.swing.GroupLayout$Group.calculateSize(GroupLayout.java:1590)
at javax.swing.GroupLayout$Group.calculatePreferredSize(GroupLayout.java:1568)
at javax.swing.GroupLayout$Spring.getPreferredSize(GroupLayout.java:1325)
at javax.swing.GroupLayout$Group.getSpringSize(GroupLayout.java:1604)
at javax.swing.GroupLayout$Group.calculateSize(GroupLayout.java:1588)
at javax.swing.GroupLayout$Group.calculatePreferredSize(GroupLayout.java:1568)
at javax.swing.GroupLayout$Spring.getPreferredSize(GroupLayout.java:1325)
at javax.swing.GroupLayout.calculateAutopadding(GroupLayout.java:1050)
at javax.swing.GroupLayout.prepare(GroupLayout.java:1037)
at javax.swing.GroupLayout.preferredLayoutSize(GroupLayout.java:857)
at java.awt.Container.preferredSize(Container.java:1599)
at java.awt.Container.getPreferredSize(Container.java:1584)
at javax.swing.JComponent.getPreferredSize(JComponent.java:1624)
at javax.swing.GroupLayout$ComponentSpring.calculateNonlinkedPreferredSize(GroupLayout.java:2944)
at javax.swing.GroupLayout$ComponentSpring.calculateNonlinkedMinimumSize(GroupLayout.java:2930)
at javax.swing.GroupLayout$ComponentSpring.calculateMinimumSize(GroupLayout.java:2897)
at javax.swing.GroupLayout$Spring.getMinimumSize(GroupLayout.java:1315)
at javax.swing.GroupLayout$ComponentSpring.calculatePreferredSize(GroupLayout.java:2904)
at javax.swing.GroupLayout$Spring.getPreferredSize(GroupLayout.java:1325)
at javax.swing.GroupLayout$Group.getSpringSize(GroupLayout.java:1604)
at javax.swing.GroupLayout$Group.calculateSize(GroupLayout.java:1593)
at javax.swing.GroupLayout$Group.calculatePreferredSize(GroupLayout.java:1568)
at javax.swing.GroupLayout$Spring.getPreferredSize(GroupLayout.java:1325)
at javax.swing.GroupLayout$Group.getSpringSize(GroupLayout.java:1604)
at javax.swing.GroupLayout$Group.calculateSize(GroupLayout.java:1588)
at javax.swing.GroupLayout$Group.calculatePreferredSize(GroupLayout.java:1568)
at javax.swing.GroupLayout$Spring.getPreferredSize(GroupLayout.java:1325)
at javax.swing.GroupLayout$Group.getSpringSize(GroupLayout.java:1604)
at javax.swing.GroupLayout$Group.calculateSize(GroupLayout.java:1588)
at javax.swing.GroupLayout$Group.calculatePreferredSize(GroupLayout.java:1568)
at javax.swing.GroupLayout$Spring.getPreferredSize(GroupLayout.java:1325)
at javax.swing.GroupLayout$SequentialGroup.setValidSize(GroupLayout.java:1972)
at javax.swing.GroupLayout$Group.setSize(GroupLayout.java:1553)
at javax.swing.GroupLayout.calculateAutopadding(GroupLayout.java:1058)
at javax.swing.GroupLayout.layoutContainer(GroupLayout.java:897)
at java.awt.Container.layout(Container.java:1421)
at java.awt.Container.doLayout(Container.java:1410)
at java.awt.Container.validateTree(Container.java:1507)
at java.awt.Container.validateTree(Container.java:1513)
at java.awt.Container.validateTree(Container.java:1513)
at java.awt.Container.validateTree(Container.java:1513)
at java.awt.Container.validateTree(Container.java:1513)
at java.awt.Container.validateTree(Container.java:1513)
at java.awt.Container.validate(Container.java:1480)
at java.awt.Window.dispatchEventImpl(Window.java:2473)
at java.awt.Component.dispatchEvent(Component.java:4460)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Ich nehme an, es ist ein Swing Bug. Könnte es ein Problem bei meiner Implementierung sein? Warum passiert es 1 von 10 Mal und nicht immer? Kann ich etwas tun, um es zu vermeiden?
Sie starten Sie die GUI auf dem EDT? – willcodejavaforfood
@willcodejavaforfood: Guter Punkt. Ich bin der Meinung, dass Swing Ausnahmen auslösen sollte, wenn GUI-Operationen außerhalb des Event Dispatch Threads (wie SWT) ausgeführt werden. Indem sie keine Ausnahmen machen, setzen sie sich für Verstöße gegen das Prinzip des geringsten Erstaunens ein. :) –
@Adam Paynter IMO Swing sollte nicht fadenfeindlich sein. Aber es ist und es kann nicht viel getan werden. –