[Bug]: Intermittent ArrayIndexOutOfBoundsException when recording position undo in Hop GUI

[leehaut]

Apache Hop version?

2.19.0

Java version?

jdk21

Operating system

Windows

What happened?

Description

When using Hop GUI, an intermittent java.lang.ArrayIndexOutOfBoundsException: Index 0 out of bounds for length 0 can appear in the event loop (sometimes noticed while closing the UI).

Stack trace example:

2026/08/02 10:37:33 - Hop - Projects enabled
2026/08/02 10:37:33 - Hop - Enabling project : 'hop_demo'
2026/08/02 10:37:33 - Hop - Two-way password encoder initialized with plugin ID 'Hop' for project 'hop_demo'
Error in the Hop GUI : Index 0 out of bounds for length 0
java.lang.ArrayIndexOutOfBoundsException: Index 0 out of bounds for length 0
        at org.apache.hop.core.undo.ChangeAction.setPosition(ChangeAction.java:213)
        at org.apache.hop.base.AbstractMeta.addUndo(AbstractMeta.java:500)
        at org.apache.hop.ui.hopgui.delegates.HopGuiUndoDelegate.addUndoPosition(HopGuiUndoDelegate.java:65)
        at org.apache.hop.ui.hopgui.file.pipeline.HopGuiPipelineGraph.mouseUp(HopGuiPipelineGraph.java:1254)
        at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:262)
        at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:91)
        at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4364)
        at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1217)
        at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4162)
        at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3750)
        at org.apache.hop.ui.hopgui.HopGui.open(HopGui.java:619)
        at org.apache.hop.ui.hopgui.HopGui.main(HopGui.java:453)

Issue Priority

Priority: 3

Issue Component

Component: Hop Gui

[leehaut]

.take-issue