Description Kyle Girard 2020-02-16 20:03:32 EST

I upgraded our RCP to Java 11 and Eclipse 2019-12 from Java 8 and Eclipse Oxygen.  Surprisingly every seems to work.  However, When I add nodes to my graph in a certain order I get a index out of bounds exception (on both linux and windows) in ContentBehavior: (here's the relevant parts):

java.lang.IndexOutOfBoundsException: Index: 16, Size: 11
	at java.base/java.util.ArrayList.rangeCheckForAdd(ArrayList.java:787)
	at java.base/java.util.ArrayList.addAll(ArrayList.java:731)
	at com.google.common.collect.ForwardingList.addAll(ForwardingList.java:75)
	at org.eclipse.gef.common.collections.ObservableListWrapperEx.addAll(ObservableListWrapperEx.java:122)
	at org.eclipse.gef.mvc.fx.parts.AbstractVisualPart.addChildren(AbstractVisualPart.java:200)
	at org.eclipse.gef.mvc.fx.behaviors.ContentBehavior.lambda$1(ContentBehavior.java:501)
	at com.google.common.collect.Maps$KeySet.lambda$forEach$0(Maps.java:3822)
	at java.base/java.util.HashMap.forEach(HashMap.java:1336)
	at com.google.common.collect.Maps$KeySet.forEach(Maps.java:3822)
	at org.eclipse.gef.mvc.fx.behaviors.ContentBehavior.synchronizeContentPartChildren(ContentBehavior.java:498)
	at org.eclipse.gef.mvc.fx.behaviors.ContentBehavior$2.onChanged(ContentBehavior.java:123)
	at org.eclipse.gef.common.collections.ListListenerHelperEx.notifyListChangeListeners(ListListenerHelperEx.java:650)
	at org.eclipse.gef.common.beans.binding.ListExpressionHelperEx.fireValueChangedEvent(ListExpressionHelperEx.java:109)
	at org.eclipse.gef.common.beans.property.ReadOnlyListWrapperEx$ReadOnlyPropertyImpl.fireValueChangedEvent(ReadOnlyListWrapperEx.java:91)
	at org.eclipse.gef.common.beans.property.ReadOnlyListWrapperEx$ReadOnlyPropertyImpl.access$2(ReadOnlyListWrapperEx.java:87)
	at org.eclipse.gef.common.beans.property.ReadOnlyListWrapperEx.fireValueChangedEvent(ReadOnlyListWrapperEx.java:234)
	at javafx.base/javafx.beans.property.ListPropertyBase.lambda$new$0(ListPropertyBase.java:57)
	at javafx.base/com.sun.javafx.collections.ListListenerHelper$SingleChange.fireValueChangedEvent(ListListenerHelper.java:164)
	at javafx.base/com.sun.javafx.collections.ListListenerHelper.fireValueChangedEvent(ListListenerHelper.java:73)
	at javafx.base/javafx.collections.ObservableListBase.fireChange(ObservableListBase.java:233)
	at javafx.base/javafx.collections.FXCollections$UnmodifiableObservableListImpl.lambda$new$0(FXCollections.java:955)
	at javafx.base/javafx.collections.WeakListChangeListener.onChanged(WeakListChangeListener.java:88)
	at org.eclipse.gef.common.collections.ListListenerHelperEx.notifyListChangeListeners(ListListenerHelperEx.java:650)
	at org.eclipse.gef.common.collections.ListListenerHelperEx.fireValueChangedEvent(ListListenerHelperEx.java:600)
	at org.eclipse.gef.common.collections.ObservableListWrapperEx.setAll(ObservableListWrapperEx.java:355)
	at org.eclipse.gef.mvc.fx.parts.AbstractContentPart.addContentChild(AbstractContentPart.java:132)
	at org.eclipse.gef.mvc.fx.operations.AddContentChildOperation.execute(AddContentChildOperation.java:78)
	at org.eclipse.gef.mvc.fx.operations.AbstractCompositeOperation.execute(AbstractCompositeOperation.java:142)
	at org.eclipse.gef.mvc.fx.policies.AbstractPolicy.locallyExecuteOperation(AbstractPolicy.java:143)
	at org.eclipse.gef.mvc.fx.policies.ContentPolicy.addContentChild(ContentPolicy.java:71)
	at org.eclipse.gef.mvc.fx.policies.CreationPolicy.create(CreationPolicy.java:118)
	at org.eclipse.gef.mvc.fx.policies.CreationPolicy.create(CreationPolicy.java:200)


I investigated and it appears that since childContentsParts.keySet() can return integers in any order.  If it returns the index of next element added everything works.  If it returns anything else the above exception is thrown.  To test this...I created my own copy ContentBehavior class where I convert the keySet to an array and sort it and leave everything else unchanged and I don't get the exception anymore.  

Replace:

childContentParts.keySet().foreach(cp -> { ....

with 

ArrayList<Integer> keys = new ArrayList<>(childContentParts.keySet());
Collections.sort(keys);
keys.forEach(cp -> { .....


Don't have time to investigate it further to see if this is a proper fix but it works for me.