[jgroups-users] ArrayIndexOutOfBounds exception in STABLE.installView()

Hi,

In Apache Geode I have a small protocol stack with no GMS where I manage 
and install my own membership view into the channel. During one 
transition I need to clear the view from the stack so I create a View 
with no members and send it in a view-change to the channel.  
Unfortunately STABLE isn't using View.getCoord() to get the current 
membership coordinator and is using getMembers().get(0) instead, causing 
an exception.

         ViewId vid = new ViewId(new JGAddress(), 0);
         List<Address> members = new ArrayList<>();
         View jgv = new View(vid, members);
         this.myChannel.down(new Event(Event.VIEW_CHANGE, jgv));

java.lang.ArrayIndexOutOfBoundsException: 0
at java.util.Arrays$ArrayList.get(Arrays.java:3841)
at java.util.Collections$UnmodifiableList.get(Collections.java:1309)
at org.jgroups.protocols.pbcast.STABLE.handleViewChange(STABLE.java:365)
at org.jgroups.protocols.pbcast.STABLE.down(STABLE.java:328)
at org.jgroups.protocols.FlowControl.down(FlowControl.java:347)
at org.jgroups.protocols.FlowControl.down(FlowControl.java:347)
at org.jgroups.protocols.FRAG2.down(FRAG2.java:136)
at org.jgroups.stack.ProtocolStack.down(ProtocolStack.java:1039)
at org.jgroups.JChannel.down(JChannel.java:790)
at 
org.apache.geode.distributed.internal.membership.gms.messenger.JGroupsMessenger.start(JGroupsMessenger.java:310)

It seems like any use of View.getMembers().get(0) should be changed to 
View.getCoord() and the code should be prepared to deal with a null 
return value.

Bruce Schuchardt


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