ArrayIndexOutOfBoundsException on ClassConfigurator.get() --------------------------------------------------------- Key: JGRP-2088 URL: https://issues.jboss.org/browse/JGRP-2088 Project: JGroups Issue Type: Bug Affects Versions: 3.6.10 Reporter: Manuel Dominguez Sarmiento Assignee: Bela Ban Fix For: 3.6.11, 4.0 Attachments: jgroups.xml See the following stack trace: [ERROR] 2016-07-09 14:26:05 [UDP-multicast receiver,shared=jgroups-shared-transport] - JGRP000030: null: failed handling incoming message: java.lang.ArrayIndexOutOfBoundsException: -1 java.lang.ArrayIndexOutOfBoundsException: -1 at org.jgroups.conf.ClassConfigurator.get(ClassConfigurator.java:161) at org.jgroups.Message.readHeader(Message.java:936) at org.jgroups.Message.readFrom(Message.java:811) at org.jgroups.protocols.TP.handleSingleMessage(TP.java:1712) at org.jgroups.protocols.TP.receive(TP.java:1654) at org.jgroups.protocols.UDP$PacketReceiver.run(UDP.java:701) at java.lang.Thread.run(Thread.java:745) Stepping through the code with the debugger shows that the following line is failing at ClassConfigurator.get() with magic = -1 thus the java.lang.ArrayIndexOutOfBoundsException return magic < 1024 ? magicMap[magic] : (Class)magicMapUser.get(Short.valueOf(magic)); See attached jgroups.xml for configuration. This showed up when upgrading to 3.6.10 from 3.6.8 which worked fine.