Improve performance of Message#writeHeader ------------------------------------------ Key: JGRP-2042 URL: https://issues.jboss.org/browse/JGRP-2042 Project: JGroups Issue Type: Enhancement Reporter: Sanne Grinovero Assignee: Bela Ban Priority: Minor Fix For: 4.0 The following stacktrace, taken with JFR, is highlighting a CPU consumer which could be optimised. {noformat}Stack Trace Sample Count Percentage(%) java.util.IdentityHashMap.get(Object) 66 2.224 org.jgroups.conf.ClassConfigurator.getMagicNumber(Class) 66 2.224 org.jgroups.Message.writeHeader(Header, DataOutput) 66 2.224 {noformat} One idea could be to use an ad-hoc implementation of Map which takes advantage of the key being a {{Class}}. An interesting alternative would be to avoid the map lookup altogether, by having the Header expose a method like "writeMagicNumber(DataInput to)".