Extract magic char as a constant.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1594019 13f79535-47bb-0310-9956-ffa450edef68
Rename ivar proxyCause to causeProxy. Working toward new XML and JSON Serialization and Deserialization.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1594020 13f79535-47bb-0310-9956-ffa450edef68
Rename getCause() to getCauseProxy(). The goal is to make a clear distinction between an exception object that is a proxy vs. not. Working toward new XML and JSON Serialization and Deserialization.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1594022 13f79535-47bb-0310-9956-ffa450edef68
Add ivars to track the throwable's message and localized message since the real Throwable class may not exist in the JVM (or ClassLoader) where the proxy is derserialized. Working toward new XML and JSON Serialization and Deserialization.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1594027 13f79535-47bb-0310-9956-ffa450edef68