We had several problems with Java Serializatin in the past. At some point
in the Java 1.7.x series JDKs where not compatible anymore when java
serialization (ObjectStream) was used to exchange objects. In elasticsearch
we used this to serialize exceptions across the wire which caused several problems
with incompatible JDKs. While causing lot of trouble this essentially prevented
users from moving forward and upgrade their JVMs. To prevent these kind of issues
this commit removes the dependency on java serialization entirely and bans the
usage of ObjectOutputStream and ObjectInputStream entirely.
Yet, we can't fully serialize all exception anymore such that this commit
is best effort and adds hand written serialization to all elasticsearch exceptions
as well to a selected set of JDK and Lucene exceptions. (see StreamOutput#writeThrowable /
StreamInput.readThrowable). Stacktraces should be preserved for all exceptions while
several names might be replaced with ElasticsearchException if there is no mapping for
the given exception.
Added a licenses/ directory to core which contains a sha1 file for each JAR
dependency, and one or more LICENSE files and one NOTICE file for each
project.
Also adds dev-tools/src/main/resources/license-check/check_license_and_sha.pl
which checks that the licenses/ dir is up to date during a mvn verify,
and which can be used to update the sha1 files when upgrading dependencies.
Closes#2794Closes#10684Closes#11705
Robert Muir
Simon Willnauer
Clinton Gormley
Ryan Ernst