ES won't run under Java 8 after ReadonlyREST upgrade

1

Is it possible to get a ReadonlyREST plugin compiled for Java 8 as used to be the case and very much still implied by the contents of …/elasticsearch/plugins/readonlyrest/plugin-descriptor.properties:

#
# This file is part of ReadonlyREST.
#
#     ReadonlyREST is free software: you can redistribute it and/or modify
#     it under the terms of the GNU General Public License as published by
#     the Free Software Foundation, either version 3 of the License, or
#     (at your option) any later version.
#
#     ReadonlyREST is distributed in the hope that it will be useful,
#     but WITHOUT ANY WARRANTY; without even the implied warranty of
#     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#     GNU General Public License for more details.
#
#     You should have received a copy of the GNU General Public License
#     along with ReadonlyREST.  If not, see http://www.gnu.org/licenses/
#
#
# Elasticsearch plugin descriptor file
# This file must exist as 'plugin-descriptor.properties' in a folder named `elasticsearch`
# inside all plugins.
#
name=readonlyrest
version=1.71.0
description=Safely expose Elasticsearch REST API
classname=tech.beshu.ror.es.ReadonlyRestPlugin
java.version=1.8
elasticsearch.version=6.8.23
2

Hi @mfoldbjerg

You are correct: since 1.62.0, ReadonlyREST needs Java 11 or newer, also for ES 6.8.x. The java.version=1.8 line in the plugin descriptor is our mistake, and we
will fix it. We do not plan Java 8 builds again.

Solution: run ES 6.8.23 on Java 11, which Elastic supports. Set JAVA_HOME to Java 11, run the ROR patch with it, then start ES.

ROR 1.61.1 is the last Java 8 version. It does not have the later security fixes, so we do not recommend it.