While using the ElasticSearch index provider, I noticed that the uploading of some JSON documents into ElasticSearch failed, due to an invalid JSON error.

The issue comes down to the fact the CompactJsonWriter incorrectly escape single-quote characters: https://github.com/ModeShape/modeshape/blob/master/modeshape-schematic/src/main/java/org/modeshape/schematic/internal/document/CompactJsonWriter.java#L174

See the JSON grammar describing which characters can be escaped: http://www.json.org/string.gif
The single-quote character is not on this list.