Add some JRuby test workarounds, and README notification on feature.

Author: gkellogg

.travis.yml

@@ -7,12 +7,11 @@ rvm:
   - 1.9.3
   - 2.0
   - 2.1
-  - 2.2
+  - 2.2.1
   - jruby
 cache: bundler
 sudo: false
 matrix:
   allow_failures:
-    - rvm: 2.2
     - rbx-2
 

README.md

@@ -16,6 +16,9 @@ If the [jsonlint][] gem is installed, it will be used when validating an input d
 
 Install with `gem install json-ld`
 
+### MultiJson parser
+The [MultiJson](https://rubygems.org/gems/multi_json) gem is used for parsing JSON; this defaults to the native JSON parser, but will use a more performant parser if one is available. A specific parser can be specified by adding the `:adapter` option to any API call. See [MultiJson](https://rubygems.org/gems/multi_json) for more information.
+
 ### JSON-LD Streaming Profile
 This gem implements an optimized streaming writer used for generating JSON-LD from large repositories. Such documents result in the JSON-LD Streaming Profile:
 

json-ld.gemspec

@@ -30,8 +30,8 @@ Gem::Specification.new do |gem|
   gem.add_runtime_dependency     'rdf',             '~> 1.1', '>= 1.1.7'
   gem.add_runtime_dependency     'multi_json',      '~> 1.11'
   gem.add_development_dependency 'jsonlint',        '~> 0.1.0' unless RUBY_ENGINE == "jruby"
-  gem.add_development_dependency 'oj',              '~> 2.12'
-  gem.add_development_dependency 'yajl-ruby',       '~> 1.2.1'
+  gem.add_development_dependency 'oj',              '~> 2.12'  unless RUBY_ENGINE == "jruby"
+  gem.add_development_dependency 'yajl-ruby',       '~> 1.2.1' unless RUBY_ENGINE == "jruby"
   gem.add_development_dependency "rack-cache",      '~> 1.2'
   gem.add_development_dependency "rest-client",     '~> 1.8'
   gem.add_development_dependency "rest-client-components", '~> 1.4'

spec/api_spec.rb

@@ -76,7 +76,7 @@
           expanded = filename.sub(/-input\..*$/, '-expanded.json')
           ttl = filename.sub(/-input\..*$/, '-rdf.ttl')
 
-          context test do
+          context test, skip: ("Not supported in JRuby" if RUBY_ENGINE == "jruby" && %w(oj yajl).include?(adapter.to_s)) do
             it "expands" do
               options = {debug: @debug, adapter: adapter}
               options[:expandContext] = File.open(context) if context