Require JRuby 1.7.

README.md

@@ -31,6 +31,14 @@ If you like, you can also use the documentation locally via
   gem install yard
   yard server
 
+## JRuby 1.7 Required
+
+As of Pacer 1.0.0, [JRuby](http://jruby.org/) 1.7 is required because it is both faster and
+fixes some problems that I previously had to work around in Pacer.
+
+The easiest way (ie. the way I do it) to get the most recent version of
+JRuby is to use [RVM](https://rvm.io/)
+
 ## Installation
 
 The easiest way to get Pacer is `gem install pacer`.

lib/pacer.rb

@@ -1,11 +1,11 @@
-if not defined?(JRUBY_VERSION) or JRUBY_VERSION =~ /^(0|1\.[0-5]|1\.6\.[0-3])/
+if not defined?(JRUBY_VERSION) or JRUBY_VERSION =~ /^(0|1\.[0-6])/
   # NOTE: This is because JRuby 1.6.4 fixes a bug that made it impossible to
   # instantiate Java classes with a varargs constructor signature  with 0
   # arguments. Marko would not accept a patch to create a 0 args constructor to
   # work around the problem, therefore this version of Pacer will not work
   # under any older versions of JRuby. The oldest Pacer version that will work
   # is 0.8.1.
-  raise Exception, 'Pacer >= 0.8.2 requires JRuby version 1.6.4 or higher. It is strongly recommended that you use the latest JRuby release.'
+  raise Exception, 'Pacer >= 1.0.0 requires JRuby version 1.7.0 preview or higher. It is strongly recommended that you use the latest JRuby release.'
 end
 
 if RUBY_VERSION == '1.8.7'
@@ -15,6 +15,7 @@
   defaulting to 1.9 mode by setting the environment variable
   JRUBY_OPTS=--1.9
 WARNING
+  raise Exception, "Pacer must be run in JRuby 1.9 mode"
 end
 
 require 'java'