diff --git a/README.md b/README.md
index 3dfaa9a..fd3692f 100644
--- a/README.md
+++ b/README.md
@@ -2,15 +2,32 @@
 
 [![Build Status](https://travis-ci.org/boxen/puppet-java.png?branch=master)](https://travis-ci.org/boxen/puppet-java)
 
-Installs Java 7u51 and unlimited key length security policy files..
+Installs Java 7 and unlimited key length security policy files..
 
 
 ## Usage
 
 ```puppet
+# Install the default version of both the JDK and JRE
 include java
 ```
 
+## Parameters
+
+You can customise this module by configuring some optional class parameters. Usually you'd do this via Hiera, but you could also explicitly pass those parameters in puppet code like `class { 'java': $update_version => '42', }`.
+
+* `update_version`: The 'update' part of the JRE/JDK version to install. For example, if you specify `51`, the module would install java 7u51
+* `base_download_url`: A base path from which the JRE and JDK packages should be downloaded. For example, if you specify `https://myorg.example/dist/java`, this module would download the jre from `https://myorg.example/dist/java/jre-7u51-macosx-x64.dmg`.
+
+All of these parameters have sensible defaults, and are provided if you need more control.
+
+Example hiera data in YAML:
+
+```yaml
+java::update_version: '51'
+java::base_download_url: 'https://myorg.example/dist/java'
+```
+
 ## Required Puppet Modules
 
 * `boxen`
diff --git a/manifests/init.pp b/manifests/init.pp
index 23604f4..e85d2d1 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -3,21 +3,25 @@
 # Examples
 #
 #    include java
-class java {
+class java (
+  $update_version = '51',
+  $base_download_url = 'https://s3.amazonaws.com/boxen-downloads/java'
+) {
   include boxen::config
 
-  $jre_url = 'https://s3.amazonaws.com/boxen-downloads/java/jre-7u51-macosx-x64.dmg'
-  $jdk_url = 'https://s3.amazonaws.com/boxen-downloads/java/jdk-7u51-macosx-x64.dmg'
+  $jre_url = "${base_download_url}/jre-7u${update_version}-macosx-x64.dmg"
+  $jdk_url = "${base_download_url}/jdk-7u${update_version}-macosx-x64.dmg"
   $wrapper = "${boxen::config::bindir}/java"
-  $sec_dir = '/Library/Java/JavaVirtualMachines/jdk1.7.0_21.jdk/Contents/Home/jre/lib/security'
+  $jdk_dir = "/Library/Java/JavaVirtualMachines/jdk1.7.0_${update_version}.jdk"
+  $sec_dir = "${jdk_dir}/Contents/Home/jre/lib/security"
 
   package {
-    'jre-7u51.dmg':
+    "jre-7u${update_version}.dmg":
       ensure   => present,
       alias    => 'java-jre',
       provider => pkgdmg,
       source   => $jre_url ;
-    'jdk-7u51.dmg':
+    "jdk-7u${update_version}.dmg":
       ensure   => present,
       alias    => 'java',
       provider => pkgdmg,
diff --git a/spec/classes/java_spec.rb b/spec/classes/java_spec.rb
index 86f4e76..454cb91 100644
--- a/spec/classes/java_spec.rb
+++ b/spec/classes/java_spec.rb
@@ -2,22 +2,28 @@
 
 describe "java" do
   let(:facts) { default_test_facts }
+  let(:params) {
+    {
+      :update_version => '42',
+      :base_download_url => 'https://downloads.test/java'
+    }
+  }
 
   it do
     should include_class('boxen::config')
 
-    should contain_package('jre-7u51.dmg').with({
+    should contain_package('jre-7u42.dmg').with({
       :ensure   => 'present',
       :alias    => 'java-jre',
       :provider => 'pkgdmg',
-      :source   => 'https://s3.amazonaws.com/boxen-downloads/java/jre-7u51-macosx-x64.dmg'
+      :source   => 'https://downloads.test/java/jre-7u42-macosx-x64.dmg'
     })
 
-    should contain_package('jdk-7u51.dmg').with({
+    should contain_package('jdk-7u42.dmg').with({
       :ensure   => 'present',
       :alias    => 'java',
       :provider => 'pkgdmg',
-      :source   => 'https://s3.amazonaws.com/boxen-downloads/java/jdk-7u51-macosx-x64.dmg'
+      :source   => 'https://downloads.test/java/jdk-7u42-macosx-x64.dmg'
     })
 
     should contain_file('/test/boxen/bin/java').with({