add two facts: java_libjvm_path java_default_home

* dirname containing base directory of java
* e.g. java binary is `${::java_default_home}/jre/bin/java`

* dirname containing `libjvm.so`
* Most people will use this for LD_LIBRARY_PATH

lib/facter/java_default_home.rb

@@ -0,0 +1,21 @@
+# Fact: java_default_home
+#
+# Purpose: get absolute path of java system home
+#
+# Resolution:
+#   Uses `readlink` to resolve the path of `/usr/bin/java` then returns subsubdir
+#
+# Caveats:
+#   Requires readlink
+#
+# Notes:
+#   None
+Facter.add(:java_default_home) do
+  confine :kernel => 'Linux'
+  setcode do
+    if Facter::Util::Resolution.which('readlink')
+      java_bin = Facter::Util::Resolution.exec('readlink -e /usr/bin/java').strip
+      java_default_home = File.dirname(File.dirname(File.dirname(java_bin)))
+    end
+  end
+end