Add missing javadoc required by Java 8

Fixes #138
include_class is deprecated in favor of java_import

More details: http://jira.codehaus.org/browse/JRUBY-3797
It is not a good idea to compare strings as if they were numbers.

"1" > "0" == true
"9" > "100" == true
There is no need to call INT.to_s
Merge pull request #160 from juniorz/javadoc

Fix build for JDK 8
Merge pull request #164 from juniorz/deprecate

include_class is deprecated in favor of java_import
Merge pull request #166 from juniorz/bad_conversions

Bad conversions