The *app example cookbooks are used with the AWS OpsWorks Getting Started Walkthroughs.
java: Installs either OpenJDK or Sun/Oracle Java - taken from https://github.com/opscode-cookbooks/java and adapted for OpsWorks. If you want to use Oracle Java, make sure to have the following in your custom JSON:
{ "java": { "oracle": { "accept_oracle_download_terms": true } } }