Sample Project in Java and Sample Project in Scala are guides to setting up Maven and SBT projects and include simple implementations of a word count application.
Monitoring Wikipedia Edits is a more complete example of a streaming analytics application.
Building real-time dashboard applications with Apache Flink, Elasticsearch, and Kibana is a blog post at elastic.co showing how to build a real-time dashboard solution for streaming data analytics using Apache Flink, Elasticsearch, and Kibana.
The Flink training website from data Artisans has a number of examples. See the hands-on sections, and the exercises.
The Flink sources include a number of examples for both streaming ( java / scala ) and batch ( java / scala ). These instructions explain how to run the examples.