Here's a simple micro-service example which implements an API for a product catalog.
The API allows you to list all products, retrieve details for a particular product and to add a new product. Product information is provided in JSON.
List all products:
GET /products
Get a product:
GET /products/<product_id>
Add a product:
POST /products
Update a product:
PUT /products/<product_id>
To build and run it:
docker build -t poc-product-service .
docker run -t -i -p 8080:8080 poc-product-service
Run the server either in your IDE or on the command line, then open your browser and hit list products to start playing with the API.