You can use ServerSocketclass in Java to create a Server which can accept requests.
Blocking methods in Java are those methods which block the executing thread until their operation finished.
A famous example of blocking method is InputStream read() method which blocks until all data from InputStream has been read completely.
This is the standard HTTP Server, its simple because HTTP is stateless, which means it doesn't need to remember previous connection, all it care for new incoming connections. This is endless cycle until server is stopped.
It's better to use BufferedReader because browser will send multiple line.