Does Closing the InputStream of a Socket Also Terminate the Socket Connection?

Does closing the InputStream of a Socket terminate the socket connection?

Socket socket = new Socket("localhost", 8080);
InputStream inputStream = socket.getInputStream();
inputStream.close(); // Closing the InputStream

In Java, closing the InputStream of a socket does not automatically close the socket connection itself. The InputStream is a channel for receiving data, and closing it merely signifies that you will no longer read from it. The underlying Socket remains open until explicitly closed.

Socket socket = new Socket("localhost", 8080);
try (InputStream inputStream = socket.getInputStream()) {
   // Your data reading logic here
} catch (IOException e) {
   e.printStackTrace();
} finally {
   socket.close(); // Close the socket at the end
}

Causes

• The InputStream is designed to allow reading from the socket. Closing the InputStream does not affect the connection state of the socket.
• In Java, a Socket operates independently of its associated streams (InputStream/OutputStream). Hence, managing each stream does not imply managing the lifecycle of the Socket.
• Closing the InputStream can lead to a scenario where the socket remains open, but the application can no longer read data from it.

Solutions

• To properly manage resources, always ensure to close both the InputStream and the Socket to prevent resource leaks.
• Use the try-with-resources statement to automatically close the InputStream and Socket when you are done with them. Example: try (Socket socket = new Socket("localhost", 8080); InputStream inputStream = socket.getInputStream()) { // Read from the input stream } catch (IOException e) { e.printStackTrace(); }

Mistake: Failing to close the socket after closing the InputStream, leading to resource leaks.

Solution: Always ensure to explicitly close the Socket after completing the data processing.

Mistake: Assuming the socket connection is terminated by closing the InputStream, leading to potential confusion in application logic.

Solution: Clarify the socket and stream lifecycle in your application design and documentation.