If the jvm gc an unclosed socket instance what would happen to the underlying tcp connection?

Question

If there is a unused socket instance, but it is not closed.

If the jvm would gc it?

If yes ,whether the tcp connection would close automatically?

Answer 1

The garbage collection will call finalize() which in turn closes the connection.

See java.net.AbstractPlainSocketImpl:

   protected void finalize() throws IOException {
        close();
    }

Almost like magic.