What does the java.net.SocketInputStream.socketRead0() API do? Why is it showing up frequently in thread dumps? Why is it reported in thread dump analysis tools like fastThread.io? Is it something that I need to be concerned about? What are the potential solutions to this problem? Let’s find answers to these questions.
What Does the SocketInputStream.socketRead0() API Do?
It’s always easy to remember new concepts through real-life analogies. Suppose you are calling your wife or girlfriend on the phone. Once the call gets connected, if she is in a good mood, you will get the response: “Hello, Honey, how are you?” If your call got connected when she is in middle of doing work (say she is in her office, picking up kids, at the gym, etc.), there might be a delay in her response: “Hello, Honey...” Suppose your call got connected when she is upset. You might get a response after several seconds/minutes. So, the time you are waiting since the moment call got connected until the moment you hang up the call is basically the socketRead0() API. (Thanks to Douglas Spath from IBM for giving this beautiful example to explain this SocketRead0() API.)