Java HTTP connection seems to remain open

Question

I have created a connection in Java to private API

String urlRequest = "https://localhost:8080/orders/create";
String username = "test";
String password = "test";
String certificatePass = "test";
byte[] authEncBytes = Base64.getEncoder().encode((username + ":" + password).getBytes());

URL url = new URL(urlRequest);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setRequestProperty("Authorization", "Basic " + new   String(authEncBytes));
conn.setRequestProperty("Content-Type", "application/json");
conn.setRequestProperty("Accept", "application/json");

conn.setDoOutput(true);
conn.setDoInput(true);

InputStream is = conn.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
is.close();

After the initial pass, connection seems to remain open, because when running the code from the start, HttpURLConnection throws an Exception at conn.setRequestMethod("POST");,

"Can't reset method: already connected"

I managed to somehow close it now, I don't know what have I done, but does anyone know what the issue here could have been? I restarted my PC in the meantime, and it would still thrown an exception at conn.setRequestMethod("POST");, I don't understand how can a connection persist between restarts. I also tried adding conn.disconnect() before trying to set request method, and that didn't seem to work either. The only thing that made a difference was changing the URL, but I could only connect once, every next time running the code would give me the same exception.

How do I close the connection properly?

because it only happens on debug mode and not in running mode, though the reason is unknown. you can check https://stackoverflow.com/questions/19766327/android-java-net-protocolexception-connection-already-established/28485029#28485029 — MohammadReza Alagheband, Sep 20 '18 at 12:02
Could have been it, but I just tried adding a breakpoint there again, and it doesn't seem to happen, so no idea. — lovrodoe, Sep 20 '18 at 12:11
Yes, I also tried to reproduce the issue but it seems it only happens at some random times while debugging — MohammadReza Alagheband, Sep 20 '18 at 12:12
Possible. Annoying though, I've just spent several hours trying to debug it. Thanks — lovrodoe, Sep 20 '18 at 12:13
you're welcome, If you find any answer please post it here. thanks — MohammadReza Alagheband, Sep 20 '18 at 12:14

score 3 · Accepted Answer · answered Sep 26 '18 at 12:41

Had the issue again today and the problem was with expressions in debug mode. I was calling connect there, I guess while testing so in case anyone didn't know, expressions do affect your variables and can change what's in memory. For instance, having:

int a = 5;
System.out.println(a);

in your code and having a = 6 in your Expressions list, System.out.println(a) will print 6, not 5.

Deleting expressions fixed my problem.

score 0 · Answer 2 · answered Sep 20 '18 at 12:15

0

I think your question already has an answer here.

Closing URLConnection and InputStream correctly?

Close your connection at end of the code and don't do it before setRequest method.

answered Sep 20 '18 at 12:15

Ragesh

205
3
11

The thing is I didn't even establish a connection in the first place because I have yet to add a client certificate, so I'm not getting past the handshake. I never called connection.connect() either. – lovrodoe Sep 20 '18 at 12:23
You no need to call connect() because you are using getInputStream() Check this link: https://docs.oracle.com/javase/tutorial/networking/urls/connecting.html – Ragesh Sep 20 '18 at 12:32
1

Thanks, input stream may have been the issue. – lovrodoe Sep 20 '18 at 12:37
You are welcome. If the answer was correct just tick it to help others. – Ragesh Sep 20 '18 at 12:45

Java HTTP connection seems to remain open

2 Answers2