diff --git a/core/deployment/src/main/java/io/quarkus/deployment/dev/QuarkusDevModeLauncher.java b/core/deployment/src/main/java/io/quarkus/deployment/dev/QuarkusDevModeLauncher.java index 3d770034cc478..674320c9bd34b 100644 --- a/core/deployment/src/main/java/io/quarkus/deployment/dev/QuarkusDevModeLauncher.java +++ b/core/deployment/src/main/java/io/quarkus/deployment/dev/QuarkusDevModeLauncher.java @@ -369,6 +369,7 @@ protected void prepare() throws Exception { port = Integer.parseInt(debug); } } + int originalPort = port; if (port <= 0) { port = getRandomPort(); } @@ -376,19 +377,42 @@ protected void prepare() throws Exception { if (debug != null && debug.equalsIgnoreCase("client")) { args.add("-agentlib:jdwp=transport=dt_socket,address=" + debugHost + ":" + port + ",server=n,suspend=" + suspend); } else if (debug == null || !debug.equalsIgnoreCase("false")) { - // make sure the debug port is not used, we don't want to just fail if something else is using it - // we don't check this on restarts, as the previous process is still running + // if the debug port is used, we want to make an effort to pick another one + // if we can't find an open port, we don't fail the process launch, we just don't enable debugging + // Furthermore, we don't check this on restarts, as the previous process is still running + boolean warnAboutChange = false; if (debugPortOk == null) { - try (Socket socket = new Socket(getInetAddress(debugHost), port)) { - error("Port " + port + " in use, not starting in debug mode"); - debugPortOk = false; - } catch (IOException e) { - debugPortOk = true; + int tries = 0; + while (true) { + boolean isPortUsed; + try (Socket socket = new Socket(getInetAddress(debugHost), port)) { + // we can make a connection, that means the port is in use + isPortUsed = true; + warnAboutChange = warnAboutChange || (originalPort != 0); // we only want to warn if the user had not configured a random port + } catch (IOException e) { + // no connection made, so the port is not in use + isPortUsed = false; + } + if (!isPortUsed) { + debugPortOk = true; + break; + } + if (++tries >= 5) { + debugPortOk = false; + break; + } else { + port = getRandomPort(); + } } } if (debugPortOk) { + if (warnAboutChange) { + warn("Changed debug port to " + port + " because of a port conflict"); + } args.add("-agentlib:jdwp=transport=dt_socket,address=" + debugHost + ":" + port + ",server=y,suspend=" + suspend); + } else { + error("Port " + port + " in use, not starting in debug mode"); } }