skylot/jadx · error · SmaliDebuggerException

jdwp handshake bad reply

Error message

jdwp handshake bad reply

What it means

Error "jdwp handshake bad reply" thrown in skylot/jadx.

Source

Thrown at jadx-gui/src/main/java/jadx/gui/device/debugger/SmaliDebugger.java:647

					return new JDWP(sizes);
				}
			}
		} catch (IOException e) {
			throw new SmaliDebuggerException(e);
		}
		throw new SmaliDebuggerException("Failed to init JDWP.");
	}

	private static void handShake(OutputStream outputStream, InputStream inputStream) throws SmaliDebuggerException {
		byte[] buf;
		try {
			outputStream.write(JDWP.encodeHandShakePacket());
			buf = IOUtils.readNBytes(inputStream, 14);
		} catch (Exception e) {
			throw new SmaliDebuggerException("jdwp handshake failed", e);
		}
		if (buf == null || !JDWP.decodeHandShakePacket(buf)) {
			throw new SmaliDebuggerException("jdwp handshake bad reply");
		}
	}

	private MethodsWithGenericData getMethodBySig(long classID, String sig) {
		List<MethodsWithGenericData> methods = clsMethodMap.get(classID);
		if (methods != null) {
			for (MethodsWithGenericData method : methods) {
				if (sig.startsWith(method.name + "(") && sig.endsWith(method.signature)) {
					return method;
				}
			}
		}
		return null;
	}

	private int genID() {
		return idGenerator.getAndAdd(1);
	}

View on GitHub (pinned to e738a26571)

Solutions

1. Compare the reply bytes against the expected handshake string and include the received bytes (hex) in the error message for diagnosis.
2. If the reply is bad, close the socket and advise reconnecting the debugger, since the transport state is unrecoverable.

When it happens

Trigger: Thrown at jadx-gui/src/main/java/jadx/gui/device/debugger/SmaliDebugger.java:647 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• SSL/TLS and certificate errors — how TLS handshakes and certificate validation fail.

AI-assisted analysis of skylot/jadx@e738a26571 (2026-08-14). Data as JSON: /api/errors/da9f4257e02eed26. Report an issue: GitHub.