#vulnerable code 
                             @Override
	public boolean cancel() {
		boolean cancelled = super.cancel();
		if (!cancelled) {
			return false;
		}
		synchronized (signal) {
			signal.notifyAll();
		}
		// Try to force-quit the connection
		if (connection != null) {
			setTimeout(1);
			connection.disconnect();
		}
		return true;
	} 
                            #location 13 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                             @Override
	public boolean cancel() {
		synchronized (signal) {
			boolean cancelled = super.cancel();
			if (!cancelled) {
				return false;
			}
			signal.notifyAll();
			// Try to force-quit the connection
			if (connection != null) {
				setTimeout(1);
				connection.disconnect();
			}
		}
		return true;
	}