#vulnerable code 
                                public void destroy()
    {
        for (Socket socket : sockets) {
            socket.setLinger(linger);
            socket.close();
        }
        sockets.clear();

        // Only terminate context if we are on the main thread
        if (isMain() && context != null) {
            context.term();
        }

        synchronized (this) {
            context = null;
        }
    } 
                            #location 4 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                                public void destroy()
    {
        for (Socket socket : sockets) {
            destroySocket(socket);
        }
        sockets.clear();
        // Only terminate context if we are on the main thread
        if (isMain() && context != null) {
            context.term();
            context = null;
        }
    }