#vulnerable code 
                                @Override
    public void startAppiumServer(String host) throws Exception {
        System.out.println(
                "**************************************************************************\n");
        System.out.println("Starting Appium Server on host " + host);
        System.out.println(
                "**************************************************************************\n");
        String serverPath = CapabilityManager.getInstance().getAppiumServerPath(host);
        String serverPort = CapabilityManager.getInstance().getAppiumServerPort(host);
        if (serverPath == null
                && serverPort == null) {
            System.out.println("Picking Default Path for AppiumServiceBuilder");
            new Api().getResponse("http://" + host + ":4567"
                    + "/appium/start").body().string();
        } else if (serverPath != null && serverPort != null) {
            System.out.println("Picking UserSpecified Path & Port for AppiumServiceBuilder");
            new Api().getResponse("http://" + host + ":4567"
                    + "/appium/start?URL=" + serverPath
                    + "&PORT=" + serverPort).body().string();
        } else if (serverPath != null) {
            System.out.println("Picking UserSpecified Path "
                    + "& Using default Port for AppiumServiceBuilder");
            new Api().getResponse("http://" + host + ":4567"
                    + "/appium/start?URL=" + serverPath).body().string();
        } else if (serverPort != null) {
            System.out.println("Picking Default Path & User Port for AppiumServiceBuilder");
            new Api().getResponse("http://" + host + ":4567"
                    + "/appium/start?PORT=" + serverPort).body().string();
        }

        boolean status = Boolean.getBoolean(new JSONObject(new Api().getResponse("http://" + host + ":4567"
                + "/appium/isRunning").body().string()).get("status").toString());
        if (status) {
            System.out.println(
                    "***************************************************************\n");
            System.out.println("Appium Server started successfully on  " + host);
            System.out.println(
                    "****************************************************************\n");
        }
    } 
                            #location 19 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Override
    public void startAppiumServer(String host) throws Exception {
        System.out.println(
                "**************************************************************************\n");
        System.out.println("Starting Appium Server on host " + host);
        System.out.println(
                "**************************************************************************\n");
        String serverPath = CapabilityManager.getInstance().getAppiumServerPath(host);
        String serverPort = CapabilityManager.getInstance().getAppiumServerPort(host);
        if (serverPath == null
                && serverPort == null) {
            System.out.println("Picking Default Path for AppiumServiceBuilder");
            new Api().getResponse("http://" + host + ":"
                    + getRemoteAppiumManagerPort(host)
                    + "/appium/start").body().string();
        } else if (serverPath != null && serverPort != null) {
            System.out.println("Picking UserSpecified Path & Port for AppiumServiceBuilder");
            new Api().getResponse("http://" + host + ":"
                    + getRemoteAppiumManagerPort(host)
                    + "/appium/start?URL=" + serverPath
                    + "&PORT=" + serverPort).body().string();
        } else if (serverPath != null) {
            System.out.println("Picking UserSpecified Path "
                    + "& Using default Port for AppiumServiceBuilder");
            new Api().getResponse("http://" + host + ":"
                    + getRemoteAppiumManagerPort(host)
                    + "/appium/start?URL=" + serverPath).body().string();
        } else if (serverPort != null) {
            System.out.println("Picking Default Path & User Port for AppiumServiceBuilder");
            new Api().getResponse("http://" + host + ":"
                    + getRemoteAppiumManagerPort(host)
                    + "/appium/start?PORT=" + serverPort).body().string();
        }

        boolean status = Boolean.getBoolean(new JSONObject(new Api()
                .getResponse("http://" + host + ":"
                        + getRemoteAppiumManagerPort(host)
                        + "/appium/isRunning").body().string()).get("status").toString());
        if (status) {
            System.out.println(
                    "***************************************************************\n");
            System.out.println("Appium Server started successfully on  " + host);
            System.out.println(
                    "****************************************************************\n");
        }
    }