Using nv-websocket-client on Android

Question

I am testing nv-websocket-client on Android using Android Studio 2.2.3/JRE1.8.0_76.

My code is basically the same as the echo sample application in the README.md file. The class runs fine under Java 8 Update 111, but fails under Android Studio. I walked the code in debug mode and it failed at:

Source:com/neovisionaries/ws/client/Address.java:36

InetSocketAddress toInetSocketAddress()
{
    return new InetSocketAddress(mHost, mPort);// mHost = "echo.websocket.org", mPort = 80.
}

Error message in Android Studio:

Method threw 'java.lang.NullPointerException' exception. Cannot evaluate java.net.InetSocketAddress.toString()

Any idea what I did wrong here?

My Test Class:

public class TestWS {

private String m_msg;
private String m_uriStr; // = "ws://echo.websocket.org";
private static final int TIMEOUT = 5000;

public TestWS(String uriStr) {
    m_uriStr = uriStr;
    m_msg = "";
}

public void RunTest() {
    try {
        // Connect to the echo server.
        WebSocket ws = connect();
        ws.sendText("This is a test");
        Thread.sleep(1000); // Make sure m_msg is updated before function return.
        ws.disconnect();
    }
    catch(Exception ex)
    {
        m_msg += "Exception: " + ex.getMessage(); // getMessage() returns null.
    }
}

private WebSocket connect() throws IOException, WebSocketException
{
    return new WebSocketFactory()
            .setConnectionTimeout(TIMEOUT)
            .createSocket(m_uriStr)
            .addListener(new WebSocketAdapter() {
                // A text message arrived from the server.
                @Override
                public void onTextMessage(WebSocket websocket, String message) {
                    m_msg += "Echo: " + message;
                }
            })
            .addExtension(WebSocketExtension.PERMESSAGE_DEFLATE)
            .connect(); // <= failed in this function.
}

public String GetMsg(){
    return m_msg;
}
}