[java] How should I resolve java.lang.IllegalArgumentException: protocol = https host = null Exception?

I am working on a SSL client server program and I have to reuse the following method.

private boolean postMessage(String message){
    try{ 
         String serverURLS = getRecipientURL(message);

         serverURLS = "https:\\\\abc.my.domain.com:55555\\update";

         if (serverURLS != null){
             serverURL = new URL(serverURLS);
         }

        HttpsURLConnection conn = (HttpsURLConnection)serverURL.openConnection();

        conn.setHostnameVerifier(new HostnameVerifier() { 
        public boolean verify(String arg0, SSLSession arg1) {
            return true;
        } 
        });

        conn.setDoOutput(true);

        OutputStream os = conn.getOutputStream();

        OutputStreamWriter wr = new OutputStreamWriter(os);

        wr.write(message);

        wr.flush();

        if (conn.getResponseCode() != HttpsURLConnection.HTTP_OK)
            return false;
        else
            return true;

    }

Here ServerURL is initialized as

private URL serverURL = null;

When I try to execute this method I get an exception at Line,

OutputStream os = conn.getOutputStream();

The exception is

java.lang.IllegalArgumentException: protocol = https host = null

What is the reason for this?

Might help some else - I came here because I missed putting two // after http:. This is what I had:

http:/abc.my.domain.com:55555/update

This code seems completely unnecessary:

String serverURLS = getRecipientURL(message);

serverURLS = "https:\\\\abc.my.domain.com:55555\\update";

if (serverURLS != null){
    serverURL = new URL(serverURLS);
}

1. serverURLS is assigned the result of getRecipientURL(message)
2. Then immediately you overwrite the value of serverURLS, making the previous statement a dead store
3. Then, because if (serverURLS != null) evaluates to true, since you just assigned the variable a value in the preceding statement, you assign a value to serverURL. It is impossible for if (serverURLS != null) to evaluate to false!
4. You never actually use the variable serverURLS beyond the previous line of code.

You could replace all of this with just:

serverURL = new URL("https:\\\\abc.my.domain.com:55555\\update");