From Forum Nokia Wiki

The default phone web browser can be invoked from within the Java ME application by using javax.microedition.midlet.MIDlet.platformRequest().

On some devices the MIDlet has to be closed (for example on Series 40 devices), before the browser can be launched. The application can take this into account by checking the return value of this method call. The value is true, if the MIDlet suite MUST first exit before the content can be fetched.

The following code is used for invoking the web browser.

String url = "http://forum.nokia.com";
platformRequest(url);