gist for ask.electric-cloud.com question about jsni and accessing javascript from an ElectricCommander GWT plugin.

gistfile1.js

// In your javascript file
var sayHello = function(){
  alert("Hello World!");
}
    
// In your <Component>.java file
  import com.google.gwt.core.client.JavaScriptObject;
  public native JavaScriptObject callNative() /*-{
        $wnd.sayHello();
    }-*/;
    
// In the doInit()
callNative();