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PrivilegedActionException trying to invoke a signed Java applet from JavaScript

First off, I am not a Java developer. I had to create a Java applet to invoke some code in a native DLL I wrote from the browser.
I use JNA to load a native DLL and invoke its methods.
I have signed the applet using a self-signed certificate.
The browser asks me whether or not to allow the execution of the applet.
The applet code which loads my DLL is enclosed within AccessController.doPrivileged block.
Like this:
public String Test()
{
pHelper = AccessController.doPrivileged(new PrivilegedAction<IHelper>()
{
#Override
public IHelper run()
{
return (IHelper)Native.loadLibrary("Helper", IHelper.class);
}
});
return "test";
}
The code works fine when debugged inside Eclipse.
It does not work when invoked from JavaScript. Causes PrivilegedActionException.
If I remove the entire AccessController.doPrivileged block and leave return "test" only, the code runs when invoked from JavaScript. Any code that doesn't require privileges runs fine when invoked from JavaScript.
Tested from Chrome version 40.something and Firefox 36 on Windows 8.1 64-bit.
The native DLL is 32-bit as well as JRE used to run the applet.
Any tips?

I have never resolved this particular mystery. However, I was able to find a workaround, thanks to my applet design specification which doesn't require exposing any applet methods which need to be invoked to perform privileged operations.
I have found that executing privileged operations inside the applet init() function will work. Only privileged operations executed by invoking from JavaScript seem to cause problems. Consider the following code.
public class MyApplet extends JApplet {
private IHelper pHelper = null;
private MyReturnedInfo pInfo = null;
public void init() {
pHelper = (IHelper)Native.loadLibrary("Helper", IHelper.class);
if (pHelper != null) {
pInfo = pHelper.GetInfo();
}
}
public String GetInfoString() {
if (pInfo != null) {
// need to call toString to convert from native wide char to something JavaScript will be able to interpret
return pInfo.MyInfoString.toString();
}
return null;
}
}
Upon loading this applet, calling document.myApplet.GetInfoString() from JavaScript (providing the applet has an ID "myApplet") will return the required information.
Interestingly though, after signing the applet with a certificate issued by a trusted authority such as VeriSign, even this would not work in IE, while it would work properly in FF and Chrome. I have seen signed Java applets which work fine when called from JavaScript in IE, but I guess my applet is special because it requires all-permissions attribute in the manifest and IE probably doesn't like that. It's a guess. However, I have never found the real reason for that either, because I was able to resort to another workaround. :) If you are reading this answer then I bet you are interested in it as well.
Java applets allow us to provide additional parameters which we are able to obtain by calling this.getParameter() from inside the init() function. Also, if we allow the applet to call JavaScript functions from our HTML document by using mayscript attribute, we can easily combine these two facts to provide the JavaScript function for applet to call after the information from our native DLL has been obtained.
Let's say that in our HTML, we define the JavaScript like this.
<script type="text/javascript" src="https://www.java.com/js/deployJava.js"></script>
<script type="text/javascript">
var attributes = {
id: "myApplet",
name: "myApplet",
code: "MyApplet.class",
mayscript: "true",
scriptable: "true",
archive: "/path(s)/to/jar(s)",
width: 0,
height: 0
};
var params = {
"AppletReady": "appletInitialized",
};
// For convenience, it's easier to deploy the applet using deployJava,
// so it writes the applet HTML tag for us after checking if Java is installed.
// We have included it above.
deployJava.runApplet(attributes, params, "1.8.0");
function appletInitialized(myString, someOtherArgument) {
// do something with your parameters
// NOTE: do NOT call alert() from this function!
// Because it will most likely cause your browser to freeze,
// I've found that's also one of the things Java doesn't like.
};
</script>
Then, we modify the Java applet code to look like this.
public class MyApplet extends JApplet {
private IHelper pHelper = null;
private MyReturnedInfo pInfo = null;
public void init() {
// Read the AppletReady parameter as passed from JavaScript
String paramKey = "AppletReady";
String jsLoadedCallback = this.getParameter(paramKey);
// Load the library and get the information
pHelper = (IHelper)Native.loadLibrary("Helper", IHelper.class);
if (pHelper != null) {
pInfo = pHelper.GetInfo();
if (pInfo != null && jsLoadedCallback != null) {
// Get the window which contains "this" applet
JSObject jsObject = JSObject.getWindow(this);
// Call the provided JavaScript function.
// You can use as many parameters as you need.
jsObject.call(jsLoadedCallback, new Object[] {
pInfo.MyInfoString.toString(),
pInfo.SomeOtherStringMaybe.toString()
});
}
}
}
}
However, if you need the applet to call your native DLL methods dynamically during runtime (I.E. you require the applet to expose functions which need to be called to perform privileged operations dynamically) this solution will not work for you and you are out of luck, at least if using JNA.

Calling a javascript function out of java

Im trying to call a javascript function out of my Vaadin Portlet.
lets say I have an HTML file witch is located in my project ;
homepage.html
<html>
...
<script type="text/javascript">
...
function foo(String msg)
{
alert(msg);
}
...
</script>
...
</html>
the page in Embedded in my Portlet via the Vaadin Embedded Browser
how do I call the function foo(String msg) out of my java application
do i need to import/read the homepage.html file and just call it or is it something else I have to do ?

firstly you need to get the script body;
then you can user javax.script.ScriptEngineManager to solve your problem javax.script.*
pseudo code
import javax.script.*;
ScriptEngine engine =
new ScriptEngineManager().getEngineByName("javascript");
String script = getScript(path_to_html);
engine.eval(script);

The simplest way to include an external javascript file into a Vaadin application is to override the Application#writeAjaxPageHtmlVaadinScripts method.
To call a javascript function from the Vaadin server-side code, you call Window#executeJavascript
#Override
protected void writeAjaxPageHtmlVaadinScripts(Window window,
String themeName, Application application, BufferedWriter page,
String appUrl, String themeUri, String appId,
HttpServletRequest request) throws ServletException, IOException {
page.write("<script type=\"text/javascript\">\n");
page.write("//<![CDATA[\n");
page.write("document.write(\"<script language='javascript' src='" + appUrl + "/VAADIN/scripts/example.js'><\\/script>\");\n");
page.write("//]]>\n</script>\n");
super.writeAjaxPageHtmlVaadinScripts(window, themeName, application,
page, appUrl, themeUri, appId, request);
}
NB : I have never used Vaadin as a Portlet, but a quick look suggests that this should work OK.
However, this approach is rather rudimentary, and only suitable for a quick hack/proof-of-concept: if you want to so anything more sophisticated, then developing your own Vaadin widget is correct approach. It gives you the power of GWT and JSNI, and gives you a much finer grain of control : See The Book Of Vaadin for more details.

Refer to following links, these provides API for doing what you want to do,
http://www.ibm.com/developerworks/java/library/j-5things9/index.html
http://metoojava.wordpress.com/2010/06/20/execute-javascript-from-java/

Call java method in javascript without html firebug extension

I'm trying to develop an extension for firebug. I want to call a java method in this extension but there is no html in it so I can't use the applet-html solution.
Here is my java Applet :
import java.applet.Applet;
import javax.swing.JOptionPane;
public class MyApplet extends Applet {
public void init() {
super.init();
System.out.println("init something");
}
public String jsCall(String hello) {
System.out.println("this method is called by a js function and say :"
+ hello);
Thread t = new Thread(new Runnable(){
public void run(){
JOptionPane jop1 = new JOptionPane();
jop1.showMessageDialog(null, "Message informatif", "Information", JOptionPane.INFORMATION_MESSAGE);
}
});
t.start();
return "lala";
}
}
I try this:
var applet = document.createElement("applet");
applet.setAttribute("code","file:///home/dacostam/z_test/firebug-extension-examples-0bdcf15/helloamd#janodvarko.cz/chrome/content/MyApplet.class");
applet.setAttribute("id","javaToJavascriptApplet");
applet.setAttribute("mayscript","true");
applet.jsCall("HelloWorld"); //jsCall not a function
And this:
var dom = document.implementation.createDocument('http://www.w3.org/1999/xhtml', 'html', null);
dom.appendChild(applet);
dom.javaToJavascriptApplet.jsCall("HelloWorld"); //jsCall not a function
The document is not like usual there is no body or html in it.
Is there an other way to call java in javascript instead of the applet-html solution?
Or is there a way to do it with this method but otherwise?
If you need more information, I'm here.
Thanks.
Edit:
It would be to long to explain you what the program do, just keep in mind that it's inevitably in java, I just need to call a method which take a parameter string and return a string or eventually void.
Edit2:
Sorry I have not thought of that, java needs to run on the client.

If your requirement is to make a call from JavaScript to your Java application, you need to clarify where does your Java app needs to run.
If Java needs to run on the client (same machine as your Firebug), it looks like you are either stuck with an applet or you need to be building a tiny webservice in your Java so you can talk to it through a web API on localhost.
If your Java can sit on a server somewhere, you could talk to your Java application through a web API (similarly to the second option above).

How to execute JavaScript on Android?

I have code which uses ScriptEngineManager, ScriptEngine class for executing JavaScript code using Java. But it works fine in Java SE, and doesn't work in Android - SDK show error of missing classes. Is it possible to execute JS code in Android? Thank you.

AndroidJSCore is a great one. And here is another little library I wrote for evaluating JavaScript:
https://github.com/evgenyneu/js-evaluator-for-android
jsEvaluator.evaluate("function hello(){ return 'Hello world!'; } hello();", new JsCallback() {
#Override
public void onResult(final String result) {
// get result here (optional)
}
});
It creates a WebView behind the scenes. Works on Android version 3 and newer.

You can use Webview which inherits View class. Make an XML tag and use findViewById() function to use in the activity. But to use the JavaScript, you can make a HTML file containing the JavaScript code. The example blelow might help.
Webview browser=(Webview) findViewById(R.main.browser); //if you gave the id as browser
browser.getSettings().setJavaScriptEnabled(true); //Yes you have to do it
browser.loadUrl("file:///android_asset/JsPage.html"); //If you put the HTML file in asset folder of android
Remember that the JS will run on WebView, not in native environment, thus you might experience a lag or slow FPS in emulator. However when using on an actual phone, the code may run fast, depending on how fast is your phone.

http://divineprogrammer.blogspot.com/2009/11/javascript-rhino-on-android.html will get you started. ScriptEngine is a java thing. Android doesn't have a JVM but a DalvikVM which is not identical but similar.

UPDATE 2018: AndroidJSCore has been superseded by LiquidCore, which is based on V8. Not only does it include the V8 engine, but all of Node.js is available as well.
Original answer:
AndroidJSCore is an Android Java JNI wrapper around Webkit's JavaScriptCore C library. It is inspired by the Objective-C JavaScriptCore Framework included natively in iOS 7. Being able to natively use JavaScript in an app without requiring the use of JavaScript injection on a bloated, slow, security-constrained WebView is very useful for many types of apps, such as games or platforms that support plugins. However, its use is artificially limited because the framework is only supported on iOS. Most developers want to use technologies that will scale across both major mobile operating systems. AndroidJSCore was designed to support that requirement.
For example, you can share Java objects and make async calls:
public interface IAsyncObj {
public void callMeMaybe(Integer ms, JSValue callback) throws JSException;
}
public class AsyncObj extends JSObject implements IAsyncObj {
public AsyncObj(JSContext ctx) throws JSException { super(ctx,IAsyncObj.class); }
#Override
public void callMeMaybe(Integer ms, JSValue callback) throws JSException {
new CallMeLater(ms).execute(callback.toObject());
}
private class CallMeLater extends AsyncTask<JSObject, Void, JSObject> {
public CallMeLater(Integer ms) {
this.ms = ms;
}
private final Integer ms;
#Override
protected JSObject doInBackground(JSObject... params) {
try {
Thread.sleep(ms);
} catch (InterruptedException e) {
Thread.interrupted();
}
return params[0];
}
#Override
protected void onPostExecute(JSObject callback) {
JSValue args [] = { new JSValue(context,
"This is a delayed message from Java!") };
try {
callback.callAsFunction(null, args);
} catch (JSException e) {
System.out.println(e);
}
}
}
}
public void run() throws JSException {
AsyncObj async = new AsyncObj(context);
context.property("async",async);
context.evaluateScript(
"log('Please call me back in 5 seconds');\n" +
"async.callMeMaybe(5000, function(msg) {\n" +
" alert(msg);\n" +
" log('Whoomp. There it is.');\n" +
"});\n" +
"log('async.callMeMaybe() has returned, but wait for it ...');\n"
);
}

I was also looking for a way to run javascript on Android and came across j2v8 library. This is a java wrapper for Google's v8 engine.
To use it add a dependency:
compile 'com.eclipsesource.j2v8:j2v8_android:3.0.5#aar'
It has pretty simple api, but I haven't found any docs online apart from javadoc in maven repository. The articles on their blog are also useful.
Code sample from this article:
public static void main(String[] args) {
V8 runtime = V8.createV8Runtime();
int result = runtime.executeIntegerScript(""
+ "var hello = 'hello, ';\n"
+ "var world = 'world!';\n"
+ "hello.concat(world).length;\n");
System.out.println(result);
runtime.release();
}

The javax.script package is not part of the Android SDK. You can execute JavaScript in a WebView, as described here. You perhaps can use Rhino, as described here. You might also take a look at the Scripting Layer for Android project.

You can use Rhino library to execute JavaScript without WebView.
Download Rhino first, unzip it, put the js.jar file under libs folder. It is very small, so you don't need to worry your apk file will be ridiculously large because of this one external jar.
Here is some simple code to execute JavaScript code.
Object[] params = new Object[] { "javaScriptParam" };
// Every Rhino VM begins with the enter()
// This Context is not Android's Context
Context rhino = Context.enter();
// Turn off optimization to make Rhino Android compatible
rhino.setOptimizationLevel(-1);
try {
Scriptable scope = rhino.initStandardObjects();
// Note the forth argument is 1, which means the JavaScript source has
// been compressed to only one line using something like YUI
rhino.evaluateString(scope, javaScriptCode, "JavaScript", 1, null);
// Get the functionName defined in JavaScriptCode
Object obj = scope.get(functionNameInJavaScriptCode, scope);
if (obj instanceof Function) {
Function jsFunction = (Function) obj;
// Call the function with params
Object jsResult = jsFunction.call(rhino, scope, scope, params);
// Parse the jsResult object to a String
String result = Context.toString(jsResult);
}
} finally {
Context.exit();
}
You can see more details at my post.

Given that ScriptEngineManager and ScriptEngine are part of the JDK and Android SDK is not the same thing as the JDK I would say that you can't use these classes to work with JavaScript under Android.
You can check the Android SDK's reference documentation/package index to see what classes are included (what can you work on Android out of the box) and which of them are missing.

I just found the App JavaScript for Android, which is the Rhino JavaScript engine for Java. It can use all Java-classes, so it has BIG potential. The problem is it might be slow, since it is not really optimized (heavy CPU load). There is another JavaScript engine named Nashorn, but that unfortunately doesn't works on Google's DalvikVM Java engine (does not support the optimizations of Oracle Java engine). I hope Google keeps up with that, I would just love it!

If you want to run some javascript code on chrome browser as per the question copy this code and paste it into address bar:
data:text/html, <html contenteditable> <title> Notepad </title> <script> alert('Abhasker Alert Test on Mobile'); </script> </html>

How can I fill out an online form with Java?

My cell phone provider offers a limited number of free text messages on their website. I frequently use the service although I hate constantly having a tab open in my browser.
Does anyone know/point me in the right direction of how I could create a jar file/command line utility so I can fill out the appropriate forms on the site. I've always wanted to code up a project like this in Java, just in case anyone asks why I'm not using something else.
Kind Regards,
Lar

Try with Webdriver from Google or Selenium.

Sounds like you need a framework designed for doing functional testing. These act as browsers and can navigate web sites for testing and automation. You don't need the testing functionality, but it would still serve your needs.
Try HtmlUnit, or LiFT, which is a higher-level abstraction built on HtmlUnit.

Use Watij with the Eclipse IDE. When your done, compile as an .exe or run with a batch file.
Here is some sample code I wrote for filling in fields for a Google search, which can be adjusted for the web form you want to control :
package goog;
import junit.framework.TestCase;
import watij.runtime.ie.IE;
import static watij.finders.SymbolFactory.*;
public class GTestCases extends TestCase {
private static watij.runtime.ie.IE activeIE_m;
public static IE attachToIE(String url) throws Exception {
if (activeIE_m==null)
{
activeIE_m = new IE();
activeIE_m.start(url);
} else {
activeIE_m.goTo(url);
}
activeIE_m.bringToFront();
return (activeIE_m);
}
public static String getActiveUrl () throws Exception {
String currUrl = activeIE_m.url().toString();
return currUrl;
}
public void testGoogleLogin() throws Exception {
IE ie = attachToIE("http://google.com");
if ( ie.containsText("/Sign in/") ) {
ie.div(id,"guser").link(0).click();
if ( ie.containsText("Sign in with your") ||
ie.containsText("Sign in to iGoogle with your")) {
ie.textField(name,"Email").set("test#gmail.com");
ie.textField(name,"Passwd").set("test");
if ( ie.checkbox(name,"PersistentCookie").checked() ){
ie.checkbox(name,"PersistentCookie").click();
}
ie.button(name,"signIn").click();
}
}
System.out.println("Login finished.");
}
public void testGoogleSearch() throws Exception {
//IE ie = attachToIE( getActiveUrl() );
IE ie = attachToIE( "http://www.google.com/advanced_search?hl=en" );
ie.div(id,"opt-handle").click();
ie.textField(name,"as_q").set("Watij");
ie.selectList(name,"lr").select("English");
ie.button(value,"Advanced Search").click();
System.out.println("Search finished.");
}
public void testGoogleResult() throws Exception {
IE ie = attachToIE( getActiveUrl() );
ie.link(href,"http://groups.google.com/group/watij").click();
System.out.println("Followed link.");
}
}

It depends on how they are sending the form information.
If they are using a simple GET request, all you need to do is fill in the appropriate url parameters.
Otherwise you will need to post the form information to the target page.

You could use Watij, which provides a Java/COM interface onto Internet Explorer. Then write a small amount of Java code to navigate the form, insert values and submit.
Alternatively, if it's simple, then check out HttpClient, which is a simple Java HTTP client API.
Whatever you do, watch out that you don't contravene your terms of service (easy during testing - perhaps you should work against a mock interface initially?)

WebTest is yet another webapp testing framework that may be easier to use than the alternatives cited by others.

Check out the Apache Commons Net Package. There you can send a POSt request to a page. This is quite low level but may do what you want (if not you might check out the functional testing suites but it is probably not as easy to dig into).

As jjnguy says, you'll need to dissect the form to find out all the parameters.
With them you can form your own request using Apache's HTTP Client and fire it off.