ClassLoader myBundleClassloader = 
		Thread.currentThread().getContextClassLoader();

Class<SomeClassInMyBundle> classFromBundle = 
		SomeClassInMyBundle.class;

ClassLoader classloaderWithSomeClassFromBundle = classFromBundle.getClassLoader();

Thread.currentThread().setContextClassLoader(
		classloaderWithSomeClassFromBundle);

final String applicationName = "myapp";
LoginContext lc;
try {

	lc = new LoginContext(applicationName, subject, 
			jaasCallbackHandler, configuration);

} catch (LoginException e) {

	LOGGER.error("LoginContext#<init> failed because LoginException,
		username="+ suppliedUsername, e);
	return false;

} finally {
	Thread.currentThread().setContextClassLoader(myBundleClassloader);
}

try {
	lc.login();
	LOGGER.info("login success for username=" + suppliedUsername);
	return true;
} catch (LoginException e) {

	LOGGER.error("LoginContext#login failed because LoginException,
		username="+ suppliedUsername, e);

	return false;
}