How do I use Java Generics with Lookup?

As of NetBeans 6, a number of convenience methods have been added to lookup, and support for Java generics has been added to Lookup. The following are differences:

The new style also works well with for-loops and avoids casts:

for (SomeService s : Lookup.getDefault().lookupAll(SomeService.class)) {
    // ...
}
// ...
SomeSingleton s = Lookup.getDefault().lookup(SomeSingleton.class);
if (s != null) {
    // ...
}