How to use GWT $entry Function in JSNI?

Question

The $entry function in GWT is used to get uncaught exceptions reported from JavaScript to GWT.

What is the difference between the following $entry calls and which one is the correct one?

The following versions call instance Java functions.

Version 1:

public final native String test(double arg) /*-{
    var instance = this;

    var callExternal = $entry(function(arg) {
       return [email protected]::javaFunction(D)(arg);
    });

    var x = callExternal(arg);
}-*/;

Version 2:

public final native String test(double arg) /*-{
    var x = $entry([email protected]::javaFunction(D)(arg));
}-*/;

Is there a different use whether I use static or non static java functions?

Update:

The following versions call static Java functions.

Version 1:

public final native String test(double arg) /*-{

    var callExternal = $entry(function(arg) {
       [email protected]::javaFunction(D)(arg);
    });

    var x = callExternal(arg);
}-*/;

Version 2:

public final native String test(double arg) /*-{
    var x = $entry(@com.example.MyClass::staticJavaFunction(D)(arg));
}-*/; 

Answer 1

The second one is wrong: it calls the method then wraps the result. It's useless, possibly even broken.

$entry wraps a function in another function that uses a try/catch.