1. Getting started
2. Calling methods
3. Working with .NET Objects
4. Fields and Properties
5. Methods Arguments
6. Nested Types
7. Enums
8. Arrays and Collections
9. Embeding UI controls
10. Referencing libraries
11. Off-line activation
12. Events and Delegates
13. Disposing and Garabage Collection
14. .NET Configuration Files (AppConfig, WebConfig)
15. Exceptions, Debugging and Testing
16. Strongly-Typed Wrappers

    Calling Overloaded Method Passing Null Argument

    In some cases you might need to call a method – that has multiple overloads with the same number of arguments – passing null. Considering following case:

    public void MethodA(String arg)
    {
        Console.Out.WriteLine("Method with String argument called");
    }
    public void MethodA(Object arg)
    {
        Console.Out.WriteLine("Method with Object argument called");
    }
    public void MethodA(int? arg)
    {
        Console.Out.WriteLine("Method with nullable int argument called");
    }

    If you call MethodA passing “null” as argument .NET side will not be able to resolve which method should be called as in both overloads null can be passed. Ambigous invocation exception will be thrown. To overcome this issue Javonet introduces “NNull” type which allows to pass type-specific null value.

    How to call .NET method passing type-specific null value

    //To call MethodA with String argument passing null use the following syntax
    sampleObj.invoke("MethodA",new NNull("String"));
    
    //Or to call overload with generic int? argument
    sampleObj.invoke("MethodA",new NNull("Nullable`[System.Int32]"));

    See Live Example!