Java vs. C#

Primitives vs. Objects

Java
 
Java primitives cannot be assigned to 
reference types directly before Java 5.
class Test
{
    public static void main(String[] args) {
        int i = 123;
        Object o = i;      // error
        int j = (int) o;  // error
        System.out.println(3.toString());//error
    }
}

C#
 
C# provides a "unified type system".
All types derive from the type object
class Test
{
    static void Main() {
        int i = 123;
        object o = i;        // boxing
        int j = (int) o;    // unboxing
        Console.WriteLine(3.ToString());
    }
}