Java vs. C#

Attribute

Java
 
Below Java 5, Java doesn't have such 
feature to mark on the 
class or code to 
indicate its purpose. 
But java has several tools
to help you achieve it.
How Java 5  annotates code 
will be updated soon

C#
 
Attribute is an object that associates with an element in a program.
Attributes: intrinsic and custom.
using System;
class BasicAttributeDemo
{
    [Obsolete]
    public void MyFirstDeprecatedMethod()
    {
        Console.WriteLine("Called MyFirstDeprecatedMethod().");
    }

    [ObsoleteAttribute]
    public void MySecondDeprecatedMethod()
    {
        Console.WriteLine("Called MySecondDeprecatedMethod().");
    }

    [Obsolete("You shouldn't use this method anymore.")]
    public void MyThirdDeprecatedMethod()
    {
        Console.WriteLine("Called MyThirdDeprecatedMethod().");
    }

    // make the program thread safe for COM
    [STAThread]
    static void Main(string[] args)
    {
        BasicAttributeDemo attrDemo = new BasicAttributeDemo();

        attrDemo.MyFirstDeprecatedMethod();
        attrDemo.MySecondDeprecatedMethod();
        attrDemo.MyThirdDeprecatedMethod();
    }
}
>csc BasicAttributeDemo.cs
Microsoft (R) Visual C# .NET Compiler version 7.10.2292.4
for Microsoft (R) .NET Framework version 1.1.4322
Copyright (C) Microsoft Corporation 2001-2002. All rights reserved.

BasicAttributeDemo.cs(29,3): warning CS0612:
'BasicAttributeDemo.MyFirstDeprecatedMethod()' is obsolete
BasicAttributeDemo.cs(30,3): warning CS0612:
'BasicAttributeDemo.MySecondDeprecatedMethod()' is obsolete
BasicAttributeDemo.cs(31,3): warning CS0618:
'BasicAttributeDemo.MyThirdDeprecatedMethod()' is obsolete: 'You
shouldn't use this method anymore.' 


class AttributeParamsDemo
{
    [DllImport("User32.dll", EntryPoint="MessageBox")]
    static extern int MessageDialog(int hWnd, string msg, string caption, int msgType);

    [STAThread]
    static void Main(string[] args)
    {
        MessageDialog(0, "MessageDialog Called!", "DllImport Demo", 0);
    }
}


Attribute Target Can be Applied To 
all         everything 
assembly    entire assembly 
class       classes 
constructor constructors 
delegate    delegates 
enum        enumerations 
event       events 
field       fields 
interface   interfaces 
method      methods 
module      modules (compiled code that can be part of an assembly) 
parameter   parameters 
property    properties 
returnvalue return values 
struct      structures 


using System;

[assembly:CLSCompliant(true)]

public class AttributeTargetDemo
{
    public void NonClsCompliantMethod(uint nclsParam)//line 6
    {
        Console.WriteLine("Called NonClsCompliantMethod().");
    }

    [STAThread]
    static void Main(string[] args)
    {
        uint myUint = 0;

        AttributeTargetDemo tgtDemo = new AttributeTargetDemo();

        tgtDemo.NonClsCompliantMethod(myUint);
    }
}
//it won't compile: 
Either change CLSCompliant to false or 
change uint type to int type at line 6.
int type is CLSCompliant type.