Sadiq786

Java vs. .Net
Bent Thomsen
bt@cs.auc.dk
Department of Computer Science
Aalborg University

A typical .NET Enterprise Solution

IIS on W2k Server
Browser

Windows
Client

ASP
.NET

.NET
managed
component

SQL
Server

A typical J2EE Enterprise Solution

Java App
Server
Servlet
EJB
JSP

Browser

Java
Client

DB
Server

Java vs .Net Solutions

– Both multi-tiered, similar computing technologies
– Both support “standards”
– Both offer different tools & ways to achieve the same
goal.
– A lot of parallelism can be seen.
– Very difficult to compare and qualify the comparison
because each has its own advantages &
disadvantages.

The TMC Petshop Performance Case Study
•

Java Pet Store is Sun’s primary blueprint application for J2EE
–
–
–

•

The .NET Petshop is a port of the J2EE Java Pet Store to .NET
–
–
–

•

Source: http://java.sun.com/j2ee/blueprints
Illustrates best coding practices for J2EE
Ships as a sample application in IBM Websphere, Oracle Application
Server 9i, Sun iPlanet, and
BEA WebLogic
Source: http://www.gotdotnet.com/compare
Implements the same functionality as Java Pet Store
Illustrates best coding practices for .NET Framework

In the TMC Petshop Performance Case Study, The Middleware
Company implemented both the Java Pet Store and the .Net
Petshop.
–
–

The J2EE version ran on two different application servers
All versions used the same hardware and OS

Java Pet Store Components
– The Storefront presents the main user interface in a
Web front-end. Customers use the Storefront to place
orders for pets.
– The Order Processing Center (OPC) receives orders
from the Storefront.
– The Supplier fulfills orders from the OPC from
inventory and invoices the OPC.
– The Admin presents the administrator interface in a
JFC/Swing front-end. Administrators use the Admin
to examine pending orders and approve or deny them.

Java Pet Store vs. .Net Pet Shop

Porting Java Pet Store to .NET
15500

14,273

Lines of Code Required

14000

.NET Petshop
11500

Java Pet Store

9000

7500

5,891

5,404

4,410
5000
2,865

2,566
710

2500

Total Lines
of Code

User
Interface

Middle Tier

761

412

74

Data Tier Configuration

How Microsoft interprets the data
–
–
–

Based on Oracle-published data for tuned version of Java Pet Store
Using Oracle’s test scripts from their “9i App Server Challenge”
Run on equivalent hardware

Supporting 6 times more users
Response Time (Seconds)

1.0
0.8
0.6

2800% Better performance
0.4
0.2
0

0

500

1000
1500
2000
User Load Level

2500

2750

The “Conclusions”
• Microsoft concludes: ".NET is 28 times faster than J2EE"
–
–
–
–

Because:
“Java PetShop” is Sun’s “best practice” example
Numbers compared with published Oracle results
Identical functionality, all code published and documented

• Can we believe the raw numbers? Yes!
– Why? Microsoft delivers full docs on the entire scenario

• But 28 times really?

The Shootout afterwards
• Java PetShop: J2EE blueprint application
– Built by Sun to show "best practice" design
– Implementation by TMC missed quite a few optimizations

• .NET PetShop
– Built by TMC (with help from MS) with different design
• Plain classes instead of container managed components
• Middle tier moved into ASP.NET
• Using stored procedures instead of ad-hoc SQL
• Uses server-side caching of ASP.NET
• Many performance optimizations applied

• Most Java devotees find this highly unfair

TMC revisits the Pet Shop
• Re-implementation of J2EE version
– 17 times performance increase
– Second version showed some J2EE implementation equal .Net
– Second version is a testimony to performance tuning

What does the comparison tell us?
•
•
•
•

It is very difficult to make such comparisons
That .Net has gained maturity extremely fast
That the two frameworks are very similar
The Devil is in the detail

So let’s look at some details

Comparing the stacks

…

…

Enterprise solutions

Phoenix, Tiles, Java Faces

ASP.Net

JSP

C#

Base Class Library

J2EE Class Library
Java runtime

Win32

J2EE App Servers
Websphere, Weblogic, Tomcat, etc.

MSMQ, COM+, IIS,
WMI, AD, ADAM,
Indexing, UDDI, etc.

JMS

Apache

Win32, Unix, Linux

BEA Weblogic

C++

JDBC

CLR

VB

ADO.NET

Java

Servlets

Webshpere Studio

Visual Studio.net

Struts

Eclipse

Perl

Extensions:

P&P blocks

Python

Third party extensions

Java vs. C#
–
–
–
–

C# is an object oriented language of the C++/Java flavor
Syntax similar to Java and C/C++.
Quite an impressive design and care for details
Java developers will feel comfortable
• most of the time and frustrated when things are different
– MS says: “C# combines the power of VC++ with the ease of
usage of VB”
• Not really true:
– C# is really powerful BUT
– It is not easy to learn for non C++/Java programmers
– It is the language to learn if you are serious about .NET!

Java vs. C#
// This is a comment in Java code
class HelloWorld{
public static void main(String[] args){
for(int i= 1; i<= 100; i++)
System.out.println("Hello!");
}
}
// This is a comment in C#
using System;
class HelloWorld{
static void Main(){
for(int i=1; i<=100; i++)
Console.WriteLine("Hello");
}
}
}

Primitives
• Java
–
–
–
–

int, float, double, etc.
Allocated on stack
Not an Object
Not extensible

// C#
struct Point
{
int x;
int y;
Point(int x, int y)
{
this.x = x;
this.y = y;
}
}

• C#
–
–
–
–
–
–

int, float, double, etc.
structs
Allocated on stack
Inherited from object class
structs can implement interfaces
Cannot inherit from another
class

Classes – Overriding Methods
• Java
– All methods are implicitly
virtual

• C#
– Explicitly use ‘virtual’ and
‘override’ keywords

class B
{
public void foo() { }
}

class B
{
public virtual void foo() { }
}

class D extends B
{
public void foo() { }
}

class D:B
{
public override void foo() { }
}

// D’s foo() overrides B’s foo()

// D’s foo() overrides B’s foo()

Exceptions
• Java
– C++-style try/catch blocks
– finally– action done even after
an exception is caught
– throws – methods identify what
exceptions they throw

• C#
– C++-style try/catch blocks
– finally – same as Java
– Does not support throws clause

// Java – throws an IOException
public void myFunc(int a) throws IOException
{
// Work…
}

// Java and C#
try {
// Stuff…
}
catch {
// Ack!
}
finally {
// Always!
}

Java vs. C# in High-performance computations

C# Features not in Java
•
•
•
•
•
•
•
•
•

No automatic fall-through from one case block to the next
Strongly-typed enums
By reference calls are explicit at caller AND callee
Method overrides are explicit
Supports versioning
Structs (value types)
Integrated support for properties and events
Can still use pointers with RAD language
Can share data and use functionality with components written
in many different languages

CLR vs JVM
C#

VB
.Net

Managed Lots of other
C/C++
Languages

Java

MSIL

Byte Codes

CLR
CTS GC Security
Runtime Services

JRE (JVM)
GC Security
Runtime Services

Windows OS

Mac

Win Unix Linux

Both are ‘middle layers’ between an intermediate
language & the underlying OS

.Net on other platforms
•

ECMA standardisation
– ECMA 334 and 335

•

The Mono Project
–
–
–
–

•

Shared Source Common Language Runtime
CLI, C# and Jscript
FreeBSD and Windows implementations
Linux port underway

DOT GNU project
– Portable .Net implementation
– C# for both CIL and JVM

JVM vs. CLR
– JVM designed for platform independence
• Single language: Java (?)
• A separate JVM for each OS & device
– CLR designed for language independence
• Multiple languages for development
– C++, VB, C#, (J#)
– APL, COBOL, Eiffel, Forth, Fortran, Haskel, SML, Mercury,
Mondrian, Oberon, Pascal, Perl, Python, RPG, Scheme, SmallScript, …
– Impressive usage of formal methods and programming language
research during development
– Impressive extensions for generics and support for functional languages
underway
• Underlying OS: Windows (?)

Java Byte Code and MSIL
•
•
•

Java byte code (or JVML) is the low-level language of the JVM.
MSIL (or CIL or IL) is the low-level language of the .NET Common
Language Runtime (CLR).
Superficially, the two languages look very similar.
JVML:

•
•

MSIL:
iload 1
iload 2
iadd
istore 3

ldloc.1
ldloc.2
add
stloc.3

One difference is that MSIL is designed only for JIT compilation.
The generic add instruction would require an interpreter to track the
data type of the top of stack element, which would be prohibitively
expensive.

JVM vs. CLR at a glance
JVM

CLR

Managed execution
environment

X

X

Garbage Collection

X

X

Metadata and
Bytecode

X

X

Platformabstraction class
library

X

X

Runtime-level
security

X

X

Runs across
hardware platforms

X

?

J2EE 1.5
• J2EE (1.5) preview of 26.4.2004
– Focus on ease of development
• Generics and metadata as in J2SE 1.5 (more like C#)
• Java Studio Creator tool (in beta from April 2004) (more
like Visual Studio .Net)
– Timeframe
• To be discussed at JavaOne in June
• Finalized in approximately one year
– IBM push for truly open source Java
– Others hesitate (even Open Source JBoss)

What about mobile?
• Web Services are fine as n-tier applications with UI
provided through browser, but …
• On mobile devices WAP hasn’t really caught on
• Even iMode hasn’t caught on in Europe
• Renewed Thin/Thick client discussion
• Java applications on Mobile devices are reasonably
successful
• Now Microsoft is moving fast into the field with .Net
Compact Framework

Two Devices

Nokia 6600

Orange SPV E200

Building Mobile Solutions is harder
• Mobile device
– Software infrastructure, hardware requirements

• Communication technology
– On-/Offline scenario
– Wireless Wide Area Networks/ Wireless Local Area Networks
– Communication protocol

• Application architecture scenario
– Thin/fat client

• Data management
– Synchronisation
– On-/offline capabilities

• Security issues
– Dangers for mobile devices
– Threats of communication technology
– Danger of exposing enterprise data

Therefore ...
The Java vs. Net discussion goes mobile
• Java 2 Micro Edition (J2ME) is not ONE Java edition
• An J2ME compliant application consists of
–
–
–
–

Configuration
Profile (e.g. Personal, Mobile Information Device Profile (MIDP))
Application code
Vendor specific UI

• 3 Contenders to compare
– Java 2 Micro Edition – Connected Device Configuration (CDC)
– Java 2 Micro Edition – Connected Limited Device Configuration
(CLDC)
– Microsoft .NET Compact Framework

Student Project
• Group of Master Level Students (Hovedfag)
–
–
–
–

Bjørn D. Rasmussen
Casper S. Jensen
Jimmy Nielsen
Lasse Jensen

• Collaboration with DEIF
• Project Goals
– Build end-to-end mobile client, wireless, webservices based
application with back-end interface to SCADA
– In Java (J2ME/J2EE) and in .Net
– Compare the two solutions on a set of criteria

Basis of comparison
Objective measurements
• Lines of code
• Development tools
• Documentation
• Infrastructure
• Performance
• Architectural pattern
• Security
• Price
• Development time

Subjective measurements
• Developer satisfaction
• End-user satisfaction

DEIF M-Vision
(SCADA up and running in 30 minutes)

Development tools and Documentation
• Server-side is well supported by both Java and .NET IDEs
• On the client-side .NET IDEs benefit from the fact that .NET CF
is so close to .NET (With Java there are separate IDEs for
desktop and mobile application development)
• Compatibility problems between Java vendors
• Java IDEs are slow!
• C# is a richer/more complex language than Java
• Both Java and .NET have well documented API
• Web service documentation
– .NET - MSDN
– Java – Google

• Support for encryption of web services
– .Net CF: HTTPS and SOAP extensions
– J2ME: HTTPS, but only in CDC & MIDP 2.0

Performance
• Server-side web service performance study with:
– Microsoft Application Server (v. 5.1)
– Sun ONE Application Server (v. 7.0)

• Tested for:
– Throughput
– Failure rate
– Average response time

Performance – Average response time

Development time
• Slow start-up when developing in Java
– Jungle of web service implementations
– IDE incompatibility problems
• Emulators
• kSOAP

• Trouble-free implementation in .NET

Subjective Measures
• Developer satisfaction
– VS.NET integrates web service and mobile application
development far better than any Java IDE
– A subset of an API is a better solution for mobile devices
instead of an entirely new API

• End-user satisfaction
– DEIF would choose a .NET based solution since startup time
is very important
– DEIF only needs a limited number of IDE licenses
– Extra price for a SmartPhone 2003 is insignificant compared
to the value it gives
– The SmartPhone 2003 is more ”fancy” than the Java phones

Students Conclusions
• We see .NET as a better designed framework because:
– it eliminates the language barrier while also being platform
independent
– it makes only little distinction between desktop and mobile
application development
• Sun’s application server performance is very poor compared to
IIS.
• License fees for a Java based solution are cheaper but .NET might
catch up when considering development time
• We tried a combined .NET and Java solution but this has shown
to be very troublesome!

My conclusions
• The two worlds are becoming more and more similar
– But it seems that you have to work harder in Java than in .Net
– .Net is currently driving technology transfer from Research to
Product

• Windows generation at University now
• Watch-out in the mobile world
• Vodafone to offer Microsoft Smart phones
– http://msmobiles.com/news.php/2504.html
– Fed-up with Nokia promoting own brand, rather than operator
brand

What do these comparisons tell us?
•
•
•
•

It is very difficult to make such comparisons
That .Net has gained maturity extremely fast
That the two frameworks are very similar
You will not be sacked for choosing the right J2EE
application server ;-)
• The Devil is in the detail
–
–
–
–

C# is not Java
ADO.NET is not JDBC
CLR is not JVM
CF.Net smartphones are very different from Java Smartphones

Choosing between Java and .Net
• The ultimate choice usually depends not on
technical superiority, but on:
–
–
–
–

cultural/”religious”/political preferences
Skill set of your developers
Customer preference
Vendor relations

The future of Java and .Net
• The two frameworks are becoming more and more alike
• However:
– .Net is Microsoft’s core strategy
• .Net will be part of OS in the next generation of Windows
• Lot’s of innovation in Longhorn – Avalon, indogo, WinFS
– Is Java in Sun’s core strategy?
• Java 1.5 SE is very close to C# 2.0/.Net CLR
• Sun Java Studio Creator somewhat close to VS.Net
• Some talk of JVM as multi-language platform, but not
really so far …
• Sun in “Java as Open Source” battle with IBM

Sun vs. Microsoft Stock Prices

53

Choosing between Java and .Net
• You are most likely to be developing in both
environments for the foreseeable future
– Gartner Group: 30+% of all enterprise applications will have both J2EE
and .Net code
– Often IIS in front of J2EE infrastructure
– Interoperability issues
• Web Services (often too slow or doesn’t support …)
• J2EE/.Net bridge (IL -> JBC or JBC ->IL)

• Look out for “The third way”
– Linux, Apache, MySQL, PhP, …

• Look out for disruptive technologies
–
–
–
–

It only takes one guy to get the right idea
and a small team to implement a completely new platform
and One large company to productise it
or a lot of grassroots …
54

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