- Java is slow in performance (both on server-side and rich client) as compared to .NET.
- Selection Sort algorithm implementation : .NET performs faster by 2:1 as compared to Java.
- Memory comparison: .NET is using more than twice the amount of memory Java uses to store the same amount of data – 19.9 MB versus a whopping 47.8. Since .NET treats native types – such as double – as objects, that this incurs additional overhead of some form. Java, on the other hand, does not treat native types as objects and therefore can save on this overhead. However, when it comes to real-world object allocation, it appears that .NET is more efficient.
- Conclusion: Thus, as we have seen, .NET 2.0 won 2 out of the 3 major tests – clearly besting Java 1.5 in both execution speed and real-world memory efficiency. Java did, however, manage to hold its own in the native types memory comparison by a pretty wide margin. This indicates that on the whole .NET is a more efficient platform, with perhaps at least one area for improvement – native type memory efficiency.
- The Java Swing UI looks and feels ugly.
- There are too many options in Java to choose from (like Swing/SWT for UI development, Struts/Tapestry/Velocity etc for Web framework, Spring/EJB/xWorks for business tier, IDEA/Netbeans/Eclipse for IDE) and this requires developers to learn more than one way of doing the same thing.
The reason there are many more Java frameworks out there is simply because Java has been around longer, enough to have several good frameworks mature and spread. Many of those are being ported to .NET and others will rise up.
- You can only program in Java whereas .NET supports multiple languages to run on its CLR.
In short, .NET has managed to surpass Java VM in performance and the cost involved in procuring the tools for development in .NET is not a factor against MS .NET (as investing in the tools for development is only 20% of the total cost of development). But ...
- Java is portable and you can run it on Unix servers (Unix remains the server of choice for production deployments in most cases).
- Java EE has matured over time and has more developer mind-share (about 4 million Java developers as in 2004).
- There is alot of investment in Java today and many big companies like Sun, IBM, BEA, Oracle has vested interest (tools, AS, support & services) in not letting the technology go to dust.
- Sun's open sourcing Java SE (under GPLv2) will enable JDK to be bundled with major Linux distros which in the past have not been able to do so due to licensing issues.
- There are more than 200 models of mobile phones which run Java and several wireless providers across the world provide Java content to such Java enabled phones. On the contrary there are only 10 or so Windows mobile phones today (this i read from some site i cannot find out now).
.NET had many missing parts that the Java world has filled in its years of existence, but these are being filled and completed even as we speak. Moreover, these are usually fixed in ways compatible with the original Java implementations - moving from JUnit to NUnit or from Spring to Spring.NET (or the other way around) is probably easier than from totally disparate implementations.
In some areas, .NET is still lagging behind. COM+ is the only application server I know of that can run .NET components, and it's often overkill. A more flexible solution for that in the .NET world would be great. The .NET solution biosphere is still not as mature as Java, but what it does, it does very well - often better than the original Java product.
- J2ME royalty earned (by Sun) per Java mobile phone sold (less than $1) remains a cash cow for Sun to date.
- Also Sun sells certifications to Java EE application server vendors for their compliance to the Java EE Specs.
- Sun also makes money by selling books, certifications and trainings for Java technology.
- Sun provides consulting services for Java enterprise application development.
- Sun also sells its hardware (server boxes) together with Solaris OS for deployment of Java enterprise applications in production.
An interesting article with more statistics concludes that Java is loosing ground to LAMP and .NET for web application development. More and more corporations have adopted .NET since its easier and faster to program in than Java. .NET is gaining on developer mind share too.
I don't know how credible are the stats presented in the articles (i have found on the web and linked to above) or whether someone is funding a malicious propaganda against Java as i donot see how anything can beat free (free IDE, even AS, and you pay for a short-term support and you go live with Java). Of course, PHP has gained ground for building small websites and applications but when the applications are big then Java holds good steed. In my opinion, Java and .NET are both competent platforms for developing enterprise applications and both have their own pros and cons to be considered when a decision is being made on which platform to develop on. BTW, here are a few comments which i liked (by one Mr. Abdul Habra) refuting the claims made in the business week article:
I do not know where to start, look at these statements:
1. LAMP is used more than Java: a more accurate comparison is to compare LAMP against LAMJ or P against J. Java is used widely with LAM components.
2. PHP is used more than Java: Well, HTML is used more than both. Counting all the sites that use Java or PHP is meaningless. It is given that there are more basic, simple, or home pages than there are professional complex site. Simple sites are more likely to be written in PHP. This is similar to saying there is more printed material in the USA Today than for Shakespeare, hence USA Today must be better.
3. Sales Of AJAX books grew more than Java: The term AJAX did not exist two years ago, so selling 10 books compared with 0 books two years ago means that AJAX sales have grown infinitely. The other flaw in this argument is that many of the AJAX frameworks are Java based. This is like saying the sale of JDBC, JMX, … grew more than Java. Look at http://adaptivepath.com/publications/essays/archives/000385.php for the first public article of AJAX, it is dated Feb 18 2005.
4. Google and Yahoo do not use Java: Both are C++ shops. Their usage of AJAX is with C++/Java at the backend. Remember, Google hired Josh Bloch not for his PHP skills.
5. Merrill Lynch & Co ... using just Linux and the Apache server: So what language do they use? The author does not say. Clearly you cannot write programs with Linux and Apache, you need a programming language. This is a meaningless statement.
6. Jupiter Research report showed that 62% of ... .NET, vs. 36% for IBM's WebSphere: This only shows that .Net is used more than WS. It does not count WL, Tomcat, JBoss, ...
In conclusion, this is not new. I have been seeing this since Java became popular. Most of these claims are made by ignorant people or people with hidden agendas.

