Comparison of the Java and .NET platforms

Traditional computer applications

Desktop applications

 

Although Java's AWT (Abstract Windowing Toolkit) and Swing libraries are not shy of features, Java has struggled to establish a foothold in the desktop market. Sun Microsystems has also been slow, in the eyes of some, to promote Java to developers and end users alike in a way which makes it an appealing choice for desktop software. Even technologies such as Java Web Start, which have few parallels within rival languages and platforms, have barely been promoted. 

The release of Java version 6.0 on December 11, 2006, saw a renewed focus on the desktop market with an extensive set of new tools for closer integration with the desktop. At the 2007 JavaOne conference Sun made further desktop related announcements, including a new language aimed at taking on Adobe Flash (JavaFX), a new lightweight way of downloading the JRE which sees the initial footprint reduced to under 2Mb, and a renewed focus on multimedia libraries.

An alternative to AWT and Swing is the Standard Widget Toolkit (SWT), which was originally developed by IBM and now maintained by the Eclipse Foundation. It attempts to achieve improved performance and visualization of Java desktop applications by relying on underlying native libraries where possible.

On Windows, Microsoft's .NET is popular desktop development providing both Windows Forms (a lightweight wrapper around the Win32 API), Windows Presentation Foundation, and Silverlight. With the integration of .NET into the Windows platform, .NET apps are first class citizens in the Windows environment with tighter OS integration and native look and feel compared to Java's Swing. Outside of Windows, Silverlight is portable to the Mac OSX desktop. Mono is also becoming more common in open source and free software systems due to its inclusion on many Linux desktop environments.

Server applications

 

This is probably the arena in which the two platforms are closest to being considered rivals. Java, through its Java EE (a.k.a. Java Platform Enterprise Edition) platform, and .NET through ASP.NET, compete to create web-based dynamic content and applications.

Both platforms are well used and supported in this market, with a bevy of tools and supporting products available for Java EE and .NET. High-end, large-scale, heavy duty solutions tend to opt for Java EE due to higher stability, scalability, and greater availability of senior developers. For example, for Java: Oracle included direct support for Java into its database, while Google has used Java to power tools like Gmail.

Some of Sun's current Java-related license agreements for Java EE define aspects of the Java platform as a trade secret, and prohibit the end user from contributing to a third-party Java environment. Specifically, at least one current license for a Sun Java EE development package contains the following terms:  

"You may make a single archival copy of Software, but otherwise may not copy, modify, or distribute Software." — "Unless enforcement is prohibited by applicable law, you may not decompile, or reverse engineer Software." — "You may not publish or provide the results of any benchmark or comparison tests run on Software to any third party without the prior written consent of Sun." — "Software is confidential and copyrighted." 

However, while Sun's software is subject to the above license terms, Sun's Java EE API reference has been implemented under an open source license by the JBoss and JOnAS projects.Microsoft's implementation of ASP.NET is not part of the standardized CLI, and while Microsoft's runtime environment and development tools are not subject to comparable secrecy agreements to Java EE, the official Microsoft tools are not open source or free software, and require Windows servers. However, a cross-platform free software ASP.NET 2.0 implementation is part of the Mono project (minus webparts and Web Services Enhancements).