Visual J# (pronounced 'jay-sharp') programming language is a discontinued transitional language for programmers of Java and Visual J++ languages, so they may use their existing knowledge and applications on .NET Framework.

In programming, J# can work with Java bytecode as well as source so it can be used to transition applications that use third-party libraries even if their original source code is unavailable. It was developed by the Hyderabad-based Microsoft India Development Center at HITEC City in India.^[1]

Fundamental differences between J# and Java

Java and J# use the same general syntax but there are non-Java conventions in J# to support the .NET environment. For example, to use .NET "properties" with a standard JavaBean class, it is necessary to prefix getXxx and setXxx methods with the Javadoc-like annotation:

        /** @beanproperty        */

...and change the corresponding private variable name to be different from the suffix of the getXxx/setXxx names.

J# does not compile Java-language source code to Java bytecode (.class files), and does not support Java applet development or the ability to host applets directly in a web browser, although it does provide a wrapper called Microsoft J# Browser Controls for hosting them as ActiveX objects. Finally, Java Native Interface (JNI) and Raw Native Interface (RNI) are substituted with P/Invoke; J# does not support Remote Method Invocation (RMI).

J#'s interface to the .NET framework is solid, but not as seamless as C#. In particular, J# code cannot define new .NET attributes, events, value types, or delegates. J# can make use of these language constructs if they are defined in an assembly written in another language, but its inability to define new ones limits J#'s reach and interoperability compared to other .NET languages.

Future of J#

J# is generally not considered to be a language on par with C# or Visual Basic .NET, and does not have the same level of support, samples, or updates as the other languages do.^{[citation needed]} This fact notwithstanding, J# is a usable .NET language and has access to most of the Common Language Runtime (CLR) features.

The Microsoft J# product team made two important announcements on the future of J# in January 2007:^[2]

• That Microsoft would produce an updated version of Visual J# 2.0, including a 64-bit redistributable version, called J# 2.0 Second Edition to meet customer demand for 64-bit runtime support. Microsoft released Visual J# 2.0 Second Edition on 18 May 2007.^[3]
• Retirement of the J# language and Java Language Conversion Assistant from future versions of Visual Studio, since the existing J# feature set largely meets customer needs and usage of J# is declining. The last version shipping with Visual Studio 2005 will be supported until 2015 as per the product life-cycle strategy.
• Calling J# code from .NET 4.0 code will fail unless vjsnativ.dll is pre-loaded.^[4].

A link to download Visual J# 2005 Express Edition is no longer available from Microsoft's website; however, the old link which was previously available is still valid.^[5]

See also

• IKVM.NET – Free implementation of Java for Mono and .NET Framework

References

External links

• Official website
• Visual J# Design Choices An interview with Pratap Lakshman