J/Direct is an application programming interface (API) from Microsoft that allows applications written in the Java programming language to make programming requests for Windows operating system services. Introduced in June 1997, J/Direct allows Java applications to make calls on Windows dynamic link libraries (DLLs). The existing DLLs do not need to be changed manually, because J/Direct automatically converts many commonly-used data types, according to Microsoft. Unlike earlier Java-to-Windows tools, J/Direct eliminates the need for programmers to write wrapper code around existing Windows applications.
J/Direct supports Microsoft's Windows 32-bit APIs and has been included in the software developer's kit (SDK) for Internet Explorer.