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Comment by kerng | Hacker News Reader

I do remember depending on the site pinvoke.net quite a bit in the past - but yeah this was always possible with C#. It was even what made J++ (Microsoft's Java, before it became C#) unique compared to Sun's version in the 90s, as it allowed this kind of tight Windows integration also if I recall correctly.

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It was also possible in VB6, planet-source-code was the best source for that..

You could even call the win32 api from 16-bit VB3 by going through the wow thunking api. It worked well but the declarations were quite hairy.

yup, you could even have multi-threads, hide inside other processes and run from there and all the C++ fun stuff..

Didn’t JNI allow that kind of integration?

I think it was because MS’ Java’s standard libraries included Java wrappers over Win32 already, so programming beginners in Java can make “real”-looking Windows desktop GUI applications without knowing any C or at least knowing how to read *.h files and translate them to Java.

Microsoft had RNI which was comparable to JNI and could be used to write native code. It also had J/Direct which could be used to bind existing native code to a Java method declared native with only a comment, the closest to that for standard Java that I know of is JNA and apparently that wasn't around until 2007?

JNI is a bit different - you have to write code in C or C++ that wraps native APIs you want to call, in a certain very specific way that then makes it possible to call it via methods declared as "native" in Java.

P/Invoke does not require such a layer - you simply declare enums, structs, and functions from the native API directly in your C# code, and then you can call them.

For those familiar with Python, the Java way is more like writing a Python extension module in C, and the C# way is more like using ctypes (but way faster).

Java has some third party libraries that are basically P/Invoke equivalent; JNA is probably the most used one.

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