Isn't it written in Java? Why would it need to do that?

IDA has had watermarks and all sorts of other fancy stuff. The real challenge with IDA was extending the demo to allow it to save databases before they started publishing a working older free version.

I like IDA a lot more than I like all the other tools, especially since I consider the user experience and hotkeys far superior, but the other day I did look at something where the disassembly and decompilation was great compared to other tools(one of the r2+ghidra UIs). I think because flirt signatures were missing and I can't get Hexrays to sell me a new license.

Even better, the NSA provides the sources which you can compile yourself:

https://github.com/NationalSecurityAgency/ghidra/releases

It's open source and written in Java.

And if anyone is curious, Java byte code is very easy to decompile and it will come up quite close to the real thing (unless obfuscated)