You can not do that. Microflows can not be converted to Java. Mendix interpret the model it does not convert it.
Besides being possible or not, that is exactly what you should not do with Mendix. Its like buying lego blocks making granulate out of it and then using that as material to start building a house.
I guess the idea is to use the Mendix LowCode/NoCode Editor with all of it’s benefit to produce code that can run without any license. It should be obvious why there is no converter that can export a mendix project to java.
In theory you could do this, and this is one of the arguments of why Mendix doesn't suffer from vendor lock-in. This is even specifically called out as a use case of the SDK!
In practice, however, I would say this is very difficult: it requires a deep understanding of three languages: TypeScript (to program your scripts which use the SDK), Java (your target language) and Mendix (your source language).
The high level approach to convert a microflow to Java code is fairly straightforward: