[REQ] Java generator should be able to use BigDecimal instead of float for "float" number in generated Model classes.

Is your feature request related to a problem? Please describe.

Let's say we have this definition:

  amount:
    type: "number"
    format: "float"
    description: "Amount of money"

Java generator will create model class with property amount of java type Float. This is good for most uses, but it's infamously bad for storing money.

Swagger spec itself is agnostic about how "float" type is implemented - all it means is that it's floating point number with (potentially) unlimited precision (same applies for JSON number type definition).

Describe the solution you'd like

Better option here would be to generate classes with BigDecimal instead which is perfect for money. I expect that this would be opt-in so by default the floats would be generated and only if you configure BigDecimals then these would be used.

Start by locating the Java generator's mapping for OpenAPI number types and its existing configuration options. Add an opt-in BigDecimal path while preserving Float as the default, then verify generated model output for both settings with the generator's relevant tests.