Point Operator to access field

[SackCastellon]

@grouillier

The JVM allows it. Groovy has the Expando class. You can create your own custom class that extends Expando, then you can add fields and properties to existing objects. You can also dynamically modify the class itself so that all future objects have the new fields and properties.

Disclaimer: I’ve never learned or used Groovy.

Having a quick look at the Javadoc of the Expando class I can deduce that what happens in something similar to what Kotlin does with extension functions, that is that the compiler maps each extension function to a static function with an additional argument being the receiver.

So what (I think) the Groovy compiler does is that it maps each property access of a class extending Expando to a getProperty()/setProperty() call, for instance:
expandoClass.lastName = "Smith" gets translated to expandoClass.setProperty("lastName", "Smith")
and
println expandoClass.lastName gets translated to println expandoClass.getProperty("firstName")

This means that the JVM really doesn’t support this feature.