There is a particular kind of Java code that makes everyone in the code review go silent.
It starts innocently:
Function<Integer, Function<Integer, Function<Integer, Integer>>> add = a -> b -> c -> a + b + c;
Then somebody proudly says:
“Look. Currying.”
And technically, they are correct.
Java can do currying.
Java can also do partial application.
Java can compose functions.
Java can make higher-order functions.
The more interesting question is not whether Java can do it.
It is:
When does currying actually make Java code better?
Because the answer is surprisingly uncomfortable.
In a language designed around ordinary methods, nominal types, overloaded functions, object-oriented APIs, and a type system without first-class function syntax, currying often creates more ceremony than leverage.
