What is a first class citizen function?

Question

What is a first class citizen function?

Does Java supports first class citizen function?

Edit:
As mention on Wikepedia

F

Answer 1

Functions are first class citizen means you can pass function anywhere as if it's a variable.

From Scala

def isOdd(in: Int) = in % 2 == 1
val n = (1 to 10).toList
n.filter(isOdd)

see here: isOdd is a function. passed as if it's a variale.

Objects are first class citizen in Java. A first class citizen is the one that can be passed anywhere. The parallel is from a first class citizen of country are allowed almost everywhere.

Read:

• When is a feature considered a “First class citizen” in a programming language/platform?
• First-class object
• First-class function