How can I use a Scala singleton object in Java?

问题:

I have a Scala object that I need to use in a Java class.

Here's the Scala object

object Person {
  val MALE = "m"
  val FEMALE = "f"
}

How can I use this Scala object in Java?

I have tried the following so far without success (compile errors):

• Person.MALE() //returns a String which is useless as I want the actual Person object

回答1:

Use Person$.MODULE$. See also

• How can I pass a Scala object reference around in Java?
• Singletons as Synthetic classes in Scala?

---

Edit: A working example (I checked, it compiles and works): Scala:

object Person {
  val MALE = "m";
}

Java counterpart:

public class Test {
    Person$ myvar = Person$.MODULE$;

    public static void main(String argv[]) {
        System.out.println(new Test().myvar.MALE());
    }
}

回答2:

In case you use a package object, the access is a bit different

Scala:

package my.scala.package

package object Person {
  val MALE = "m";
}

Java counterpart:

public static void main() {
  System.out.println(my.scala.package.Person.package$.MODULE$.MALE);
}