Calling a method on a Java class from Clojure

Question

I have this simple Java source:

class HelloJava {
 public static String greetMe() {
 return "Hello, this is Java calling!";
 }
}

which I compile down into a class file called HelloJava.class

HelloWorld.class is in the same directory that I launch the Repl from.

How can I now call HelloJava.greetMe() in the Clojure REPL?

Answer 1

Static methods are accessed via Class/method, and like most things in Clojure, are invoked via wrapping in parens:

(import org.user3231690.HelloJava)
(HelloJava/greetMe)

• Zuriar: Ok, I see. How about if I haven't put the class in a package but have just compiled it into the same directory I launched the Repl from. Shouldn't this also be on the classpath so (import HelloJava) should work?
• Zuriar: OK, I figured it out. I have HelloJava.class in the directory I start the Repl from so I need to do: java -cp clojure-1.6.0.jar:. clojure.main to load the Repl with the current directory in the CP. Now I do (import HelloJava) and it imports. However, when I then do (HelloJava/greetMe) I get IllegalAccessError tried to access class HelloJava from class user$eval3 user/eval3 (NO_SOURCE_FILE:2)
• Zuriar: And the reason for the above IllegalAccessError is because the original Java code did not declare the class as 'public'. It should be public class HelloJava { ....