Compile clojure source into class (AOT) from command line (not using lein)

Question

I'm trying to compile clojure source into class file, and run it using command line only, no lein, nor (possibly) reply.

I have core.clj in src/hello directory.

.
└── src
    └── hello
        └── core.clj

This is source code.

(ns hello.core)
(defn -main
  "This should be pretty simple."
  []
  (println "Hello, World!"))

using (compile) in REPL.

From the hint in this site ( http://clojure.org/compilation ), I tried to get class file from REPL.

I started REPL with lein repl in src directory, then tried to compile to get an error.

user=> (compile 'hello.core)

CompilerException java.io.IOException: No such file or directory, compiling:(hello/core.clj:1:1)  

Command line

From this post simple tool for compiling Clojure .clj into .class / .jar and How to compile file in clojure , it seems like that I can compile the clojure source outside REPL.

I tried this in . to get an error.

> java -cp .:<PATH>/clojure-1.6.0.jar -Dclojure.compile.path=build clojure.lang.Compile src/hello/core.clj 
Compiling src/hello/core.clj to build
Exception in thread "main" java.io.FileNotFoundException: Could not locate 
hello/core/clj__init.class or hello/core/clj.clj on classpath: 
at clojure.lang.RT.load(RT.java:443)
at clojure.lang.RT.load(RT.java:411) 
...

So, here are my questions:

• How can I compile the clojure source to get the class with/without REPL?
• How to run the class with Java? Is it enough to execute java -cp .:CLOJURE_JAR main ?

Answer 1

REPL

When invoking REPL, you should add class path.

java -cp .:<PATH>/clojure-1.6.0.jar:./src clojure.main

You need to set the *compile-path* with (set! *compile-path* "build") .

Then you can compile to get the class file.

user=> (compile 'hello.core)
hello.core

Command line

There are two issues:

1. For compilation, the CP should include the source directory.
2. The parameter is not the file path, but the namespace.

This is to invoke the compiler.

clojure> java -cp .:<PATH>/clojure-1.6.0.jar:./src -Dclojure.compile.path=build clojure.lang.Compile hello.core
Compiling hello.core to build

Execution of the class file

You should point to the directory where the class files are located.

clojure> java -cp .:<PATH>/clojure-1.6.0.jar:./build hello.core
Hello, World!

References

• Compiling Clojure?
• http://clojure.org/compilation