jnew-runtime-classを参考にしました。
(in-package :jvm)
(defun make-empty-class-file (class-name &optional (super-name "java.lang.Object"))
(make-class-file (make-jvm-class-name class-name)
(make-jvm-class-name super-name)
'(:public)))
(defun create-class-bytes (class-file)
(let ((stream (sys::%make-byte-array-output-stream)))
(write-class-file class-file stream)
(finish-output stream)
(sys::%get-output-stream-bytes stream)))
(defun write-class-bytes (fname bytes)
(with-open-file (f fname :direction :output :element-type '(unsigned-byte 8))
(let ((n (java:jarray-length bytes)))
(dotimes (i n)
(write-byte (mod (java:jarray-ref bytes i) 256) f)))))
(defun create-helloworld-class (class-name fname)
(let ((class-file (make-empty-class-file class-name)))
(let* ((string-array-class (class-array (make-jvm-class-name "java.lang.String")))
(method (make-jvm-method "main" :void `(,string-array-class) :flags '(:public :static))))
(class-add-method class-file method)
(with-code-to-method (class-file method)
(emit-getstatic "java.lang.System" "out" (make-jvm-class-name "java.io.PrintStream"))
(emit 'ldc (pool-string "Hello,World"))
(emit-invokevirtual "java.io.PrintStream"
"println"
`(,(make-jvm-class-name "java.lang.String"))
:void)
(emit 'return))
(finalize-class-file class-file)
(write-class-bytes fname (create-class-bytes class-file)))))
(create-helloworld-class "AbclHelloWorld" "AbclHelloWorld.class")
> java AbclHelloWorld
Hello,World