I've got a subtle problem: if I create a byte array, store it in a java.util.ArrayList, and then retrieve the stored byte array, what I get back is not quite the same type as the original byte array. I think that everything is the same, except that the JavaObjects have different values for the intendedClass field. Here is an example: (setq array1 (jnew-array "byte" 1)) (setq array2 (let ((array-list (jnew (jconstructor "java.util.ArrayList")))) ;; put the byte array into the ArrayList (jcall (jmethod "java.util.AbstractList" "add" "java.lang.Object") array-list array1) ;; and pull it back out (jcall (jmethod "java.util.AbstractList" "get" "int") array-list 0))) (describe array1) ;#<jarray [B@c4ff22 {4A44DD}> is an object of type JAVA-OBJECT. ;The wrapped Java object is an array of bytes with 1 element.; No value (describe array2) ;#<jarray [B@c4ff22 {5E6B62}> is an object of type JAVA-OBJECT. ;The wrapped Java object is an array of bytes with 1 element.; No value At this point array1 and array2 look pretty compatible, but ... (sys::%make-byte-array-input-stream array1) ; works fine, gives a #S(SYSTEM::SYSTEM-STREAM) (sys::%make-byte-array-input-stream array2) ; gives a TYPE-ERROR, with message "java.lang.Object is not assignable to [B" The TYPE-ERROR comes from JavaObject.javaInstance(Class<?> c) (line 248 of JavaObject.java). It seems that array1 has intendedClass="[B", and array2 has intendedClass="java.lang.Object", so I'm pretty sure that's my problem. Is there a way to specify the intendedClass of array2? Thanks, -david k.