




The function java-array-element-type returns the element type of object if object is a Java array:
:array.java.lang.Object, result is :object.java.lang.String, result is :string.t.
If object is some other type of Java object, java-array-element-type returns nil. Otherwise it signals an error.
java-array-element-type is designed to be fast, so it can be used as a predicate to test whether a Java object is an array, and also to check whether some specific operations are applicable to it.LispWorks User Guide and Reference Manual - 20 Sep 2017