Use existing function for checking object is array

Author: romainbrenguier

src/goto-programs/builtin_functions.cpp

@@ -31,6 +31,7 @@ Author: Daniel Kroening, [email protected]
 
 #include <util/c_types.h>
 #include <ansi-c/string_constant.h>
+#include <java_bytecode/java_types.h>
 
 #include "format_strings.h"
 
@@ -627,7 +628,7 @@ void goto_convertt::do_java_new_array(
   t_n->source_location=location;
 
   const struct_typet &struct_type=to_struct_type(ns.follow(object_type));
-  PRECONDITION(struct_type.components().size() == 3);
+  PRECONDITION(is_valid_java_array(struct_type));
 
   // Init base class:
   dereference_exprt deref(lhs, object_type);