UseJava: use CMAKE_COMMAND instead of direct cmake call

Author: dancing-leaves <dancing-leaves@users.noreply.github.com>

Modules/UseJava.cmake

@@ -389,7 +389,7 @@ include(${CMAKE_CURRENT_LIST_DIR}/CMakeParseArguments.cmake)
 function (__java_copy_file src dest comment)
     add_custom_command(
         OUTPUT  ${dest}
-        COMMAND cmake -E copy_if_different
+        COMMAND ${CMAKE_COMMAND} -E copy_if_different
         ARGS    ${src}
                 ${dest}
         DEPENDS ${src}