diff --git a/java/plugin.jelly b/java/plugin.jelly
index 7475f300..668b160f 100644
--- a/java/plugin.jelly
+++ b/java/plugin.jelly
@@ -43,6 +43,18 @@
     <ant:echo>Compiling to ${maven.build.dest}</ant:echo>
     <j:choose>
       <j:when test="${sourcesPresent == 'true'}">
+
+        <j:if test="${context.getVariable('maven.compile.target') == null}">
+          <ant:echo>
+==========================================================
+
+  NOTE: Targetting JVM ${java.specification.version}, classes
+  will not run on earlier JVMs
+
+==========================================================
+          </ant:echo>
+        </j:if>
+
       	<ant:javac
           destdir="${maven.build.dest}"
           excludes="**/package.html"