diff --git a/javadoc/plugin.jelly b/javadoc/plugin.jelly
index f4db98ca..c08bafa5 100644
--- a/javadoc/plugin.jelly
+++ b/javadoc/plugin.jelly
@@ -109,7 +109,7 @@ internal_javadoc_working_dir      = [${internal_javadoc_working_dir}]
         <j:set var="internal_javadoc_needed" scope="parent" value="false" />
         
         <!-- test if sourceModifications are defined -->
-        <j:if test="${not empty(pom.build.sourceModifications)}">
+        <j:if test="${pom.build.sourceModifications!=null and !pom.build.sourceModifications.isEmpty()}">
           <j:if test="${maven.javadoc.debug}"><ant:echo>sourceModifications used.</ant:echo></j:if>
           <util:tokenize var="sources_dirs" delim="${path.separator}">${context.getAntProject().getReferences().get('maven.compile.src.set')}</util:tokenize>
           <ant:copy todir="${internal_javadoc_src_tmp}">
@@ -137,7 +137,7 @@ internal_javadoc_working_dir      = [${internal_javadoc_working_dir}]
           </ant:path>
         </j:if>
         <!-- test if sourceModifications aren't defined -->
-        <j:if test="${empty(pom.build.sourceModifications)}">
+        <j:if test="${pom.build.sourceModifications==null || pom.build.sourceModifications.isEmpty()}">
           <j:if test="${maven.javadoc.debug}"><ant:echo>sourceModifications not used.</ant:echo></j:if>
           <ant:path id="internal_javadoc_sources">
             <ant:pathelement path="${context.getAntProject().getReferences().get('maven.compile.src.set')}"/>