check for null in Java 11
diff --git a/src/main/java/org/apache/maven/shared/utils/xml/Xpp3DomUtils.java b/src/main/java/org/apache/maven/shared/utils/xml/Xpp3DomUtils.java
index c95f314..c04f619 100644
--- a/src/main/java/org/apache/maven/shared/utils/xml/Xpp3DomUtils.java
+++ b/src/main/java/org/apache/maven/shared/utils/xml/Xpp3DomUtils.java
@@ -148,8 +148,8 @@
     }
 
     /**
-     * @deprecated use <code>String.isBlank()</code> (Java 11+) 
-     *             or <code>org.apache.commons.lang3.StringUtils.isBlank()</code>
+     * @deprecated use <code>org.apache.commons.lang3.StringUtils.isBlank()</code>
+     *     or <code>str == null || String.isBlank(str)</code> (Java 11+)  
      * @param str the string to be checked
      * @return <code>true</code> if the string is null, empty, or whitespace only; <code>false</code> otherwise
      */