diff --git a/WHATSNEW b/WHATSNEW
index affa69769..f76fae1eb 100644
--- a/WHATSNEW
+++ b/WHATSNEW
@@ -73,6 +73,9 @@ Fixed bugs:
    within messageLogged while a different thread also accessed one.
    Bugzilla report 45194
 
+ * Handle null result of system getProperty() in CommandlineJava.
+   Similar to Bugzilla report 42334.
+
 Other changes:
 --------------
 
diff --git a/src/main/org/apache/tools/ant/types/CommandlineJava.java b/src/main/org/apache/tools/ant/types/CommandlineJava.java
index efaa6f437..921eebd81 100644
--- a/src/main/org/apache/tools/ant/types/CommandlineJava.java
+++ b/src/main/org/apache/tools/ant/types/CommandlineJava.java
@@ -140,7 +140,10 @@ public class CommandlineJava implements Cloneable {
                 Properties p = new Properties();
                 for (Enumeration e = sys.propertyNames(); e.hasMoreElements();) {
                     String name = (String) e.nextElement();
-                    p.put(name, sys.getProperty(name));
+                    String value = sys.getProperty(name);
+                    if (name != null && value != null) {
+                        p.put(name, value);
+                    }
                 }
                 p.putAll(mergePropertySets());
                 for (Enumeration e = variables.elements(); e.hasMoreElements();) {