diff --git a/src/main/org/apache/tools/ant/taskdefs/Definer.java b/src/main/org/apache/tools/ant/taskdefs/Definer.java
index c829138a4..67f519d9b 100644
--- a/src/main/org/apache/tools/ant/taskdefs/Definer.java
+++ b/src/main/org/apache/tools/ant/taskdefs/Definer.java
@@ -541,7 +541,7 @@ public abstract class Definer extends Task {
                     + " cannot be found";
                 throw new BuildException(msg, cnfe, getLocation());
             } catch (NoClassDefFoundError ncdfe) {
-                String msg = getTaskName() + "A class needed by class "
+                String msg = getTaskName() + " A class needed by class "
                     + classname + " cannot be found: " + ncdfe.getMessage();
                 throw new BuildException(msg, ncdfe, location);
             }