Improve error messages when creating tasks

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@274659 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/ComponentHelper.java

@@ -465,6 +465,10 @@ public class ComponentHelper  {
             String msg = "   +Task: " + taskType;
             project.log (msg, Project.MSG_DEBUG);
             return task;
+        } catch (NoClassDefFoundError ncdfe) {
+            String msg = "Task " + taskType + ": A class needed by class "
+                + c + " cannot be found: " + ncdfe.getMessage();
+            throw new BuildException(msg, ncdfe);
         } catch (Throwable t) {
             System.out.println("task CL=" + c.getClassLoader());
             String msg = "Could not create task of type: "

src/main/org/apache/tools/ant/taskdefs/Definer.java

@@ -250,7 +250,7 @@ public abstract class Definer extends Task {
                 + " cannot be found";
             throw new BuildException(msg, cnfe, getLocation());
         } catch (NoClassDefFoundError ncdfe) {
-            String msg = getTaskName() + "A class needed on loading by class "
+            String msg = getTaskName() + ": A class needed by class "
                 + value + " cannot be found: " + ncdfe.getMessage();
             throw new BuildException(msg, ncdfe, location);
         }