better reporting of linkage error in checkTaskClass

PR: 26332
Obtained from: Jesse Glick


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@275955 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -926,6 +926,10 @@ public class Project {
                 + taskClass;
             log(message, Project.MSG_ERR);
             throw new BuildException(message);
+        } catch (LinkageError e) {
+            String message = "Could not load " + taskClass + ": " + e;
+            log(message, Project.MSG_ERR);
+            throw new BuildException(message, e);
         }
         if (!Task.class.isAssignableFrom(taskClass)) {
             TaskAdapter.checkTaskClass(taskClass, this);

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

@@ -1,7 +1,7 @@
 /*
  * The Apache Software License, Version 1.1
  *
- * Copyright (c) 2000-2003 The Apache Software Foundation.  All rights
+ * Copyright (c) 2000-2004 The Apache Software Foundation.  All rights
  * reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -106,6 +106,10 @@ public class TaskAdapter extends Task implements TypeAdapter {
             final String message = "No public execute() in " + taskClass;
             project.log(message, Project.MSG_ERR);
             throw new BuildException(message);
+        } catch (LinkageError e) {
+            String message = "Could not load " + taskClass + ": " + e;
+            project.log(message, Project.MSG_ERR);
+            throw new BuildException(message, e);
         }
     }