diff --git a/src/main/org/apache/tools/ant/AntTypeDefinition.java b/src/main/org/apache/tools/ant/AntTypeDefinition.java
index 5a24182da..0e3dd3a34 100644
--- a/src/main/org/apache/tools/ant/AntTypeDefinition.java
+++ b/src/main/org/apache/tools/ant/AntTypeDefinition.java
@@ -329,7 +329,7 @@ public class AntTypeDefinition {
     }
 
     /**
-     * Equality method for this definition
+     * Equality method for this definition (assumes the names are the same)
      *
      * @param other another definition
      * @param project the project the definition
@@ -345,6 +345,69 @@ public class AntTypeDefinition {
         if (!(other.getTypeClass(project).equals(getTypeClass(project)))) {
             return false;
         }
-        return other.getExposedClass(project).equals(getExposedClass(project));
+        if (!other.getExposedClass(project).equals(getExposedClass(project))) {
+            return false;
+        }
+        if (other.adapterClass != adapterClass) {
+            return false;
+        }
+        if (other.adaptToClass != adaptToClass) {
+            return false;
+        }
+        return true;
+    }
+
+    /**
+     * Similar definition
+     * used to compare two definitions defined twice with the same
+     * name and the same types.
+     * the classloader may be different but have the same
+     * path so #sameDefinition cannot
+     * be used.
+     * @param other the definition to compare to
+     * @param project the current project
+     * @return true if the definitions are the same
+     */
+    public boolean similarDefinition(AntTypeDefinition other, Project project) {
+        if (other == null) {
+            return false;
+        }
+        if (getClass() != other.getClass()) {
+            return false;
+        }
+        if (!getClassName().equals(other.getClassName())) {
+            return false;
+        }
+        if (!extractClassname(adapterClass).equals(
+                extractClassname(other.adapterClass))) {
+            return false;
+        }
+        if (!extractClassname(adaptToClass).equals(
+                extractClassname(other.adaptToClass))) {
+            return false;
+        }
+        // all the names are the same: check if the class path of the loader
+        // is the same
+        ClassLoader oldLoader = other.getClassLoader();
+        ClassLoader newLoader = this.getClassLoader();
+        if (oldLoader != null
+            && newLoader != null
+            && oldLoader instanceof AntClassLoader
+            && newLoader instanceof AntClassLoader
+            && ((AntClassLoader) oldLoader).getClasspath()
+            .equals(((AntClassLoader) newLoader).getClasspath())
+            ) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    private String extractClassname(Class c) {
+        if (c == null) {
+            return "<null>";
+        } else {
+            return c.getClass().getName();
+        }
     }
 }
diff --git a/src/main/org/apache/tools/ant/ComponentHelper.java b/src/main/org/apache/tools/ant/ComponentHelper.java
index 3d1837168..5af83be28 100644
--- a/src/main/org/apache/tools/ant/ComponentHelper.java
+++ b/src/main/org/apache/tools/ant/ComponentHelper.java
@@ -670,21 +670,19 @@ public class ComponentHelper  {
                 if (sameDefinition(def, old)) {
                     return;
                 }
+                int logLevel = Project.MSG_WARN;
+                if (def.similarDefinition(old, project)) {
+                    logLevel = Project.MSG_VERBOSE;
+                }
                 Class oldClass = antTypeTable.getExposedClass(name);
-                if (oldClass != null && Task.class.isAssignableFrom(oldClass)) {
-                    int logLevel = Project.MSG_WARN;
-                    if (def.getClassName().equals(old.getClassName())
-                        && def.getClassLoader() == old.getClassLoader()) {
-                        logLevel = Project.MSG_VERBOSE;
-                    }
-                    project.log(
-                        "Trying to override old definition of task "
-                        + name, logLevel);
+                boolean isTask =
+                    (oldClass != null && Task.class.isAssignableFrom(oldClass));
+                project.log(
+                    "Trying to override old definition of "
+                    + (isTask ? "task" : "datatype")
+                    + " " + name, logLevel);
+                if (isTask) {
                     invalidateCreatedTasks(name);
-                } else {
-                    project.log(
-                        "Trying to override old definition of datatype "
-                        + name, Project.MSG_WARN);
                 }
             }
             project.log(" +Datatype " + name + " " + def.getClassName(),
diff --git a/src/main/org/apache/tools/ant/UnknownElement.java b/src/main/org/apache/tools/ant/UnknownElement.java
index b0f69c206..d2854e98f 100644
--- a/src/main/org/apache/tools/ant/UnknownElement.java
+++ b/src/main/org/apache/tools/ant/UnknownElement.java
@@ -530,4 +530,52 @@ public class UnknownElement extends Task {
         }
         return false;
     }
+
+    /**
+     * like contents equals, but ignores project
+     * @param obj the object to check against
+     * @return true if this unknownelement has the same contents the other
+     */
+    public boolean similar(Object obj) {
+        if (obj == null) {
+            return false;
+        }
+        if (!getClass().getName().equals(obj.getClass().getName())) {
+            return false;
+        }
+        UnknownElement other = (UnknownElement) obj;
+        if (!equalsString(elementName, other.elementName)) {
+            return false;
+        }
+        if (!namespace.equals(other.namespace)) {
+            return false;
+        }
+        if (!qname.equals(other.qname)) {
+            return false;
+        }
+        if (!getWrapper().getAttributeMap().equals(
+                other.getWrapper().getAttributeMap())) {
+            return false;
+        }
+        if (children == null) {
+            return other.children == null;
+        }
+        if (children.size() != other.children.size()) {
+            return false;
+        }
+        for (int i = 0; i < children.size(); ++i) {
+            UnknownElement child = (UnknownElement) children.get(i);
+            if (!child.similar(other.children.get(i))) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    private boolean equalsString(String a, String b) {
+        if (a == null) {
+            return b == null;
+        }
+        return a.equals(b);
+    }
 }
diff --git a/src/main/org/apache/tools/ant/taskdefs/DefBase.java b/src/main/org/apache/tools/ant/taskdefs/DefBase.java
index 818317bb0..73c45a600 100644
--- a/src/main/org/apache/tools/ant/taskdefs/DefBase.java
+++ b/src/main/org/apache/tools/ant/taskdefs/DefBase.java
@@ -93,7 +93,7 @@ public abstract class DefBase extends Task implements AntlibInterface {
         if (uri.equals(ProjectHelper.ANT_CORE_URI)) {
             uri = "";
         }
-        if (uri.startsWith("ant:") && !uri.startsWith("antlib:")) {
+        if (uri.startsWith("ant:")) {
             throw new BuildException("Attempt to use a reserved URI " + uri);
         }
         this.uri = uri;
diff --git a/src/main/org/apache/tools/ant/taskdefs/MacroDef.java b/src/main/org/apache/tools/ant/taskdefs/MacroDef.java
index dd5a05d62..0197beb8d 100644
--- a/src/main/org/apache/tools/ant/taskdefs/MacroDef.java
+++ b/src/main/org/apache/tools/ant/taskdefs/MacroDef.java
@@ -102,7 +102,7 @@ public class MacroDef extends Task implements AntlibInterface, TaskContainer {
         if (uri.equals(ProjectHelper.ANT_CORE_URI)) {
             uri = "";
         }
-        if (uri.startsWith("ant:") && !uri.startsWith("antlib:")) {
+        if (uri.startsWith("ant:")) {
             throw new BuildException("Attempt to use a reserved URI " + uri);
         }
         this.uri = uri;
@@ -283,6 +283,7 @@ public class MacroDef extends Task implements AntlibInterface, TaskContainer {
     public static class Attribute {
         private String name;
         private String defaultValue;
+
         /**
          * The name of the attribute.
          *
@@ -319,6 +320,35 @@ public class MacroDef extends Task implements AntlibInterface, TaskContainer {
         public String getDefault() {
             return defaultValue;
         }
+
+        /**
+         * equality method
+         *
+         * @param obj an <code>Object</code> value
+         * @return a <code>boolean</code> value
+         */
+        public boolean equals(Object obj) {
+            if (obj == null) {
+                return false;
+            }
+            if (obj.getClass() != getClass()) {
+                return false;
+            }
+            Attribute other = (Attribute) obj;
+            if (name == null) {
+                return other.name == null;
+            }
+            if (!name.equals(other.name)) {
+                return false;
+            }
+            if (defaultValue == null) {
+                return other.defaultValue == null;
+            }
+            if (!name.equals(other.defaultValue)) {
+                return false;
+            }
+            return true;
+        }
     }
 
     /**
@@ -364,6 +394,74 @@ public class MacroDef extends Task implements AntlibInterface, TaskContainer {
         public boolean isOptional() {
             return optional;
         }
+
+        /**
+         * equality method
+         *
+         * @param obj an <code>Object</code> value
+         * @return a <code>boolean</code> value
+         */
+        public boolean equals(Object obj) {
+            if (obj == null) {
+                return false;
+            }
+            if (obj.getClass() != getClass()) {
+                return false;
+            }
+            TemplateElement other = (TemplateElement) obj;
+            if (name == null) {
+                return other.name == null;
+            }
+            if (!name.equals(other.name)) {
+                return false;
+            }
+            return optional == other.optional;
+        }
+    }
+
+    /**
+     * equality method for macrodef, ignores project and
+     * runtime info.
+     *
+     * @param obj an <code>Object</code> value
+     * @return a <code>boolean</code> value
+     */
+    public boolean equals(Object obj) {
+        if (obj == null) {
+            return false;
+        }
+        if (!obj.getClass().equals(getClass())) {
+            return false;
+        }
+        MacroDef other = (MacroDef) obj;
+        if (name == null) {
+            return other.name == null;
+        }
+        if (!name.equals(other.name)) {
+            return false;
+        }
+        if (uri == null || uri.equals("")
+            || uri.equals(ProjectHelper.ANT_CORE_URI)) {
+            return other.uri == null || other.uri.equals("")
+                || other.uri.equals(ProjectHelper.ANT_CORE_URI);
+        }
+        if (!uri.equals(other.uri)) {
+            return false;
+        }
+
+        if (attributeStyle != other.attributeStyle) {
+            return false;
+        }
+        if (!nestedTask.similar(other.nestedTask)) {
+            return false;
+        }
+        if (!attributes.equals(other.attributes)) {
+            return false;
+        }
+        if (!elements.equals(other.elements)) {
+            return false;
+        }
+        return true;
     }
 
     /**
@@ -372,15 +470,15 @@ public class MacroDef extends Task implements AntlibInterface, TaskContainer {
      * is given.
      */
     private static class MyAntTypeDefinition extends AntTypeDefinition {
-        private MacroDef    template;
+        private MacroDef    macroDef;
 
         /**
          * Creates a new <code>MyAntTypeDefinition</code> instance.
          *
-         * @param template a <code>MacroDef</code> value
+         * @param macroDef a <code>MacroDef</code> value
          */
-        public MyAntTypeDefinition(MacroDef template) {
-            this.template = template;
+        public MyAntTypeDefinition(MacroDef macroDef) {
+            this.macroDef = macroDef;
         }
 
         /**
@@ -394,20 +492,39 @@ public class MacroDef extends Task implements AntlibInterface, TaskContainer {
             if (o == null) {
                 return null;
             }
-            ((MacroInstance) o).setTemplate(template);
+            ((MacroInstance) o).setMacroDef(macroDef);
             return o;
         }
 
         /**
          * Equality method for this definition
-         * This only checks for pointer equality.
          *
          * @param other another definition
          * @param project the current project
          * @return true if the definitions are the same
          */
         public boolean sameDefinition(AntTypeDefinition other, Project project) {
-            return this == other;
+            if (!super.sameDefinition(other, project)) {
+                return false;
+            }
+            MyAntTypeDefinition otherDef = (MyAntTypeDefinition) other;
+            return macroDef.equals(otherDef.macroDef);
+        }
+
+        /**
+         * Similiar method for this definition
+         *
+         * @param other another definition
+         * @param project the current project
+         * @return true if the definitions are the same
+         */
+        public boolean similarDefinition(
+            AntTypeDefinition other, Project project) {
+            if (!super.similarDefinition(other, project)) {
+                return false;
+            }
+            MyAntTypeDefinition otherDef = (MyAntTypeDefinition) other;
+            return macroDef.equals(otherDef.macroDef);
         }
     }
 }
diff --git a/src/main/org/apache/tools/ant/taskdefs/MacroInstance.java b/src/main/org/apache/tools/ant/taskdefs/MacroInstance.java
index 027561e02..856f4c053 100644
--- a/src/main/org/apache/tools/ant/taskdefs/MacroInstance.java
+++ b/src/main/org/apache/tools/ant/taskdefs/MacroInstance.java
@@ -80,7 +80,7 @@ import org.apache.tools.ant.RuntimeConfigurable;
  * @since Ant 1.6
  */
 public class MacroInstance extends Task implements DynamicConfigurator {
-    private MacroDef template;
+    private MacroDef macroDef;
     private Map      map = new HashMap();
     private Map      elements = new HashMap();
     private Hashtable localProperties = new Hashtable();
@@ -88,10 +88,10 @@ public class MacroInstance extends Task implements DynamicConfigurator {
     /**
      * Called from MacroDef.MyAntTypeDefinition#create()
      *
-     * @param template a <code>MacroDef</code> value
+     * @param macroDef a <code>MacroDef</code> value
      */
-    protected void setTemplate(MacroDef template) {
-        this.template = template;
+    protected void setMacroDef(MacroDef macroDef) {
+        this.macroDef = macroDef;
     }
 
     /**
@@ -112,7 +112,7 @@ public class MacroInstance extends Task implements DynamicConfigurator {
      *                        has already been seen
      */
     public Object createDynamicElement(String name) throws BuildException {
-        if (template.getElements().get(name) == null) {
+        if (macroDef.getElements().get(name) == null) {
             throw new BuildException("unsupported element " + name);
         }
         if (elements.get(name) != null) {
@@ -130,7 +130,7 @@ public class MacroInstance extends Task implements DynamicConfigurator {
         private List unknownElements = new ArrayList();
 
         /**
-         * Add an unknown element (to be snipped into the template instance)
+         * Add an unknown element (to be snipped into the macroDef instance)
          *
          * @param nestedTask an unknown element
          */
@@ -225,7 +225,7 @@ public class MacroInstance extends Task implements DynamicConfigurator {
     }
 
     private String macroSubs(String s, Map macroMapping) {
-        if (template.getAttributeStyle() == MacroDef.AttributeStyle.ANT) {
+        if (macroDef.getAttributeStyle() == MacroDef.AttributeStyle.ANT) {
             return macroSubsAnt(s, macroMapping);
         } else {
             return macroSubsXPath(s, macroMapping);
@@ -259,7 +259,7 @@ public class MacroInstance extends Task implements DynamicConfigurator {
             UnknownElement unknownElement = (UnknownElement) r.getProxy();
             String tag = unknownElement.getTag();
             MacroDef.TemplateElement templateElement =
-                (MacroDef.TemplateElement) template.getElements().get(tag);
+                (MacroDef.TemplateElement) macroDef.getElements().get(tag);
             if (templateElement == null) {
                 UnknownElement child = copy(unknownElement);
                 rc.addChild(child.getWrapper());
@@ -294,9 +294,9 @@ public class MacroInstance extends Task implements DynamicConfigurator {
     public void execute() {
         localProperties = new Hashtable();
         Set copyKeys = new HashSet(map.keySet());
-        for (int i = 0; i < template.getAttributes().size(); ++i) {
+        for (int i = 0; i < macroDef.getAttributes().size(); ++i) {
             MacroDef.Attribute attribute =
-                (MacroDef.Attribute) template.getAttributes().get(i);
+                (MacroDef.Attribute) macroDef.getAttributes().get(i);
             String value = (String) map.get(attribute.getName());
             if (value == null) {
                 value = attribute.getDefault();
@@ -315,7 +315,7 @@ public class MacroInstance extends Task implements DynamicConfigurator {
         }
 
         // need to set the project on unknown element
-        UnknownElement c = copy(template.getNestedTask());
+        UnknownElement c = copy(macroDef.getNestedTask());
         c.init();
         c.perform();
     }
diff --git a/src/main/org/apache/tools/ant/taskdefs/PreSetDef.java b/src/main/org/apache/tools/ant/taskdefs/PreSetDef.java
index af57d885c..99c2b40f0 100644
--- a/src/main/org/apache/tools/ant/taskdefs/PreSetDef.java
+++ b/src/main/org/apache/tools/ant/taskdefs/PreSetDef.java
@@ -99,7 +99,7 @@ public class PreSetDef extends Task implements AntlibInterface, TaskContainer {
         if (uri.equals(ProjectHelper.ANT_CORE_URI)) {
             uri = "";
         }
-        if (uri.startsWith("ant:") && !uri.startsWith("antlib:")) {
+        if (uri.startsWith("ant:")) {
             throw new BuildException("Attempt to use a reserved URI " + uri);
         }
         this.uri = uri;
@@ -266,14 +266,51 @@ public class PreSetDef extends Task implements AntlibInterface, TaskContainer {
 
         /**
          * Equality method for this definition
-         * This only checks for pointer equality.
          *
          * @param other another definition
          * @param project the current project
          * @return true if the definitions are the same
          */
         public boolean sameDefinition(AntTypeDefinition other, Project project) {
-            return this == other;
+            if (other == null) {
+                return false;
+            }
+            if (other.getClass() != getClass()) {
+                return false;
+            }
+            MyAntTypeDefinition otherDef = (MyAntTypeDefinition) other;
+            if (!parent.sameDefinition(otherDef.parent, project)) {
+                return false;
+            }
+            if (!element.similar(otherDef.element)) {
+                return false;
+            }
+            return true;
+        }
+
+        /**
+         * Similiar method for this definition
+         *
+         * @param other another definition
+         * @param project the current project
+         * @return true if the definitions are the same
+         */
+        public boolean similarDefinition(
+            AntTypeDefinition other, Project project) {
+            if (other == null) {
+                return false;
+            }
+            if (!other.getClass().getName().equals(getClass().getName())) {
+                return false;
+            }
+            MyAntTypeDefinition otherDef = (MyAntTypeDefinition) other;
+            if (!parent.similarDefinition(otherDef.parent, project)) {
+                return false;
+            }
+            if (!element.similar(otherDef.element)) {
+                return false;
+            }
+            return true;
         }
     }
 }