diff --git a/docs/manual/CoreTasks/ear.html b/docs/manual/CoreTasks/ear.html
index dc4a05d44..9b3b0e912 100644
--- a/docs/manual/CoreTasks/ear.html
+++ b/docs/manual/CoreTasks/ear.html
@@ -31,7 +31,7 @@ attributes of zipfilesets in a Zip or Jar task.)</p>
   <tr>
     <td valign="top">appxml</td>
     <td valign="top">The deployment descriptor to use (META-INF/application.xml).</td>
-    <td valign="top" align="center">Yes</td>
+    <td valign="top" align="center">Yes, unless update is set to true</td>
   </tr>
   <tr>
     <td valign="top">basedir</td>
diff --git a/docs/manual/CoreTasks/war.html b/docs/manual/CoreTasks/war.html
index 65e8aedbd..1e29b8b64 100644
--- a/docs/manual/CoreTasks/war.html
+++ b/docs/manual/CoreTasks/war.html
@@ -33,7 +33,7 @@ attributes of zipfilesets in a Zip or Jar task.)</p>
   <tr>
     <td valign="top">webxml</td>
     <td valign="top">The deployment descriptor to use (WEB-INF/web.xml).</td>
-    <td valign="top" align="center">Yes</td>
+    <td valign="top" align="center">Yes, unless update is set to true</td>
   </tr>
   <tr>
     <td valign="top">basedir</td>
diff --git a/src/main/org/apache/tools/ant/taskdefs/Ear.java b/src/main/org/apache/tools/ant/taskdefs/Ear.java
index e9b3d0c1d..bff4f0ab5 100644
--- a/src/main/org/apache/tools/ant/taskdefs/Ear.java
+++ b/src/main/org/apache/tools/ant/taskdefs/Ear.java
@@ -111,7 +111,7 @@ public class Ear extends Jar {
         throws IOException, BuildException
     {
         // If no webxml file is specified, it's an error.
-        if (deploymentDescriptor == null) {
+        if (deploymentDescriptor == null && !isInUpdateMode()) {
             throw new BuildException("appxml attribute is required", location);
         }
         
diff --git a/src/main/org/apache/tools/ant/taskdefs/War.java b/src/main/org/apache/tools/ant/taskdefs/War.java
index 417a805dd..918b36f40 100644
--- a/src/main/org/apache/tools/ant/taskdefs/War.java
+++ b/src/main/org/apache/tools/ant/taskdefs/War.java
@@ -119,7 +119,7 @@ public class War extends Jar {
         throws IOException, BuildException
     {
         // If no webxml file is specified, it's an error.
-        if (deploymentDescriptor == null) {
+        if (deploymentDescriptor == null && !isInUpdateMode()) {
             throw new BuildException("webxml attribute is required", location);
         }
         
diff --git a/src/main/org/apache/tools/ant/taskdefs/Zip.java b/src/main/org/apache/tools/ant/taskdefs/Zip.java
index 8cbc4bb96..050663a33 100644
--- a/src/main/org/apache/tools/ant/taskdefs/Zip.java
+++ b/src/main/org/apache/tools/ant/taskdefs/Zip.java
@@ -76,6 +76,7 @@ import org.apache.tools.ant.types.FileSet;
 import org.apache.tools.ant.types.EnumeratedAttribute;
 import org.apache.tools.ant.types.ZipFileSet;
 import org.apache.tools.ant.types.ZipScanner;
+import org.apache.tools.ant.util.FileUtils;
 import org.apache.tools.ant.util.SourceFileScanner;
 import org.apache.tools.ant.util.MergingMapper;
 import org.apache.tools.zip.ZipOutputStream;
@@ -165,6 +166,13 @@ public class Zip extends MatchingTask {
         doUpdate = c;
     }
 
+    /**
+     * Are we updating an existing archive?
+     */
+    public boolean isInUpdateMode() {
+        return doUpdate;
+    }
+
     /**
      * Adds a set of files (nested fileset attribute).
      */
@@ -228,23 +236,12 @@ public class Zip extends MatchingTask {
         // we don't need to update if the original file doesn't exist
 
         addingNewFiles = true;
-        boolean reallyDoUpdate = false;
-        if (doUpdate && zipFile.exists())
+        doUpdate = doUpdate && zipFile.exists();
+        if (doUpdate)
         {
-            reallyDoUpdate = true;
-
-            int i;
-            for (i=0; i < 1000; i++)
-            {
-                renamedFile = new File(zipFile.getParent(), "tmp."+i);
-
-                if (!renamedFile.exists()) {
-                    break;
-                }
-            }
-            if (i == 1000) {
-                throw new BuildException("Can't find available temporary filename to which to rename old file.");
-            }
+            FileUtils fileUtils = FileUtils.newFileUtils();
+            renamedFile = fileUtils.createTempFile("zip", ".tmp",
+                                                   fileUtils.getParentFile(zipFile));
 
             try
             {
@@ -277,7 +274,7 @@ public class Zip extends MatchingTask {
             return;
         }
 
-        String action = reallyDoUpdate ? "Updating " : "Building ";
+        String action = doUpdate ? "Updating " : "Building ";
 
         log(action + archiveType +": "+ zipFile.getAbsolutePath());
 
@@ -300,7 +297,7 @@ public class Zip extends MatchingTask {
                 }
                 // Add the explicit filesets to the archive.
                 addFiles(filesets, zOut);
-                if (reallyDoUpdate) {
+                if (doUpdate) {
                     addingNewFiles = false;
                     ZipFileSet oldFiles = new ZipFileSet();
                     oldFiles.setSrc(renamedFile);
@@ -345,7 +342,7 @@ public class Zip extends MatchingTask {
                 msg += " (and the archive is probably corrupt but I could not delete it)";
             }
 
-            if (reallyDoUpdate) {
+            if (doUpdate) {
                 if (!renamedFile.renameTo(zipFile)) {
                     msg+=" (and I couldn't rename the temporary file "+
                         renamedFile.getName()+" back)";
@@ -358,7 +355,7 @@ public class Zip extends MatchingTask {
         }
 
         // If we've been successful on an update, delete the temporary file
-        if (success && reallyDoUpdate) {
+        if (success && doUpdate) {
             if (!renamedFile.delete()) {
                 log ("Warning: unable to delete temporary file " +
                      renamedFile.getName(), Project.MSG_WARN);