diff --git a/src/main/org/apache/tools/ant/taskdefs/Zip.java b/src/main/org/apache/tools/ant/taskdefs/Zip.java
index 7eacaf239..9caede3fc 100644
--- a/src/main/org/apache/tools/ant/taskdefs/Zip.java
+++ b/src/main/org/apache/tools/ant/taskdefs/Zip.java
@@ -824,9 +824,11 @@ public class Zip extends MatchingTask {
         if (! skipWriting) {
             ZipEntry ze = new ZipEntry (vPath);
             if (dir != null && dir.exists()) {
-                ze.setTime(dir.lastModified());
+                // ZIPs store time with a granularity of 2 seconds, round up
+                ze.setTime(dir.lastModified() + 1999);
             } else {
-                ze.setTime(System.currentTimeMillis());
+                // ZIPs store time with a granularity of 2 seconds, round up
+                ze.setTime(System.currentTimeMillis() + 1999);
             }
             ze.setSize (0);
             ze.setMethod (ZipEntry.STORED);
@@ -957,7 +959,8 @@ public class Zip extends MatchingTask {
 
         FileInputStream fIn = new FileInputStream(file);
         try {
-            zipFile(fIn, zOut, vPath, file.lastModified(), null, mode);
+            // ZIPs store time with a granularity of 2 seconds, round up
+            zipFile(fIn, zOut, vPath, file.lastModified() + 1999, null, mode);
         } finally {
             fIn.close();
         }
diff --git a/src/main/org/apache/tools/zip/ZipOutputStream.java b/src/main/org/apache/tools/zip/ZipOutputStream.java
index 71d4c0c89..bbc22ed63 100644
--- a/src/main/org/apache/tools/zip/ZipOutputStream.java
+++ b/src/main/org/apache/tools/zip/ZipOutputStream.java
@@ -653,7 +653,7 @@ public class ZipOutputStream extends DeflaterOutputStream {
             |         (time.getDate() << 16)
             |         (time.getHours() << 11)
             |         (time.getMinutes() << 5)
-            |         ((time.getSeconds() + 2) >> 1);
+            |         (time.getSeconds() >> 1);
         
         byte[] result = new byte[4];
         result[0] = (byte) ((value & 0xFF));