diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index 4d4105d07..3568e1090 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -74,6 +74,7 @@ Harish Prabandham
 Haroon Rafique
 Hiroaki Nakamura
 Holger Engels
+Ignacio Coloma
 Ingenonsya France
 Ingmar Stein
 Irene Rusman
diff --git a/WHATSNEW b/WHATSNEW
index f43dede82..7a94eca26 100644
--- a/WHATSNEW
+++ b/WHATSNEW
@@ -92,6 +92,9 @@ Other changes:
 * Added isSigned condition and task, and signedselector selector
   Bugzilla report 32126.
 
+* Added preserveLastModified attribute to signjar task.
+  Bugzilla report 30987.
+
 Changes from Ant 1.6.2 to current Ant 1.6 CVS version
 =====================================================
 
diff --git a/docs/manual/CoreTasks/signjar.html b/docs/manual/CoreTasks/signjar.html
index ac40facb3..a77c1b51d 100644
--- a/docs/manual/CoreTasks/signjar.html
+++ b/docs/manual/CoreTasks/signjar.html
@@ -92,6 +92,12 @@ block</td>
                      style of standard java memory specs (e.g. 128m = 128 MBytes)</td>
     <td valign="top" align="center">No</td>
   </tr>
+  <tr>
+    <td valign="top">preservelastmodified</td>
+    <td valign="top">Give the signed file the same last modified
+      time as the original jar file.</td>
+    <td valign="top" align="center">No; default false.</td>
+  </tr>
 </table>
 <h3>Parameters as nested elements</h3>
 <table border="1" cellpadding="2" cellspacing="0">
diff --git a/src/etc/testcases/taskdefs/signjar.xml b/src/etc/testcases/taskdefs/signjar.xml
index 14e870760..8ac1d080c 100644
--- a/src/etc/testcases/taskdefs/signjar.xml
+++ b/src/etc/testcases/taskdefs/signjar.xml
@@ -32,6 +32,32 @@
              storepass="apacheant" maxmemory="128m"/>
   </target>
 
+  <target name="preserveLastModified">
+    <jar jarfile="signtest.jar" basedir="${classes.dir}" includes="**/Task.class"/>
+    <touch file="signtest.jar" datetime="06/28/2000 2:02 pm"/>
+    <signjar jar="signtest.jar" alias="testonly" keystore="testkeystore" storepass="apacheant" 
+    	preservelastmodified="true"/>
+    <!-- Currently there is no condition for testing the date of file - so
+         use a selector -->
+    <pathconvert property="signtest.jar.prop" targetos="unix">
+      <path>
+        <fileset dir="." includes="signtest.jar">
+          <date datetime="06/28/2000 2:02 pm" when="equal"/>
+        </fileset>
+      </path>
+      <mapper>
+        <flattenmapper/>
+      </mapper>
+    </pathconvert>
+    <fail message="preserveLastModified did not preserve the last modified time">
+      <condition>
+        <not>
+          <equals arg1="signtest.jar" arg2="signtest.jar"/>
+        </not>
+      </condition>
+    </fail>
+  </target>
+
   <target name="clean">
     <delete file="signtest.jar"/>
   </target>
diff --git a/src/main/org/apache/tools/ant/taskdefs/SignJar.java b/src/main/org/apache/tools/ant/taskdefs/SignJar.java
index cd19b03f0..7e7662c17 100644
--- a/src/main/org/apache/tools/ant/taskdefs/SignJar.java
+++ b/src/main/org/apache/tools/ant/taskdefs/SignJar.java
@@ -66,6 +66,7 @@ public class SignJar extends Task {
     protected boolean verbose;
     protected boolean internalsf;
     protected boolean sectionsonly;
+    protected boolean preserveLastModified;
 
     /** The maximum amount of memory to use for Jar signer */
     private String maxMemory;
@@ -237,6 +238,7 @@ public class SignJar extends Task {
             return;
         }
 
+        long lastModified = jarSource.lastModified();
         final ExecTask cmd = (ExecTask) getProject().createTask("exec");
         cmd.setExecutable(JavaEnvUtils.getJdkExecutable("jarsigner"));
 
@@ -302,6 +304,15 @@ public class SignJar extends Task {
         cmd.setFailonerror(true);
         cmd.setTaskName(getTaskName());
         cmd.execute();
+
+        // restore the lastModified attribute
+        if (preserveLastModified) {
+            if (jarTarget != null) {
+                jarTarget.setLastModified(lastModified);
+            } else {
+                jarSource.setLastModified(lastModified);
+            }
+        }
     }
 
     protected boolean isUpToDate(File jarFile, File signedjarFile) {
@@ -345,5 +356,14 @@ public class SignJar extends Task {
             return false;
         }
     }
+
+    /**
+     * true to indicate that the signed jar modification date remains the same as the original.
+     * Defaults to false
+     * @param preserveLastModified if true preserve the last modified time
+     */
+    public void setPreserveLastModified(boolean preserveLastModified) {
+        this.preserveLastModified = preserveLastModified;
+    }
 }
 
diff --git a/src/testcases/org/apache/tools/ant/taskdefs/SignJarTest.java b/src/testcases/org/apache/tools/ant/taskdefs/SignJarTest.java
index 8f946edcb..7921b84bb 100644
--- a/src/testcases/org/apache/tools/ant/taskdefs/SignJarTest.java
+++ b/src/testcases/org/apache/tools/ant/taskdefs/SignJarTest.java
@@ -66,4 +66,8 @@ public class SignJarTest extends BuildFileTest {
     public void testURLKeystoreHTTP() {
         executeTarget("urlKeystoreHTTP");
     }
+
+    public void testPreserveLastModified() {
+        executeTarget("preserveLastModified");
+    }
 }