diff --git a/src/main/org/apache/tools/ant/types/selectors/MappingSelector.java b/src/main/org/apache/tools/ant/types/selectors/MappingSelector.java
index aaba589ea..206cbf4d7 100644
--- a/src/main/org/apache/tools/ant/types/selectors/MappingSelector.java
+++ b/src/main/org/apache/tools/ant/types/selectors/MappingSelector.java
@@ -59,6 +59,7 @@ import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.taskdefs.condition.Os;
 import org.apache.tools.ant.util.IdentityMapper;
 import org.apache.tools.ant.util.FileNameMapper;
+import org.apache.tools.ant.util.FileUtils;
 
 import java.io.File;
 
@@ -78,9 +79,7 @@ public abstract class MappingSelector extends BaseSelector {
      *
      */
     public MappingSelector() {
-        if (Os.isFamily("dos")) {
-            granularity = 2000;
-        }
+        granularity=(int) FileUtils.newFileUtils().getFileTimestampGranularity();
     }
 
 
diff --git a/src/main/org/apache/tools/ant/util/FileUtils.java b/src/main/org/apache/tools/ant/util/FileUtils.java
index ea2f5c3d1..00d8c9477 100644
--- a/src/main/org/apache/tools/ant/util/FileUtils.java
+++ b/src/main/org/apache/tools/ant/util/FileUtils.java
@@ -111,6 +111,11 @@ public class FileUtils {
     private static char[] escapedChar1 = new char[256];
     private static char[] escapedChar2 = new char[256];
 
+    /**
+     * the granularity of timestamps under FAT
+     */
+    public static final long FAT_FILE_TIMESTAMP_GRANULARITY=2000;
+
 
     // stolen from FilePathToURI of the Xerces-J team
     static {
@@ -1328,5 +1333,12 @@ public class FileUtils {
         }
     }
 
+    public long getFileTimestampGranularity() {
+        if(Os.isFamily("dos")) {
+            return FAT_FILE_TIMESTAMP_GRANULARITY;
+        } else {
+            return 0;
+        }
+    }
 }