diff --git a/java/org/apache/catalina/servlets/DefaultServlet.java b/java/org/apache/catalina/servlets/DefaultServlet.java
index 7d55cf1c3ffc..c9982054eac8 100644
--- a/java/org/apache/catalina/servlets/DefaultServlet.java
+++ b/java/org/apache/catalina/servlets/DefaultServlet.java
@@ -2183,7 +2183,7 @@ protected boolean checkIfModifiedSince(HttpServletRequest request, HttpServletRe
         }
 
         long resourceLastModified = resource.getLastModified();
-        if (resourceLastModified <= -1) {
+        if (resourceLastModified <= 0) {
             // MUST ignore if the resource does not have a modification date available.
             return true;
         }
@@ -2315,7 +2315,7 @@ protected boolean checkIfUnmodifiedSince(HttpServletRequest request, HttpServlet
             WebResource resource) throws IOException {
 
         long resourceLastModified = resource.getLastModified();
-        if (resourceLastModified <= -1) {
+        if (resourceLastModified <= 0) {
             // MUST ignore if the resource does not have a modification date available.
             return true;
         }