Return -1 after parse error for Expires header

Issue: SPR-10648

spring-web/src/main/java/org/springframework/http/HttpHeaders.java

@@ -391,12 +391,20 @@ public class HttpHeaders implements MultiValueMap<String, String>, Serializable
 	}
 
 	/**
-	 * Returns the date and time at which the message is no longer valid, as specified by the {@code Expires} header.
+	 * Returns the date and time at which the message is no longer valid, as specified by
-	 * <p>The date is returned as the number of milliseconds since January 1, 1970 GMT. Returns -1 when the date is unknown.
+	 * the {@code Expires} header.
+	 * <p>The date is returned as the number of milliseconds since January 1, 1970 GMT.
+	 * Returns -1 when the date is unknown.
+	 *
 	 * @return the expires value
 	 */
 	public long getExpires() {
-		return getFirstDate(EXPIRES);
+		try {
+			return getFirstDate(EXPIRES);
+		}
+		catch (IllegalArgumentException ex) {
+			return -1;
+		}
 	}
 
 	/**

spring-web/src/test/java/org/springframework/http/HttpHeadersTests.java

@@ -210,6 +210,14 @@ public class HttpHeadersTests {
 		assertEquals("Invalid Expires header", "Thu, 18 Dec 2008 10:20:00 GMT", headers.getFirst("expires"));
 	}
 
+	// SPR-10648 (example is from INT-3063)
+
+	@Test
+	public void expiresInvalidDate() {
+		headers.set("Expires", "-1");
+		assertEquals(-1, headers.getExpires());
+	}
+
 	@Test
 	public void ifModifiedSince() {
 		Calendar calendar = new GregorianCalendar(2008, 11, 18, 11, 20);