Return value from getLastModified is not truncated to seconds

[rodcheater]

Consider this servlet:

package org.acme

import jakarta.servlet.annotation.WebServlet
import jakarta.servlet.http.HttpServlet
import jakarta.servlet.http.HttpServletRequest
import jakarta.servlet.http.HttpServletResponse

@WebServlet(urlPatterns = ["/test"])
class TestServlet : HttpServlet() {
    override fun doGet(req: HttpServletRequest, resp: HttpServletResponse) {
        resp.contentType = "text/plain"
        resp.writer.write("Hello")
    }

    override fun getLastModified(req: HttpServletRequest): Long {
        return 1750746812123
    }
}

Run up an application with this servlet then follow these steps:

1. Run curl -v http://localhost:8080/test.
2. Observe that the response includes the header Last-Modified: Tue, 24 Jun 2025 06:33:32 GMT.
3. Run curl -v http://localhost:8080/test -H 'If-Modified-Since: Tue, 24 Jun 2025 06:33:32 GMT'.

Expected result:

A 304 not modified response is returned.

Actual result:

A 200 response is returned.

If you then modify the servlet to return 1750746812000 from getLastModified then the last curl command returns the 304 as expected.

Compare your implementation to Tomcat’s for example; they truncate the value returned by getLastModified to the second before comparing it with the If-Modified-Since timestamp because that’s the precision of HTTP dates.