private static void requireNull(final Object value) {
        if (value != null) {
            throw new IllegalStateException("Attempt to overwrite field that has been assigned. Value: " + value);
        }
    }
<p>Information to be logged in the access log.</p>

<p>This class contains the union of all information that can be
logged with all the supported access log formats.</p>

<p>The add methods can be called multiple times,
but the parameters should be different for each
invocation of the same method.</p>

This class is thread-safe.

@author Tony Vaagenes
@author bakksjo
@author bjorncs
container-core/src/main/java/com/yahoo/container/logging/AccessLogEntry.java