Question

The following code throws an exception, which I didn’t expect at all!

        long now = System.currentTimeMillis();
        java.sql.Time t1 = new java.sql.Time(now);
        String s1 = new XStream().toXML(t1);
        java.sql.Time t2 = (java.sql.Time) new XStream().fromXML(s1);
        if(!t1.equals(t2)) throw new IllegalArgumentException();

See XStream

The question is, why, and is it a bug in XStream?

Answer 1

A quick Google search gives that XStream uses this class to serialize java.sql.Time:
http://x-stream.github.io/javadoc/com/thoughtworks/xstream/converters/extended/SqlTimeConverter.html

Note the warning:

Converts a java.sql.Time to text.
Warning: Any granularity smaller than seconds is lost.

So it’s being truncated to an even second, and thus the comparison with the original (which has milliseconds) fails.