TimestampmyTimestamp = new Timestamp((new java.util.Date()).getTime());

The best way to store a timestamp in MySQL is to either store it in a timestamp field or in an INT(10) field and insert using UNIX_TIMESTAMP(). Both ways are exactly the same and both use 4 bytes of data.

This is default 0000-00-00 00:00:00 value when we create a timestamp field in mysql database.

Timestamp.

There's no working method available to hide the last seen timestamp on WhatsApp. May be the next WhatsAp update will bring in a feature to do that.