convert jms time stamp to current date and time

I need to know when the message has been received thus i'm printing开发者_运维技巧 the jms timestamp i.e msg.getJMSTimestamp() but this returns some number in milliseconds like 1300339215983. I dont undersatnd what value it is. How do i convert it to current standard date and time.

Thanks.

java.util.Date = new java.util.Date(msg.getJMSTimestamp());