JPA with Toplink Essentials Error Code: 17002

From this post, I am going to start to post solution for different problems or errors in java technologies which i face during development so that others also could get help from my research and don't waste time on that now.

Error is given below:

Exception [TOPLINK-4002] (Oracle TopLink Essentials - 2.1 (Build b52-fcs (09/24/2008))):
oracle.toplink.essentials.exceptions.DatabaseException
Internal Exception: java.sql.SQLException: Io exception:
Invalid number format for port number
Error Code: 17002

Cause Was: I just copied url from a web site and then pasted to persistence. Probably it appended some hidden characters due to which provider game an error about port format. I just rewrite the port number again and error resolved.

Second Error which i faced was:

Exception [TOPLINK-4002] (Oracle TopLink Essentials - 2.1 (Build b52-fcs (09/24/2008))):
oracle.toplink.essentials.exceptions.DatabaseException
Internal Exception: java.sql.SQLException:
Io exception: The Network Adapter could not establish the connection
Error Code: 17002

Cause Was: wrong port number, ip address or network disconnection