Version 7 is a new release of the full Java client version. Below are links related to security

Java 7 – Security Features in this new release
http://blogs.pcmag.com/securitywatch/2011/07/java_7_upgrades_security.php
http://www.oracle.com/us/corporate/press/444374

QUOTE: All of the new features and improvements to existing features are cryptography-related and generally related to support for SSL/TLS in the JSSE (Java Secure Socket Extension) APIs. Certification path processing, which is generally SSL/TLS-related anyway, has been strengthened. Finally, a native provider has been added with several Elliptic Curve Cryptography (ECC) algorithms has been added.

Java 7 – Detailed Security Features
http://download.oracle.com/javase/7/docs/technotes/guides/security/enhancements7.html