Apple's latest Java update requires you periodically enable the Java plug-in manually. Here is how this works in OS X.

Although Java initially was hailed in the mid-1990s as a way to run client-side applets, the platform instead became known for its server-side capabilities.

“The Java 7u21 release introduces changes to security messages related to running Java applets and applications,” Oracle said in a technical document that explains the changes.

The security patches, issued by Oracle, correct Java vulnerabilities that have lingered in Web browsers.

A Java update for Mac OS X 10.6 and 10.7 sets Java applets to not run automatically on all browsers, expanding a feature that was first introduced to Safari in April.

For now, businesses that rely on Java browser plugins can continue using them in compatible browsers. But Oracle has a white paper with details about migrating from Java Applets to plugin-free ...