Everyone knows that Mac is safer than Windows because almost all malicious software targets Windows. But every rule has exceptions, and in this case, the exception has been Java.
Java is unusual in that any company can write a Java runtime environment for any operating system. Microsoft, at one point, provided one for Windows, but those days are long gone. ThinkPad laptops still come with a Java runtime developed by IBM. Netscape used to ship its own Java runtime as part of the Navigator Web browser. Today, most Windows users get their Java runtime from Sun Microsystems, the company that originally developed the language.
For whatever reason, Sun does not provide a Java runtime for Macs, instead this is left to Apple.* And, Apple has a history of being slow to fix bugs in Java, trailing Sun by many months.
Mac users can go to my Javatester.org Web site to see the version of Java being used by their web browser. Anyone using multiple web browsers needs to check the Java version in each browser separately.
Apple supports three versions/editions/families of Java:
The oldest family is 1.4.2 and the latest version there is now 1.4.2_18. (The prior buggy version was 1.4.2_16.)
Next is the 1.5.0 family where the latest go-round is 1.5.0_16. (The prior buggy version was 1.5.0_13.)
The latest and greatest version of Java for Macs is 1.6.0 and the latest version here is 1.6.0_07. (The prior buggy version was 1.6.0_05.)