Which version of Java does Mac OS X include?
Mac OS X Leopard comes with J2SE 5.0 preinstalled, based on JDK 1.5.0_13_b05. A 32-bit client and 64-bit server VM are available. Mac OS X Leopard also includes JDK 1.4.2_13 which is deprecated. JDK 1.5 is strongly recommended for the best performance, compatibility, and customer exposure. For information on earlier releases of Java on Mac OS X, please see the Java Version Strings section of Technical Note TN2110.