Enterprise JavaBeans 3.1, 6th Edition

Colophon

The animals on the cover of Enterprise JavaBeans 3.1, Sixth Edition, are a wallaby and her joey. Wallabies are medium-sized marsupials belonging to the kangaroo family (Macropodidae; the second-largest marsupial family). They are grazers and browsers, native to Australia, and found in a variety of habitats on that continent. Female wallabies have a well-developed anterior pouch in which they hold their young. When they are born, the tiny, still-blind joeys instinctively crawl up into their mothers’ pouches and begin to nurse. They stay in the pouch until they are fairly well grown. A female wallaby can support joeys from up to three litters at once: one in her uterus, one in her pouch, and one that has graduated from the pouch but still returns to nurse.

Like all Macropodidae, wallabies have long, narrow hind feet and powerful hind limbs. Their long, heavy tails are used primarily for balance and stability and are not prehensile. Wallabies resemble kangaroos but are smaller: they measure from less than two feet to over five feet long, with the tail accounting for nearly half of their total length. Oddly enough, although they can hop along quite quickly (reaching speeds of up to 50 kilometers per hour), it is physically impossible for wallabies to walk backward!

The three main types of wallaby are brush, rock, and nail-tailed. There are eleven species of brush wallaby (genus Macropus) and six named species of rock wallaby (Petrogale). Brush wallabies usually live in brushland ...