1.2 and Reserved Words 绪Keyword 论关键字 KeyWord 或保留字 ReservedWord全部小写是 Java语言本身 使用的系统标识符，有特定的语法含义，不能用作标识符使用。
Java所有数据类型的长度都固定，并与平台无关，因此没有sizeof保 留字。 Keywords are special reserved words in Java that you cannot use as identifiers (names) for classes, methods, or variables. They have meaning to the compiler; it uses them to figure out what your source code is trying to do. Table 1-1 contains all 49 of the reserved keywords.
Java Programming, spring, 2012