Preface 前前前言言言
The strange history of this book 本本本书书书与与与众众众不不不同同同的的的历历历史史史
In January 1999 I was preparing to teach an introductory programming class in Java. I had
taught it three times and I was getting frustrated. The failure rate in the class was too high
and, even for students who succeeded, the overall level of achievement was too low.
1999年1月，我正准备使用Java教一门编程入门课程。 我之前已经教了三次，并且 感到很沮
丧。 课程的不及格率太高，即使对于及格的学生，整体的收获也太低。
One of the problems I saw was the books. They were too big, with too much unnecessary
detail about Java, and not enough high-level guidance about how to program. And they all
suffered from the trap door effect: they would start out easy, proceed gradually, and then
somewhere around Chapter 5 the bottom would fall out. The students would get too much
new material, too fast, and I would spend the rest of the semester picking up the pieces.
我看到的问题之一是教材。 它们 都太大了，有太多不必要的关于Java的细节， 并且缺乏关
于如何编程的 上层的指导。 同时，它们也缺乏陷阱门效应（trap door effect），即从简单
之处开始 ，并逐渐深入。 因此， 大概到第五章左右，后面的学生开始掉队了。 学生们获得
太多的材料，进展太快，并且我在剩下的学期选择一些片段。
Two weeks before the first day of classes, I decided to write my own book. My goals were:
在开始上课前两周，我决定写一本自己的书。 我的目标是：
• Keep it short. It is better for students to read 10 pages than not read 50 pages.
尽量简短。对于学生，读10页比读50页好。
• Be careful with vocabulary. I tried to minimize the jargon and define each term at
first use.
关注术语表。我试图使用最少的术语并且在第一次使用的时候给出定义。
• Build gradually. To avoid trap doors, I took the most difficult topics and split them
into a series of small steps.
循序渐进。为了避免陷阱门，我将最难的主题拆分成一系列小的步骤。
• Focus on programming, not the programming language. I included the minimum
useful subset of Java and left out the rest.
聚焦于编程，而不是编程语言。我只包括了Java最小的有用的子集， 并且忽略其余
的。
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