# Book Excerpt and Interview: Effective Java, Second Edition

| by Ryan Slobojan 0 Followers on May 13, 2008. Estimated reading time: 1 minute |

Effective Java, Second Edition by Joshua Bloch is an updated version of the classic first edition, which was the winner of a 2001 Jolt Award. This edition has been updated to discuss Java 6 language features, and the back cover of the book describes some of the new topics covered as:

• New coverage of generics, enums, annotations, autoboxing, the for-each loop, varargs, concurrency utilities, and much more
• Updated techniques and best practices on classic topics, including objects, classes, libraries, methods, and serialization
• How to avoid the traps and pitfalls of commonly misunderstood subtleties of the language
• Focus on the language and its most fundamental libraries: java.lang, java.util, and, to a lesser extent, java.util.concurrent and java.io

The book's publisher, Addison-Wesley, made an excerpt available to InfoQ which includes the contents of the fifth chapter, entitled 'Generics'.

From the article:

InfoQ: Are there major changes between the previous version of 'Effective Java' and this one, or is it more of a refinement of existing ideas?

Joshua Bloch: It's a combination of additions and refinements. The second edition covers all the new language features. It has a chapter on generics, one on enums and annotations, and items on the for-each loop, autoboxing, varargs, and static import. The concurrency chapter has been thoroughly revised in light of java.util.concurrent. And all the existing items have been revised to reflect these new features, and to reflect seven more years of experience with the platform.

That said, I worked very hard not to alter the feel of the book. Hopefully it will feel like an old friend to readers of the first edition -- a little wiser and little heavier (21 items and 83 pages, to be precise), but an old friend.

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Great news

Josh,

We all love you and you are the star!!!!!

Thanks
Prashant

what comment ?

which comment were you referring to ?

BR,
~A

Re: what comment ?

My apologies - the comment being referred to is now found at the bottom of the article. When it was moved, the line you mentioned was not updated - it has been fixed now.

Thanks for catching that!

Probable small error on sample chapter

I'm very excited about this edition, and it is great to see InfoQ offering the generics chapter so we can take a peek before the book begins to ship. I don't know if this is the version that went to press, but I think there is a small error on a code snippet. On the bottom of page 121 we find:
// Reduction without generics or concurrency flawstatic Object reduce(List list, Function f, Object initVal) {    Object[] snapshot = list.toArray(); // Locks list internally    Object result = initVal;    for (Object o : list)        result = f.apply(result, o);    return result;}

But I believe the inner loop should have been:
// Reduction without generics or concurrency flawstatic Object reduce(List list, Function f, Object initVal) {    Object[] snapshot = list.toArray(); // Locks list internally    Object result = initVal;    for (Object o : snapshot)        result = f.apply(result, o);    return result;}

Re: Probable small error on sample chapter

I am not sure I agree with your change entirely since the index of the array is never referenced in your code from within the for-each loop. However, I can see what you mean by the book version being incorrect since snapshot is not used anywhere.

Re: Probable small error on sample chapter

Rafael,

You are absolutely right. What's worse, I caught this problem before the book went to print. I fixed it in the code example bundle (which will soon be posted on the book's web site). Somehow I failed to propagate the change into the book. I hope this is the only place where I did this.

I will fix the problem in the second printing and put it on the (currently nonexistent) errata page as soon as possible.

Thanks for spotting this!

Josh

Re: Probable small error on sample chapter

Josh,I'm wondering if you have revised Item 7 in the first edition, which contains this statement (in bold no less), which seems to me to be false:"There is simply no way to extend an instantiable class and add an aspect while preserving the equals contract."The example in the book missed these possible implementations for Point and ColorPoint respectively, which appear to me to fill the bill:  public boolean equals(Object o) {    if (this == o) return true;    if (o == null) return false;    if (o.getClass() != getClass()) return false;    Point p = (Point) o;    return p.x == x && p.y == y;  }  public boolean equals(Object o) {    if (!super.equals(o)) return false;    ColorPoint p = (ColorPoint) o;    return p.color == color;  }

Good Book

Very interesting & useful book. I really liked it

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