OCA 8 e-book: String replace contradiction?

[Chris Kuyler]

Hi there,

I'm planning to take the OCA 8 exam in a few months and I've already downloaded the OCA 8 ebook from O'Reilly to prepare for it.

One thing I'm still unsure of. On page 110 it gives the following examples for the String replace function:

System.out.println("abcabc".replace('a', 'A')); // AbcAbc
System.out.println("abcabc".replace("a", "A")); // AbcAbc

So this would seemingly demonstrate that for the replace method, all occurrences are replaced (i.e. both a's are capitalized after the operation).

However, on page 111 there is the following example:

String lowercase = trimmed.toLowerCase(); // "animal"
String result = lowercase.replace('a', 'A'); // "Animal"

So in this case, only the first letter a is replaced, and not the second one. Am I missing something here, or is there a typo somewhere?

Thanks in advance!

Chris

[Roel De Nijs]

Hi Chris,

First of all, a warm welcome to CodeRanch!

Chris Kuyler wrote:Am I missing something here, or is there a typo somewhere?

Let's see what the javadoc of String.replace tells us:

replace(char oldChar, char newChar) wrote:Returns a string resulting from replacing all occurrences of oldChar in this string with newChar.

And this code definitely shows it's a typo on page 111:

String result = lowercase.replace('a', 'A');
System.out.println(result); // prints AnimAl

Hope it helps!
Kind regards,
Roel

[Paul Clapham]

Chris Kuyler wrote:On page 110 it gives the following examples for the String replace function

What you are missing is that you think that there are two examples for one method there. (By the way the Java name is "method", not "function".) But there are two different methods in that example. The first method takes two char values as its parameters and the second method takes two String values as its parameters. And the two methods work differently; have a look in the API document to read about how they actually work.

[Roel De Nijs]

Paul Clapham wrote:And the two methods work differently; have a look in the API document to read about how they actually work.

Both methods will replace all occurences according to javadoc:

replace(char oldChar, char newChar) wrote:Returns a string resulting from replacing all occurrences of oldChar in this string with newChar.

replace(CharSequence target, CharSequence replacement) wrote:Replaces each substring of this string that matches the literal target sequence with the specified literal replacement sequence. The replacement proceeds from the beginning of the string to the end, for example, replacing "aa" with "b" in the string "aaa" will result in "ba" rather than "ab".

And illustrated in this little code snippet as well:

String result1 = lowercase.replace('a', 'A');
String result2 = lowercase.replace("a", "A");
System.out.println(result1 + " - " + result2); // prints AnimAl - AnimAl

Kind regards,
Roel

[Jeanne Boyarsky]

Chris,
Welcome to CodeRanch! Thank you for pointing out the errata. Until the publisher starts their errata page, I'm keeping a list here. I want to congratulate you for being the first person I don't know in the real word who found/posted an error. (The other two are from Scott and one of my friends.)

ps - It's interesting that it is possible to download an e-book published by Wiley on O'Reilly given that they are competing publishing houses.

[Scott Selikoff]

Thanks Chris! We really do appreciate it. The book goes through a lot of revisions and sometimes errors creep in late, sometimes even after Jeanne and I have signed off on something. These things happen and were glad we have thoughtful readers to help find these mistakes. Keep up the good work!

[Chris Kuyler]

Thanks for the clarification everyone, and for the welcome!

Jeanne, I appreciate you having given this topic credit on your errata page. I'm surprised no one noticed on the forum yet, but I guess most of those going for OCA 8 are waiting for the printed version (or even still just opting for OCA 7). The reason I chose the e-book was because I liked being able to study from anywhere, without having to carry a big book around.

I'll of course be happy to post again if I notice something else.

[Roel De Nijs]

Chris Kuyler wrote:I'm surprised no one noticed on the forum yet, but I guess most of those going for OCA 8 are waiting for the printed version (or even still just opting for OCA 7).

People who want to take on OCP certification after passing OCA don't have another option then OCA 7, because the OCP 8 beta isn't announced yet. And after the beta ends, you'll have to wait another 11 weeks before you know your score. And you can't combine different version certifications. So I think currently the OCA 7 is still the more popular one.

[Chris Kuyler]

Roel De Nijs wrote:

Chris Kuyler wrote:I'm surprised no one noticed on the forum yet, but I guess most of those going for OCA 8 are waiting for the printed version (or even still just opting for OCA 7).

People who want to take on OCP certification after passing OCA don't have another option then OCA 7, because the OCP 8 beta isn't announced yet. And after the beta ends, you'll have to wait another 11 weeks before you know your score. And you can't combine different version certifications. So I think currently the OCA 7 is still the more popular one.

Yeah I guess that makes sense. I want to get OCA certified within a few months. I don't mind waiting another few months after that for the OCP 8.

[Chris Kuyler]

Jeanne Boyarsky wrote:Until the publisher starts their errata page, I'm keeping a list here. I want to congratulate you for being the first person I don't know in the real word who found/posted an error. (The other two are from Scott and one of my friends.)

I may have another small typo for your list. A stray L on page 124:

for (int i = 0; i < numbers.length; i++)
L System.out.print (numbers[i] + " ");

[Jeanne Boyarsky]

Chris Kuyler wrote:I may have another small typo for your list. A stray L on page 124:

Thanks. Added it to the list as well. This one is interesting. It was right when I first wrote it. Then I must have hit the L key when replying to comments from the editor. And then there it was.