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Herb Tybur

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since May 12, 2006
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Recent posts by Herb Tybur

Haven't used whizlab's full version but enthuware's is sure a bang for the buck.
Thanks guys!!!

Originally posted by Tiffny Yang:
Congradulation Herb !!! Rock on.

Very helpful information.

Did you do all the 10 Tests in JQPlus?
Did you do the Whizlabs?

What about the the level of difficult of JQPlus compared with real exam?



Yes, I did all the 10 tests and the bonus test. I did not buy whizlab.
It is difficult to say because I thought some of the tests were tougher and some were about the same toughness as the actual exam. I mean there are some questions that are very easy and I didn't get that easy questions in the exam. At the same time, there were some very hard questions too. On an average, I would say it is about the same tilting towards tougher side. The bonus test was quite good because the questions were very similar to the exam questions. But I may be feeling that way because I took it in the end.
14 years ago
I had planned to take the exam two weeks earlier but I received low scores on JQPlus mocks and so I decided to postpone it. Finally, I took the exam yesterday. On the hindsight, I think it was good that postponed it because there were many questions on the exam that I couldn't have answered earlier without further studies.

Thread questions were tricky. One hint: read the API description of the run() method of Thread class. See what happens if you override the run() method and then pass a Runnable to it.

I primarily used K&B book, which is really bulky but necessary. In my last stage if preparation I used Enthuware mock exams and while initially I was skeptical of their free beta version, they are indeed a value for the money. They have a huge database of good questions.

Don't worry too much about the exam format, d&d questions. It's not that hard. They have a sample test that you can take before the start ofthe actual exam (but that sample exam doesn't have any sample on D&D questions, ).
The exam itself is too long though. 72 questions are a bit too much.

Overall, I am just glad that I am through with it. HOlding all the information in my brain hurts
14 years ago
Hi, I need your suggestion on this. I have been following the K&B book and i scored 69% on the included exam. I was quite confident and was going to schedule the exam early next week.
But then I got the enthuware tool and I got only 55% on the first test. I scored low on some of the topics I thought I was good at.

Not sure what to do. Postpone it? What do you think?
Just so you know, this is not on SCJP 5.0 exam.
Looks very impressive but I don't like to depend on alpha or beta versions. When are you planning to release the production version?
Can anybody please give a closure on this? The API for BufferedReader doesn't say anything like that.
Thanks for your information, Edisandro!
I am reading IO stuff and I am seeing that a lot of emphasis is given on File class API and Serialization. Other than that, there is very little to study.
Other than knowing how to chain FileReader and BufferedReader (and their writer counterparts), is there anything else?

Can somebody please tell me what sort of question are asked on this topic?
Just wondering whether java.lang.Math needs to be studied for SCJP 1.5? Some mock exams seem to have questions on it.
The getContent() method should return the same message that was logged. But in the situation that I gave it is giving difference values.

Thread 1 logged "message 1" but it is getting "message 1 message 2" back.


12. Given the scenario: This class is intended to allow users to write a series of messages, so that each message is identified with a timestamp and the name of the thread that wrote the message:

public class Logger {
private StringBuilder contents = new StringBuilder();
public void log(String message) {
contents.append(System.currentTimeMillis());
contents.append(": ");
contents.append(Thread.currentThread().getName());
contents.append(message);
contents.append("\n");
}
public String getContents() { return contents.toString(); }
}


How can we ensure that instances of this class can be safely used by multiple threads?
A. This class is already thread-safe.
B. Replacing StringBuilder with StringBuffer will make this class thread-safe.
C. Synchronize the log() method only.
D. Synchronize the getContents() method only.
E. Synchronize both log() and getContents().
F. This class cannot be made thread-safe.



My answer was F but the correct answer is E. Even if you make both the methods synchronized, the following situation will totally mess the message up:

1. Thread 1 calls log("message");
2. Before thread 2 could do getContent(), thread 2 gets lock and calls log("message2"); This causes the message to contain "message1message2".
3. Thread 1 calls getContent()
4. Thread 2 calls getContent()

Basically, I feel that this class is structurally unsound and cannot be made thread safe.

Am I missing something?
I am not a movie buff but I have a huge ( about 4 gig ) of MP3 and WMAs. All ripped from CDs that I own. The reason I ripped them was to play them right through my computer without worring about changing CDs.

Anyway, I want to store the collection on a DvD (Data DVD and not music DVD) and I would like to know if there is a portable (or mini) dvd player that can play the mp3 and wma files from the DvD.

I have an old mintek dvd player (for regular DVDs) that plays mp3s stored as data files in a data CD but it is not able to play mp3s stored in a DVD.

Any suggestions?
14 years ago

Originally posted by Peer Reynders:


Eh, hybrids are just an (unfortunately necessary) transitional technology.
...
Hydrogen still seems to be the ideal energy carrier.



There is quite a lot of debate on this. Even though hydrogen doesn't cause any pollution while burning, it is not a good fuel at all because it causes more pollution to produce hydrogen (usually through electrolysis, which requires electricity) than when you burn gas.

Hybrid is a very good technology and much better than Hydrogen because it effectivly increases the efficiency of the vehicle by harnessing energy that was being wasted anyway (while braking).

Of course, solar power is the best.
14 years ago
Hi Bert,
Q 2 on page 399.


2. Given two files:
1. class One {
2. public static void main(String[] args) {
3. int assert = 0;
4. }
5. }
Self Test Answers 399
1. class Two {
2. public static void main(String[] args) {
3. assert(false);
4. }
5. }
And the four command-line invocations:
javac -source 1.3 One.java
javac -source 1.4 One.java
javac -source 1.3 Two.java
javac -source 1.4 Two.java



I just wanted to know if it is definitely required to learn 1.5, 1.4, and 1.3 difference.

thanks!!