Jj Roberts

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since Oct 25, 2019
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I dabbled in writing C code for micro controllers for a bit. Around June 2019 I was introduced to Java. I loved it from the start. Now I am studying for the Oracle Certified Professional exams.
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Recent posts by Jj Roberts

I see you tried to format your code. There will be two tags, the opening tag [code=java] and the closing one [/code]. Can you put your code between the opening and closing code tags, please? That will make it easier to read your code   .
2 days ago
Thank you Campbell, I appreciate your tips! I haven't yet really studied IO, but I will definitely look into the classes you brought up. IO is still on my list; right now I am trying to conquer that many-headed monster Modules.
3 days ago
What does your file look like? Is it just one number per line, or is it more complex? Could you post a sample?
3 days ago
You will have to write them into the file as strings to be able to read them. The FileOutputStream is meant to write raw data as it says in the documentation. The docs also say that for writing characters you should consider FileWriter instead.

To convert the integer into a string you could do or a more quick-and-dirty way could be to simply concatenate it with a string, like this:
Here is a small example which does what you want

Notice the try-with-resources which closes the FileWriter automatically.
A note on exception handling: you should always catch the most specific exception that is practical. For example, if your writer throws an IOException, you should catch the IOException, instead of a blanket Exception.

I hope that Helps!
3 days ago
Oh, I was scratching my head over the new title I had never seen before! Being temporarily "promoted" sounds good. What does it actually mean?
3 days ago
Thank you for replying Jeanne and Scott!

Jeanne Boyarsky wrote:I think you got hit by the difference in scope between 1Z0-808 Java 8 OCA) and the 1Z0-815. Oracle added topics to the exam for Java 11. They also moved topics that used to be on the OCP 8 to the OCA 8. This is why it is important to use a study guide for the exam you are taking. i realize that one didn't exist at the time you were studying. You definitely have to know Lists, Set, Map, sort, search and more.

I don't have any previous experience with Java, so this was a case of having no idea of what I should know. I didn't know how serious the test really is, too, so I did not try anything like mock exams, etc   . I know better now! A study guide is key, because you can't tell on your own where the gaps in your knowledge are.

Scott Selikoff wrote:Collections are one of my favorite things in the Java API... whether they are in scope or not, learn them!

Yes, I am definitely going to. I have to write again soon, though, so I need to budget my study time wisely  . Hopefully I can pull everything together to be properly prepared.

Hi! I have been taking both the Enthuware and Whizlabs mock tests in preparation for Oracle's 1z0-815, and I have been wondering: how do the Enthuware practice tests compare with the Whizlabs tests with regard to how hard they are? I have been getting okay scores on the Enthuware tests (71% for foundations, 70% for test 1 and 79% for test 2), but my scores on the Whizlabs tests have been poor (53%, 55%, 59% and 64%) which is a worry for me.

I feel that some of it is because the Whizlabs tests seem to have a lot more sneaky gotchas and also a much bigger emphasis on API methods.

Does anyone have experience with the different mock exams?  Enthuware claims its tests are harder than the real exams, but I’ve heard the Java 11 OCP exams are tougher than earlier ones. How do the different tests compare to each other, and to the real exam? I would like to be able to put my scores in context, so I can determine how ready I am for the real test.

Thank you.
Hi! Another question for Jeanne and Scott

What questions involving Collections and Maps should I expect in the 1z0-815 exam? I expect questions involving Lists, particularly ArrayLists, but I don’t know what level of question to expect. Should I be familiar with all of the List methods?

I (prematurely, see here) attempted the exam before; one of the questions which stumped me involved initialising a field of type Collection with a Map. I thought that was not in scope for this exam, especially as the Oracle prep course I took did not include Maps or Collections. I was wrong. What is in scope for the exam?

Please let me know if this question is too broad or hard to answer. I would just like to know if I’m on the right track to be completely ready for the exam   . Thank you.
You may retake a failed exam, but you may only schedule a retake after 14 days. You may attempt an exam only four times in 12 months.

You can read the Oracle policies here https://education.oracle.com/certification-program-guidelines#2_2
My pleasure! I'm so glad I could help. The apparent inconsistency also confused me at first.
Thank you, it really helps to know what to study. I am finding modules a little tricky, but hopefully I can master them.
Hi all! I am busy studying to take the 1z0-815 Oracle test, so I have a few questions which I am sure Jeanne and Scott are well qualified to answer.

Are jdeps or jar part of the 1z0-815 exam? Jdeps appeared in some of the practise tests I have taken, but I don't know whether to expect questions about them (particularly jdeps) in the exam. I have looked around online, but I haven’t found anything helpful. Neither are in the exam objectives, but that doesn’t mean they aren't in the exam! Do you know?

Thank you, JJ
Seeing that some people have posted about their less-than-ideal certification experience, I’ll share mine and what I would have done if I had known what the test was really like.

I took the Oracle Java SE: Programming I course (https://education.oracle.com/java-se-programming-i-ed-2/courP_10211). I studied the material thoroughly, and the topics matched up with the published exam topics, so I reckoned that I would be adequately prepared for the 1z0-815 exam.

I took the test on October 1 2019. Unfortunately I failed the exam with 60% (pass mark is 63%). I got 2-3 too many questions wrong; I would not have been happy with just scraping through with 63%, however.

When I started my exam, for the first time in my life I got that sinking feeling; I realised that my knowledge was not up to scratch. While I had a good grasp of the theory behind most of the concepts, I realised that my knowledge of the actual code was not what it should be, especially in regard to knowing the API (mostly StringBuilder, String and Arrays methods). Probably this was also aggravated by the fact that I had been introduced to Java just four and a bit months before, so I didn’t have a lot of hands-on coding experience. I also found the code harder to read than I expected; I had always used an IDE.

It would really help if the exam topics weren’t vague and misleading. I was taken aback when I got a question starring generic methods, which I didn’t know existed (the question was about overloading and overriding). I also got other concepts which I thought would only appear in the 1z0-816 exam, collections in particular, which I had not studied. The Oracle course I took covered neither generics nor collections (apart from using ArrayLists, but pretty much only as a substitute for arrays). I was also not prepared for some of the lambda questions; I knew the basic syntax but not the different functional interfaces.

If I could rewind the past I would definitely go through the Enthuware tests and study all of the questions carefully. I would also search online to see other people’s experiences, and what the challenges are. I would have also taken my time and not rushed into the exam prematurely. To improve my code reading skills, I practise writing code in an ordinary text editor (some in vi, but it really slows me down), and also the practise tests help with experience reading the kind of code you will get in the exam.

I’m not put off by this setback, however. I’m studying hard, and I plan to retake and pass the test soon. Watch this space!

3 weeks ago
What they mean by

"Notice we said 'stop at' rather than 'include'. This means endIndex parameter is allowed to be 1 past the end of the sequence if you want to stop at the end of the sequence."

is that the substring method gets everything up to the character whose index is the value of the endIndex parameter. Example:

Notice that index 5 does not exist. Because substring only takes the characters up to the index of the endIndex (it does not take the character at index of endIndex), it stops on the character before, at index 4. So to get the end of the string, you have to pass substring an int value of one more than the original string's length.