I'm not sure. I haven't had this report before. What did you use to unzip the files? Did you use Windows Explorer or a real zip program? If you used Windows Explorer / Unpack, you might try a real unzip program. One free program is Just Unzip It, which you can download here: http://www.topshareware.com/JustZIPit-download-7110.htm.
Hope this helps. Mark Dexter
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Over the summer, as part of my Uni course, I was asked rather vaguely to make myself "familiar" with Java. And the recommend textbook is a resource which is over 1000 pages long!
So far, I am really enjoying the tutorials (I am ready to begin Lesson 4) and love the style and pace of them.
The 10-15min sessions are an ideal length, I can comfortably take two at a time without getting bored.
Thanks again, and I will post more feedback once I have finished the Tuts.
Craig S
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first of all thks very much for this tutorial. I have just finished the first lesson and want to learn more.. Unfortunately the files do not work on my computer. The following messages is displayed when I try loading the (html-) file:
The Camtasia Studio video content presented here requires JavaScript to be enabled and the latest version of the Macromedia Flash Player. If you are you using a browser with JavaScript disabled please enable it now. Otherwise, please update your version of the free Flash Player by downloading here.
----
However the flash player was installed correctly and I verified that it works properly (there is a verification tool on the website of Macromedia). In addition to that the javaScript is activated. After having downloaded several files and having tried several browsers (Internet Explorer, Mozilla, Opera) I am rather disappointed.
Do you have any ideas about this failure??
Thks
Marcel
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Hi. I'm sorry to hear about your problems. Is this the Total Beginners tutorial? What operating system are you using? When you say you watched lesson 1, was that from the SourceForge project page link or the YouTube link? If you could watch it from the project page link, I think that would require the same Javascript and Flash stuff as playing them from a downloaded copy. If that is true, perhaps there is something wrong with your downloaded files instead of with your computer.
I guess one thing you could try, just for troubleshooting, would be clicking directly on the .SWF file instead of the .HTML file. If this doesn't play, I think it means that the problem is most likely with the Flash player. In that case, you could try uninstalling it and then re-installing it. Unfortunately, clicking on the SWF file doesn't give you the controls (pause, rewind, etc.).
If you have access to another computer, you could try it there and see if it works.
I've tried the files on Windows XP, Windows Vista, and Linux, and with Firefox and IE.
Good luck sorting this out. Let me know if you have any more questions. Mark Dexter
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I use this tutorials in school (real classes!!) We have XP and Internet Explorer. Some of the computers are not connected to Internet.
I have had the same message as Ashill.
First I use: install_flash_player.exe (which install Adobe Flash Player), but the problem was not solved. After that I have found: flashplayer9_install_activex_082207.exe (which install Adobe Flash Player activeX) and the problem was solved.
You need to put in google: flashplayer9_install_activex_082207.exe, to found the file.
I have experience in teaching Java using Eclipse (9th class) and have desire to make some similar tutorials like this offered here. Witch open software program can I be used to record the tutorial like yours. Were to download?
Boris Starchev
Teacher
Ruse, Bulgaria
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Thank you very much for the information. I hope this will solve the problem for others.
These tutorials were made using Camtasia Studio, which is a commercial program that costs $300 and only runs on Windows. I have also tried three other programs, two of which are open source. For Windows, there is an open-source program called Camstudio (http://camstudio.org/). For Linux, there is a program called Xvidcap (http://xvidcap.sourceforge.net/). There is also an inexpensive Linux program (costs $47) called DemoRecorder (http://www.demorecorder.com/). I have tried all of these programs for basic screen recording and they all worked for recording the screen.
I used Camtasia because (1) I already was very experienced with it and (2) it has very good post-production editing (adding callouts, replacing part of the audio, inserting, etc.).
I hope this helps. Good luck with your classes and tutorials. Mark
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at first i will thank you a lot for this wonderful tutorial, in view of your work i have learned a lot. i hope you will find the time to creat additional videos, because you are a great teacher. :)
best wishes from germany
daniel
ps: i have no problems everything works well! (xp sp2, firefox 2.0.0.7)
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thanks very much for the support. Now it's working. Awesome. I have just installed the install_activex_082207.exe . Since it was not working I have updated the Flash Player manually. Now it is working perfectly. I will start doing all the tutrials.
@Mark
Thanks a lot for the fast support. You do have a great understanding of making tutorials and providing a really fantastic support. Thanks!
Take care & have a nice weekend!
Greetings from Germany
Marcel
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Anonymous
-
2007-10-02
Hi Mark.
I did your first tutorial yesterday. It was great!! I have programming experience but haven't touched code in nearly three years, so this was a fantastic refresher and an introduction to IDEs (which I never used extensively before). And a plus point for the banjo music and overall NPR-ish feel. ;o)
FYI I'm running Mac OS X (10.4.10) and whatever the latest version of Eclipse is right now. Everything worked well.
Oh, no, actually, I did get a compile error! Eclipse insisted "resource '/TotalBeginner' does not exist" (or something like that). However the JAR worked fine despite the error.
I will do your 2nd tutorial today or tomorrow. Looking forward to it, and I hope more are coming. I don't suppose you have a web tutorial in the works? :o)
Thanks a lot!
--dan
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Thank you for the great tutorial video. I will introduce your tutorial to my students.
BTW, I noticed that the mouse cursor in the video has yellow circle to hold viewer's attention and red and blue ripples appeared when mouse is clicked. These visual effects is very helpful. Could you tell me how to add the effects to the mouse cursor?
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Thanks for your comments. The yellow highlight on the cursor is a feature of Camtasia Studio, the program I used to create the tutorials. It only works when using this program to record the screen. There is probably a way to alter the cursor in Windows or Linux, but I don't know how. Good luck with the tutorials. Mark Dexter
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Love it.
At first I thought "I don't need the remedial stuff, just tell me about Eclipse!". But after the first lesson I realized that while I don't need the remedial stuff, its good to have there so that I am not distracted with advanced java stuff, I can focus on the IDE tutorial.
Things I like:
* The banjo. At first I didn't like it. But now I love it. Its nice to have that little 10-ish second intro to grab my coffee and get ready. :) Plus, it is pleasant.
* The wrap up at the end of every episode, specifically telling us what episode we just watched, that way I don't have to remember which one is next. :)
* Repetition. "So we'll just hit <Ctrl> 1 to get ..." yeah, thats SUPER helpful, I need things pounded into my head.
* The completeness. I thought that it was an IDE tutorial, but its also an introduction to Java and TDD, very nice.
* Speed. Its slow enough that I can follow it easily, but not so slow that I want to scream.
I will certainly recommend it to others.
Thanks!
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I'm beginning an IT education in University in a few months and wanted to get some basic knowledge before starting. I know from a friend that I will be using Eclipse and Java as primary programming platform, so this is just perfect for me.
I used to code a little PHP before, and the Java concepts are very confusing when you come from that.
Thanks for making it easy! I was lost without you :)
Cheers from Denmark.
/Svante
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Anonymous
-
2007-10-23
Hey Mark,
I finally had the chance to do your second tutorial. It was as good as the first--though I did miss the banjo music.
I found the topic interesting, and I liked all the ancillary stuff you throw in, like bringing in source code for standard libraries, creating a simple manifest, fixing warnings was Ctrl-1, etc.
Thank you! I'll be looking forward to the next tutorial.
--dan
ps. Oh, there is one thing I can point to as a slight problem, though it's really just nitpicking. When you fetched the source code for the Java standard libraries, you clicked on (I think) rt.jar, and then you browsed for something like source.zip. I'm running Mac OS X, so for one thing, my machine came with Java 5 pre-installed, but no source code anywhere (or none I could find). So I had to download that separately (the file was called 'jdk-1_5_0-src-scsl.zip'). Also, I didn't have rt.jar. In fact my list of jars was substantially different than yours. I clicked on a 'classes.jar' and attached the source code to that, and everything worked. None of this was a big problem and it only took me a few extra minutes to work around, but I thought you might be interested in the discrepancy. Cheers.
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Hi Dan. Thanks for the feedback and the information. I haven't tried it on a Mac, so I wasn't aware of the differences in attaching the source code. When I revise the lessons, I'll try to remember add a note about that. Mark
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I have just finished the first tutorial (Eclipse and Java for Total Beginners)
and I have found it very helpful. I've never seen stuff like that before.
I liked very much your approach and the test-driven development.
Excellent job! I look forward to start with the second one (Introducing Persistence).
Thanks a lot!
L.
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Thanks, All is good.
Explanation is simple and precise, and tone of voice and pace is excellent.
I just wish, I find a way to download whole lessons at once.
Just being lazy...
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Firstly let me say how much I've enjoyed the tutorials (am halfway thru Persistence, which I did third). They really are absolutely excellent!!
Minor problem: Persistence (Lesson 9, I think): my XML file didn't have a local history. I checked the prefs and it all looked OK. Tried a manual edit and save, then there was one file in the local history, but only my manually edited version, not the programmatically generated ones.
Be nice to have a suggested order in which the tutorials are to be viewed. (Guess it's there if you go in from the right page and not just pick them up from resources)
A really useful future topic would be a quick overview of freely-available or reasonably priced (I mean "reasonably" for an individual) third party Java classes (like XStream) which you have found useful.
Thanks again! (Am really looking forward to the tutorials on gui, collections, Threads, database, program design ...)
Malcolm Storey
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Hi Malcolm. Thanks for the suggestions and the feedback. I renamed the packages in SourceForge to "1. Total Beginners", "2. Persistence Tutorial", and "3. Debugger Tutorial" to try to make it clear the natural order. However, I think you could easily do the debugger tutorial without having done the persistence tutorial. Anyway, this gets the downloads in the natural order if you select Download / Browse all files.
On the XML file compare with local history, I just tried this and I think you are correct. The Eclipse compare to local history only seems to work if you have saved the file from the editor. Thanks for pointing this out. I'll correct this in a future revision.
Mark
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Hi Mark,
Have just finished the Persistence tutorial.
Obviously the tutorial is only an intro and can't cover everything, but, by way of saying thank you, here are a few suggestions and questions that I felt it left hanging:
1. You offer persistence only as a means of saving a session. Apparently there are advanced uses like interprocess or intersystem communication which could also be mentioned in passing. It also looks a good way of saving config info.
2. Am not sure if you said this, but objects seem to be rebuilt from the latest class definition and then populated from the datafile. They don't pass thru the constructor (even if there is a parameterless constructor) [This is all probably "obvious" when you understand Java a bit better than a beginner like me!!]
3. Once your program is wrapped in object persistence, as you develop it and add/change fields in a class, will that class still be matched to its definition next time you launch the program?
4. If you add a new object ref to a class, even if the class is recognised, the ref won't get initialised - a case for lazy initialisation?
5. How does serialisation handle repeated or circular references? You explained this in XStream, but not in object serialisation. [seems to be the same - just looked it up]
6. How do you handle fields that shouldn't be saved? These might be trivial things that could be fixed with a "refresh" operation (eg current date in a calendar), or system resources - am not sure how deep serialisation goes but what happens if you serialise a system-level window pointer? Or a client in an FTP host? Are there implications if using with GUI components? I see Thread's are not serializable so it looks like "they"'ve thought of this one!
Persistence looks like one of those things best added right at the beginning of development, but not really usable until you've finished the project.
Hi Malcolm. Thanks for the comments. I'll respond briefly to each one.
1. You are correct that there are many ways to use persistence. I was just trying to present the simplest example in conjunction with the MyLibrary project.
2. Since we first get an Object and then cast it into a MyLibrary object, I think you are right that the constructor is not executed. I just did some searching in my books and on the web and can't find a quick answer on that. I just did a quick test where I added a new field to the Person class and set it to a default value. When I get an existing MyLibrary from a serialzed file created before I added the new field, it works but the new field is null, not the default value. So this would appear to confirm that the constructor was not executed.
3. This is a complicated subject, as is anything to do with backward compatibility. With serialization, the reason we use the serialVersionUID field is to have control over this. If you don't use the serialVersionUID, ANY change to the class will cause it not to accept an older serialized object (since the calculated UID will have changed). As I understand it, it's ok to add new fields as long as it's ok for them to have a null value initially. (See (2) above.)
4. Yes. Same as (3) above.
5. You already figured this one out. It's just harder to see, because it's all behind the scenes.
6. You can tag fields to not be saved with both serialization and with XStream. I thought this was beyond the scope of what I wanted to try to cover.
I agree that you would normally plan for persistence at the start of a project, although the way it was developed here seems to work. Thanks for the references. I'll include them in the companion document.
Thanks. Mark
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Anonymous
-
2007-11-26
Hi,
I am a complete newbie in both Java and Eclipse - just got a job working using both. :)
I went through the tutorials in like two and half days. I thought they were a great introduction. Most valuable! Thank You!
One thing that I noticed: I lesson 12, on one of the first slides you introduce what the code is going to do. By this time, I normally wrote this into my source as commnets, and tried to figure out the code on my own before going on with the tutorial. By the time the lesson is completed, the code that you give follows a different path than what you have presented. Have a look at the slide and then the final code. You should change the slide that introduces the code, so that it is the same as the flow of the code.
M.
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Hi. Thanks for the feedback. In the point on lesson 12, I assume you're referring to the Total Beginners tutorial? Could you please be a little more specific on the difference between the slide and the actual code and what you think the slide should say? I want to make sure I understand the problem.
This is very good timing, since I'm just releasing a new version of the tutorials with close-caption subtitles. So it will be easy for me to fix this now. Thanks. Mark
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I'm not sure. I haven't had this report before. What did you use to unzip the files? Did you use Windows Explorer or a real zip program? If you used Windows Explorer / Unpack, you might try a real unzip program. One free program is Just Unzip It, which you can download here: http://www.topshareware.com/JustZIPit-download-7110.htm.
Hope this helps. Mark Dexter
Thank you thank you thank you.
Over the summer, as part of my Uni course, I was asked rather vaguely to make myself "familiar" with Java. And the recommend textbook is a resource which is over 1000 pages long!
So far, I am really enjoying the tutorials (I am ready to begin Lesson 4) and love the style and pace of them.
The 10-15min sessions are an ideal length, I can comfortably take two at a time without getting bored.
Thanks again, and I will post more feedback once I have finished the Tuts.
Craig S
Hi Mark,
first of all thks very much for this tutorial. I have just finished the first lesson and want to learn more.. Unfortunately the files do not work on my computer. The following messages is displayed when I try loading the (html-) file:
The Camtasia Studio video content presented here requires JavaScript to be enabled and the latest version of the Macromedia Flash Player. If you are you using a browser with JavaScript disabled please enable it now. Otherwise, please update your version of the free Flash Player by downloading here.
----
However the flash player was installed correctly and I verified that it works properly (there is a verification tool on the website of Macromedia). In addition to that the javaScript is activated. After having downloaded several files and having tried several browsers (Internet Explorer, Mozilla, Opera) I am rather disappointed.
Do you have any ideas about this failure??
Thks
Marcel
Hi. I'm sorry to hear about your problems. Is this the Total Beginners tutorial? What operating system are you using? When you say you watched lesson 1, was that from the SourceForge project page link or the YouTube link? If you could watch it from the project page link, I think that would require the same Javascript and Flash stuff as playing them from a downloaded copy. If that is true, perhaps there is something wrong with your downloaded files instead of with your computer.
I guess one thing you could try, just for troubleshooting, would be clicking directly on the .SWF file instead of the .HTML file. If this doesn't play, I think it means that the problem is most likely with the Flash player. In that case, you could try uninstalling it and then re-installing it. Unfortunately, clicking on the SWF file doesn't give you the controls (pause, rewind, etc.).
If you have access to another computer, you could try it there and see if it works.
I've tried the files on Windows XP, Windows Vista, and Linux, and with Firefox and IE.
Good luck sorting this out. Let me know if you have any more questions. Mark Dexter
Hi, Mark Dexter
I use this tutorials in school (real classes!!) We have XP and Internet Explorer. Some of the computers are not connected to Internet.
I have had the same message as Ashill.
First I use: install_flash_player.exe (which install Adobe Flash Player), but the problem was not solved. After that I have found: flashplayer9_install_activex_082207.exe (which install Adobe Flash Player activeX) and the problem was solved.
You need to put in google: flashplayer9_install_activex_082207.exe, to found the file.
I have experience in teaching Java using Eclipse (9th class) and have desire to make some similar tutorials like this offered here. Witch open software program can I be used to record the tutorial like yours. Were to download?
Boris Starchev
Teacher
Ruse, Bulgaria
Thank you very much for the information. I hope this will solve the problem for others.
These tutorials were made using Camtasia Studio, which is a commercial program that costs $300 and only runs on Windows. I have also tried three other programs, two of which are open source. For Windows, there is an open-source program called Camstudio (http://camstudio.org/). For Linux, there is a program called Xvidcap (http://xvidcap.sourceforge.net/). There is also an inexpensive Linux program (costs $47) called DemoRecorder (http://www.demorecorder.com/). I have tried all of these programs for basic screen recording and they all worked for recording the screen.
I used Camtasia because (1) I already was very experienced with it and (2) it has very good post-production editing (adding callouts, replacing part of the audio, inserting, etc.).
I hope this helps. Good luck with your classes and tutorials. Mark
hi, mark
at first i will thank you a lot for this wonderful tutorial, in view of your work i have learned a lot. i hope you will find the time to creat additional videos, because you are a great teacher. :)
best wishes from germany
daniel
ps: i have no problems everything works well! (xp sp2, firefox 2.0.0.7)
Thanks Daniel. Be sure to look at the Introducing Persistence tutorial that I just finished a few days ago. Mark
Hi guys,
thanks very much for the support. Now it's working. Awesome. I have just installed the install_activex_082207.exe . Since it was not working I have updated the Flash Player manually. Now it is working perfectly. I will start doing all the tutrials.
@Mark
Thanks a lot for the fast support. You do have a great understanding of making tutorials and providing a really fantastic support. Thanks!
Take care & have a nice weekend!
Greetings from Germany
Marcel
Hi Mark.
I did your first tutorial yesterday. It was great!! I have programming experience but haven't touched code in nearly three years, so this was a fantastic refresher and an introduction to IDEs (which I never used extensively before). And a plus point for the banjo music and overall NPR-ish feel. ;o)
FYI I'm running Mac OS X (10.4.10) and whatever the latest version of Eclipse is right now. Everything worked well.
Oh, no, actually, I did get a compile error! Eclipse insisted "resource '/TotalBeginner' does not exist" (or something like that). However the JAR worked fine despite the error.
I will do your 2nd tutorial today or tomorrow. Looking forward to it, and I hope more are coming. I don't suppose you have a web tutorial in the works? :o)
Thanks a lot!
--dan
Hi,
Thank you for the great tutorial video. I will introduce your tutorial to my students.
BTW, I noticed that the mouse cursor in the video has yellow circle to hold viewer's attention and red and blue ripples appeared when mouse is clicked. These visual effects is very helpful. Could you tell me how to add the effects to the mouse cursor?
Thanks for your comments. The yellow highlight on the cursor is a feature of Camtasia Studio, the program I used to create the tutorials. It only works when using this program to record the screen. There is probably a way to alter the cursor in Windows or Linux, but I don't know how. Good luck with the tutorials. Mark Dexter
Love it.
At first I thought "I don't need the remedial stuff, just tell me about Eclipse!". But after the first lesson I realized that while I don't need the remedial stuff, its good to have there so that I am not distracted with advanced java stuff, I can focus on the IDE tutorial.
Things I like:
* The banjo. At first I didn't like it. But now I love it. Its nice to have that little 10-ish second intro to grab my coffee and get ready. :) Plus, it is pleasant.
* The wrap up at the end of every episode, specifically telling us what episode we just watched, that way I don't have to remember which one is next. :)
* Repetition. "So we'll just hit <Ctrl> 1 to get ..." yeah, thats SUPER helpful, I need things pounded into my head.
* The completeness. I thought that it was an IDE tutorial, but its also an introduction to Java and TDD, very nice.
* Speed. Its slow enough that I can follow it easily, but not so slow that I want to scream.
I will certainly recommend it to others.
Thanks!
I must say, this is some super awesome tutorials!
I'm beginning an IT education in University in a few months and wanted to get some basic knowledge before starting. I know from a friend that I will be using Eclipse and Java as primary programming platform, so this is just perfect for me.
I used to code a little PHP before, and the Java concepts are very confusing when you come from that.
Thanks for making it easy! I was lost without you :)
Cheers from Denmark.
/Svante
Hey Mark,
I finally had the chance to do your second tutorial. It was as good as the first--though I did miss the banjo music.
I found the topic interesting, and I liked all the ancillary stuff you throw in, like bringing in source code for standard libraries, creating a simple manifest, fixing warnings was Ctrl-1, etc.
Thank you! I'll be looking forward to the next tutorial.
--dan
ps. Oh, there is one thing I can point to as a slight problem, though it's really just nitpicking. When you fetched the source code for the Java standard libraries, you clicked on (I think) rt.jar, and then you browsed for something like source.zip. I'm running Mac OS X, so for one thing, my machine came with Java 5 pre-installed, but no source code anywhere (or none I could find). So I had to download that separately (the file was called 'jdk-1_5_0-src-scsl.zip'). Also, I didn't have rt.jar. In fact my list of jars was substantially different than yours. I clicked on a 'classes.jar' and attached the source code to that, and everything worked. None of this was a big problem and it only took me a few extra minutes to work around, but I thought you might be interested in the discrepancy. Cheers.
Hi Dan. Thanks for the feedback and the information. I haven't tried it on a Mac, so I wasn't aware of the differences in attaching the source code. When I revise the lessons, I'll try to remember add a note about that. Mark
Hi Mark,
These are really cool videos, they are really easy to follow.
I wish more people would do stuff like this.
I'm on video 6 now, I will report back in the unlikely event that I will find any improvements to suggest.
Hi Mark,
I have just finished the first tutorial (Eclipse and Java for Total Beginners)
and I have found it very helpful. I've never seen stuff like that before.
I liked very much your approach and the test-driven development.
Excellent job! I look forward to start with the second one (Introducing Persistence).
Thanks a lot!
L.
Thanks, All is good.
Explanation is simple and precise, and tone of voice and pace is excellent.
I just wish, I find a way to download whole lessons at once.
Just being lazy...
Firstly let me say how much I've enjoyed the tutorials (am halfway thru Persistence, which I did third). They really are absolutely excellent!!
Minor problem: Persistence (Lesson 9, I think): my XML file didn't have a local history. I checked the prefs and it all looked OK. Tried a manual edit and save, then there was one file in the local history, but only my manually edited version, not the programmatically generated ones.
Be nice to have a suggested order in which the tutorials are to be viewed. (Guess it's there if you go in from the right page and not just pick them up from resources)
A really useful future topic would be a quick overview of freely-available or reasonably priced (I mean "reasonably" for an individual) third party Java classes (like XStream) which you have found useful.
Thanks again! (Am really looking forward to the tutorials on gui, collections, Threads, database, program design ...)
Malcolm Storey
Hi Malcolm. Thanks for the suggestions and the feedback. I renamed the packages in SourceForge to "1. Total Beginners", "2. Persistence Tutorial", and "3. Debugger Tutorial" to try to make it clear the natural order. However, I think you could easily do the debugger tutorial without having done the persistence tutorial. Anyway, this gets the downloads in the natural order if you select Download / Browse all files.
On the XML file compare with local history, I just tried this and I think you are correct. The Eclipse compare to local history only seems to work if you have saved the file from the editor. Thanks for pointing this out. I'll correct this in a future revision.
Mark
Hi Mark,
Have just finished the Persistence tutorial.
Obviously the tutorial is only an intro and can't cover everything, but, by way of saying thank you, here are a few suggestions and questions that I felt it left hanging:
1. You offer persistence only as a means of saving a session. Apparently there are advanced uses like interprocess or intersystem communication which could also be mentioned in passing. It also looks a good way of saving config info.
2. Am not sure if you said this, but objects seem to be rebuilt from the latest class definition and then populated from the datafile. They don't pass thru the constructor (even if there is a parameterless constructor) [This is all probably "obvious" when you understand Java a bit better than a beginner like me!!]
3. Once your program is wrapped in object persistence, as you develop it and add/change fields in a class, will that class still be matched to its definition next time you launch the program?
4. If you add a new object ref to a class, even if the class is recognised, the ref won't get initialised - a case for lazy initialisation?
5. How does serialisation handle repeated or circular references? You explained this in XStream, but not in object serialisation. [seems to be the same - just looked it up]
6. How do you handle fields that shouldn't be saved? These might be trivial things that could be fixed with a "refresh" operation (eg current date in a calendar), or system resources - am not sure how deep serialisation goes but what happens if you serialise a system-level window pointer? Or a client in an FTP host? Are there implications if using with GUI components? I see Thread's are not serializable so it looks like "they"'ve thought of this one!
Persistence looks like one of those things best added right at the beginning of development, but not really usable until you've finished the project.
Your accompanying PDF has no refs for serialisation. Here are a couple that could be added, (expect you know these or better):
http://java.sun.com/developer/technicalArticles/Programming/serialization/
http://www.beginner-java-tutorial.com/object-serialization.html
Keep up the good work, am really looking forward to the next tutorial!
Malcolm Storey
Hi Malcolm. Thanks for the comments. I'll respond briefly to each one.
1. You are correct that there are many ways to use persistence. I was just trying to present the simplest example in conjunction with the MyLibrary project.
2. Since we first get an Object and then cast it into a MyLibrary object, I think you are right that the constructor is not executed. I just did some searching in my books and on the web and can't find a quick answer on that. I just did a quick test where I added a new field to the Person class and set it to a default value. When I get an existing MyLibrary from a serialzed file created before I added the new field, it works but the new field is null, not the default value. So this would appear to confirm that the constructor was not executed.
3. This is a complicated subject, as is anything to do with backward compatibility. With serialization, the reason we use the serialVersionUID field is to have control over this. If you don't use the serialVersionUID, ANY change to the class will cause it not to accept an older serialized object (since the calculated UID will have changed). As I understand it, it's ok to add new fields as long as it's ok for them to have a null value initially. (See (2) above.)
4. Yes. Same as (3) above.
5. You already figured this one out. It's just harder to see, because it's all behind the scenes.
6. You can tag fields to not be saved with both serialization and with XStream. I thought this was beyond the scope of what I wanted to try to cover.
I agree that you would normally plan for persistence at the start of a project, although the way it was developed here seems to work. Thanks for the references. I'll include them in the companion document.
Thanks. Mark
Hi,
I am a complete newbie in both Java and Eclipse - just got a job working using both. :)
I went through the tutorials in like two and half days. I thought they were a great introduction. Most valuable! Thank You!
One thing that I noticed: I lesson 12, on one of the first slides you introduce what the code is going to do. By this time, I normally wrote this into my source as commnets, and tried to figure out the code on my own before going on with the tutorial. By the time the lesson is completed, the code that you give follows a different path than what you have presented. Have a look at the slide and then the final code. You should change the slide that introduces the code, so that it is the same as the flow of the code.
M.
Hi. Thanks for the feedback. In the point on lesson 12, I assume you're referring to the Total Beginners tutorial? Could you please be a little more specific on the difference between the slide and the actual code and what you think the slide should say? I want to make sure I understand the problem.
This is very good timing, since I'm just releasing a new version of the tutorials with close-caption subtitles. So it will be easy for me to fix this now. Thanks. Mark