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I'm really new to Java and I'd like to ask you ,which aspects of Java SE are considered to be necessary for someone wanting to learn Java ME? Something like prerequisites.

To start with Java SE, I chose this book, but since I don't have much time, it would be great to hear from experienced developers which parts I should definitely focus on and which parts I could skip to save time.

If is there any topic from Java SE that could also be considered a prerequisite for Java ME, feel free to mention it.

halfer
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eddy
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2 Answers2

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According to content in the book that you mentioned in the questions

  • Section 1 is must, would teach you basics about java.
  • Section 2: If you have already worked in any oo language then you can skip this section and come back to it later stage.
  • Section 3 and Section 6 will be good for you as the code you need to write , need to be memory efficient and multi-threaded.
sudmong
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  • Just curious why he needs us to regurgitate this basic information which is in the book that he already owns. – Hovercraft Full Of Eels May 14 '14 at 12:41
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    @HovercraftFullOfEels I didn't say that already own that book. Based on your comments I might go for another book. – eddy May 14 '14 at 12:48
  • @sudmong just out of sheer curiosity , is it Swing completely different from the UI that java ME uses?? I mean, aren't they related at all??? – eddy May 14 '14 at 14:04
  • Not much about it as I never worked on J2ME. But yes I have worked on mobile app development using Android and PhoneGap. I have swing for desktop app development and found it to be quite heavy for mobile development. A quick search on google reveals that there are some frameworks(not sure if they are based on swing) for UI in J2ME. http://stackoverflow.com/questions/116394/java-me-ui-libraries http://developer.nokia.com/community/wiki/Java_ME_UI_Frameworks – sudmong May 15 '14 at 07:30
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If you really need to learn JavaME from Java SE, then you should read an old Java SE 1.4 book, and just stick to the basics of the language.

Why? Well Java ME is based on JRE 1.3, so there are no generics, no collections (added in Java 6) and let alone Java 8's new stuff. If you buy a recent Java SE book, you might get confused because you won't be able to use these new features.

Second thing that differs, it is not an homogeneous platform. It is divided in two parts (CLDC/CDC for the core classes, and MIDP for the GUI classes). And there are optional profiles (JSRs) that migh or might not be supported in a certain device.

Other than this, you should always keep an eye on memory efficiency. Old devices do not have much RAM, so you should never try to load large images or data in memory, and always free resources when not used.

Mister Smith
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