Java 8 support

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aschulze
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Re: Java 8 support

Postby aschulze » Sun Sep 18, 2016 11:21 am

I actually followed the post of JOAN49 and used the names as stated in the post.

aschulze
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Re: Java 8 support

Postby aschulze » Wed Sep 28, 2016 5:46 am

After playing around a bit with the Java 8 JVM (Compact Profile 2) I agree with Andy - I will switch back to Java 7, mainly because the Java 8 VM needs 5 seconds more to start a simple program than the Java 7 VM (8.5 seconds compared to 13.5 seconds). Just to let you know.

cmorriss
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Re: Java 8 support

Postby cmorriss » Mon Nov 07, 2016 12:45 am

I spent several hours getting Java 8 to correctly extract. I'm not sure if anyone else has had this issue, but I figured I'd post it here with the solution to help others.

Note that I tried this with both the 0.9.0 and 0.9.1 EV3 leJOS builds.

I use a Mac as my primary computer and while the java 7 JRE that I downloaded worked, no matter what I tried, the JRE would always fail to extract. :x

I finally tried taking the Java 7 JRE that worked fine, extracted it locally and tarred/gzipped it back up. When installing on the EV3, the extract failed!!! :shock: Tried the same rebuild of the JRE .tar.gz on a completely separate linux box, and extract failed. Tried the same process on a Windows machine and it worked fine! 8)

After figuring that out, I built the Java 8 JRE on Windows using the instructions in the replies to this post and finally had a successful installation.

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gloomyandy
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Re: Java 8 support

Postby gloomyandy » Mon Nov 07, 2016 8:30 am

Did you ever work out what the difference is between the two files (the one from Linux and the one from Windows)?
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fishfin
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Re: Java 8 support

Postby fishfin » Sun Feb 19, 2017 6:07 pm

@JOAN49, thanks to one specific info in your detailed note, I was able to get Java8 work with leJOS 0.9.1b with my EV3. Here are my details.

Win 8 (but should work with Win 7+), EV3

I first installed GNU programs 'gzip' and 'tar' to gunzip/untar the ejdk, then run the jrecreate which would work. I would name the ejre directory like so: ejre-8u33-fcs-arm-linux-sflt. But on trying to tar it back using 'tar -cvf', I would get an error "Windows could not find symlink libjsig.so", then would provide me some fix. I tried both to use the fix or not. On booting up leJOS on EV3, it would fail after 'Extracting Java' process saying 'Java not found' (or something of that type, I don't remember exactly).

So I then installed 7-zip. Also at the same time, I started naming my ejre directory as ejre1.8.0_33 (the ejre 7 had it so), then used 7-zip to tar+gzip it. The gzipped file was named ejre-8u33-arm-linux-sflt-headless.tar.gz (but the directory it contained was the one I named above). And then everything went on smoothly in the EV3 boot.

I would also like to mention that I tried the latest ejdk 8u121 and that too seems to work for the moment. I tried out just a couple of sample programs on the brick and they seem to be working fine, fingers crossed.

I don't have solid reasons to choose Java 8 over Java 7. I just like to keep just one JDK on my own machines (I have several I use - office, home, my child's to teach him to code etc.), and I use Java 8 that is used by NetBeans that I use for other purposes (not Java).

The links to the ejdk 8's I have tried and find working are here:
8u33 for lego: http://www.oracle.com/technetwork/java/ ... 00042.html
8u121 for embedded (choose download for 'ARMv5/ARMv6/ARMv7 Linux - SoftFP ABI, Little Endian 2'): http://www.oracle.com/technetwork/java/ ... index.html


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