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Java problem (perhaps) with EJS ... anyone had this "bad class file" error?
Amy Bug
2 Posts

>Hi Folks:
>  We have been using EJS 4.3.X and also 5.0.X for research on active matter.
>We are using Macs.  We trying to keep software stable and *not* update Java or OS on machines that run these codes - so we do not lose research progress by having to rewrite  ... even to port them to a later version of EJS.  
> One computer (a laptop) abruptly failed to compile our main EJS code. Trying to run with EJSConsole.jar 4.3.7  produces this message:
>bad class file: java/util/ArrayList.class (java/util:ArrayList.class)
>class file has wrong version 52.0 should be 50.0
>please remove or make sure it appears in correct subdirectory of the class path.
>import java.util.ArrayList;
>  Is there a quick hack to fix this?  I have not updated anything manually ... my Java remains at version  1.6.0_65
>and this version of Java runs the same EJS codes very successfully on three other Macs in my lab.
>These are run under EJS 4.3.6 or 4.3.7.   Sometimes EJS 5.0 console runs these codes, but this also is machine dependent.
>   Many thanks for your help!
>   Amy Graves
>   Swarthmore College

Replies to Java problem (perhaps) with EJS ... anyone had this "bad class file" error?

Re: Java problem (perhaps) with EJS ... anyone had this "bad class file" error? -
lookang Avatar
222 Posts

I used to have this same problem before in Windows some time back using ejs 4xxx.

After I upgrade Java to latest, I speculate the issues were resolved.

U may want to test your XML or ejs files on a personal computer with latest Java version before upgrading your Labs mac to be safe.

On a separate matter, you should try the JavaScript favor of ejs modeling tool to modernise your lab simulations to run on Android and iOS too.

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