http://imagej.273.s1.nabble.com/Unable-to-compile-plugins-with-ImageJ-1-5x-and-Java-1-6-on-windows-tp5018444p5018448.html
> Hello,
>
> I just downloaded a fresh copy of the official stable version of ImageJ
> (version 1.50i) bundled with 64-bit Java 1.6.0_24
> from
http://wsr.imagej.net/distros/win/ij150-win-jre6.zip>
> Then I tried to compile a small plugin I wrote myself. I got a message
> that I needed to download Compiler.jar, so I said yes.
>
> Then I get this error message, and the attempt to compile the plugin halts:
>
> ImageJ 1.50i; Java 1.6.0_24 [64-bit]; Windows 7 6.1; 16MB
> of 9121MB (<1%)
>
> java.lang.UnsupportedClassVersionError:
> com/sun/tools/javac/Main : Unsupported major.minor version 52.0
>
> This plugin requires Java 1.8 or later.
>
> Obviously, the latest version of Compiler.jar is not compatible with Java
> 1.6.
>
> I looked in the plugins directory on the website and tried to download
> Compiler.jar from
>
>
https://imagej.nih.gov/ij/plugins/compiler/>
> but the problem is the same. The above link seems to point to the same
> non-working version ImageJ itself downloaded.
>
> Then I tried to copy Compiler.jar from my previous installation of ImageJ
> 1.5x to the plugin/jars folder and then everything worked as it should. The
> working Compiler.jar (compatible with java 1.6) has a file date 2015-06-26
> (probably meaning that I installed it on that day) and a filesize 1063375
> bytes. My previous installation was updated continuously since v1.49, so
> several files were inherited from the older versions.
>
> So, what is the proper way to deal with this issue?
> Upgrading to the latest version of 1.51x does not help.
> I do not want to use Java 1.8 because the 3D Viewer does not work with
> that.
>
> The workaroud for me (transfering an old version of the jar file) worked
> well, but the problem is that I need to distribute the plugin code for
> someone else to compile, and cannot send them the compatible Compiler.jar
> as an email attachement since our company security policy blocks any
> attempt on emailing .jar files.
>
> Perhaps a version of Compiler.jar compatible with Java 1.6 should have
> been included in the ij150-win-jre6.zip file?
> It seems that a Java 1.6 compatible version of Compiler.jar was included
> in ij149-jre6-64.zip.
>
> Stein
>
> --
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http://imagej.nih.gov/ij/list.html>