Unsupported major.minor version 52.0

[magher]

Hi,

I get the 'Unsupported major.minor version 52.0'  error message when I try to run a simple relay code.

Just so you know, this is my first attempt at running Pi4J so this may be a silly question.

The file is written, compiled, and run on a Raspberry 2B with Java 8, but I still get the version missmatch error when I run it. Are the Pi4J jars compiled with JDK7 or what am I missing out on here? 

- The PI has the latest Rasbian distro and is updated/upgraded

- Java 8 JDK is installed

- Pi4J is installed with curl -s get.pi4j.com | sudo bash and updated

- Running java -XshowSettings:properties -version  gives me...

Property settings:

    awt.toolkit = sun.awt.X11.XToolkit

    file.encoding = ANSI_X3.4-1968

    file.encoding.pkg = sun.io

    file.separator = /

    java.awt.graphicsenv = sun.awt.X11GraphicsEnvironment

    java.awt.printerjob = sun.print.PSPrinterJob

    java.class.path = .

    java.class.version = 52.0

    java.endorsed.dirs = /opt/jdk1.8.0_121/jre/lib/endorsed

    java.ext.dirs = /opt/jdk1.8.0_121/jre/lib/ext

        /usr/java/packages/lib/ext

    java.home = /opt/jdk1.8.0_121/jre

    java.io.tmpdir = /tmp

    java.library.path = /usr/java/packages/lib/arm

        /lib

        /usr/lib

    java.runtime.name = Java(TM) SE Runtime Environment

    java.runtime.version = 1.8.0_121-b13

    java.specification.name = Java Platform API Specification

    java.specification.vendor = Oracle Corporation

    java.specification.version = 1.8

    java.vendor = Oracle Corporation

    java.vendor.url = http://java.oracle.com/

    java.vendor.url.bug = http://bugreport.sun.com/bugreport/

    java.version = 1.8.0_121

    java.vm.info = mixed mode

    java.vm.name = Java HotSpot(TM) Client VM

    java.vm.specification.name = Java Virtual Machine Specification

    java.vm.specification.vendor = Oracle Corporation

    java.vm.specification.version = 1.8

    java.vm.vendor = Oracle Corporation

    java.vm.version = 25.121-b13

    line.separator = \n 

    os.arch = arm

    os.name = Linux

    os.version = 4.4.50-v7+

    path.separator = :

    sun.arch.abi = gnueabihf

    sun.arch.data.model = 32

    sun.boot.class.path = /opt/jdk1.8.0_121/jre/lib/resources.jar

        /opt/jdk1.8.0_121/jre/lib/rt.jar

        /opt/jdk1.8.0_121/jre/lib/sunrsasign.jar

        /opt/jdk1.8.0_121/jre/lib/jsse.jar

        /opt/jdk1.8.0_121/jre/lib/jce.jar

        /opt/jdk1.8.0_121/jre/lib/charsets.jar

        /opt/jdk1.8.0_121/jre/lib/jfr.jar

        /opt/jdk1.8.0_121/jre/classes

    sun.boot.library.path = /opt/jdk1.8.0_121/jre/lib/arm

    sun.cpu.endian = little

    sun.cpu.isalist = 

    sun.io.unicode.encoding = UnicodeLittle

    sun.java.launcher = SUN_STANDARD

    sun.jnu.encoding = ANSI_X3.4-1968

    sun.management.compiler = HotSpot Client Compiler

    sun.os.patch.level = unknown

    user.country = US

    user.dir = /home/pi

    user.home = /home/pi

    user.language = en

    user.name = pi

    user.timezone = 

java version "1.8.0_121"

Java(TM) SE Runtime Environment (build 1.8.0_121-b13)

Java HotSpot(TM) Client VM (build 25.121-b13, mixed mode)

- Full error message

pi@uc1:~/javaProj/raspberry $ sudo java -classpath .:classes:/opt/pi4j/lib/'*' MainApp

Exception in thread "main" java.lang.UnsupportedClassVersionError: MainApp : Unsupported major.minor version 52.0

at java.lang.ClassLoader.defineClass1(Native Method)

at java.lang.ClassLoader.defineClass(ClassLoader.java:803)

at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)

at java.net.URLClassLoader.defineClass(URLClassLoader.java:442)

at java.net.URLClassLoader.access$100(URLClassLoader.java:64)

at java.net.URLClassLoader$1.run(URLClassLoader.java:354)

at java.net.URLClassLoader$1.run(URLClassLoader.java:348)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(URLClassLoader.java:347)

at java.lang.ClassLoader.loadClass(ClassLoader.java:425)

at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)

at java.lang.ClassLoader.loadClass(ClassLoader.java:358)

at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)

Any help is appreciated  :)

Cheers