zookeeper: Unsupported major.minor version 52.0

Question

I'm trying to follow the guide on the kafka website: https://kafka.apache.org/quickstart But when I use kafka_2.12-2.5.0 and try to start the zookeeper I get:

$ bin/zookeeper-server-start.sh  config/zookeeper.properties
    Exception in thread "main" java.lang.UnsupportedClassVersionError: org/apache/zookeeper/server/quorum/QuorumPeerMain : Unsupported major.minor version 52.0
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)

I'm using redhat7.1. Tried to update java:

$ sudo yum install java-1.8.0-openjdk-devel
Loaded plugins: langpacks, product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
...
Package 1:java-1.8.0-openjdk-devel-1.8.0.31-2.b13.el7.x86_64 already installed and latest version
Nothing to do

What version of Java should I have?

Answer 1

This '52.0' means that it's compiled with 1.8 jdk, but you are triying to run mainly with lower one (or even very high incompatible?). By default use the JAVA_HOME environment variable, so hope you already checked the basics: java_home, java --version... or even force an export of java_home just before running pointing a proper 32/64 java