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I am following the Nutch tutorial from https://wiki.apache.org/nutch/NutchTutorial

I have Solr 5.5.4 from the Apache site and Nutch 1.13 from the Apache site

I am using Oracle Java 7, I tried first with openjdk-7 and got the same error (below)

I follow the tutorial and get to the step where I run bin/inject and I get an exception 'Unsupported major.minor version 52.0' - which I believe is Java 8. There is no Java 8 installed on my system, this is a fresh debian install. (Full error message below)

How do I address this error?

user@Nutch-1:~/apache-nutch-1.13$ bin/nutch inject crawl/crawldb urls
Exception in thread "main" java.lang.UnsupportedClassVersionError: org/apache/nutch/crawl/Injector : 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)
user@Nutch-1:~/apache-nutch-1.13$ java -version
java version "1.7.0_80"
Java(TM) SE Runtime Environment (build 1.7.0_80-b15)
Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode)
user@Nutch-1:~/apache-nutch-1.13$ which java
/usr/bin/java
user@Nutch-1:~/apache-nutch-1.13$ /usr/bin/java -version
java version "1.7.0_80"
user@Nutch-1:~/apache-nutch-1.13$ echo $JAVA_HOME
/usr/lib/jvm/java-7-oracle/jre/
user@Nutch-1:~/apache-nutch-1.13$ cd $JAVA_HOME
user@Nutch-1:/usr/lib/jvm/java-7-oracle/jre$ bin/java -version
java version "1.7.0_80"
Java(TM) SE Runtime Environment (build 1.7.0_80-b15)
Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode)

1 Answers1

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I solved this by installing Java 8. I did a bunch of different google searches trying to dig up more info on Nutch and Java versions, and I found this https://issues.apache.org/jira/browse/NUTCH-2171 (This is a bug titled 'Upgrade Nutch Trunk to Java 1.8' and it is marked 'fixed' in Nutch 1.3)

So I did not correctly read the error message. It seems to be saying that version 52 is required for some piece of code that was loaded, I assumed that it meant java version 52 was incompatible with some piece of code that was loaded.