cassandra 2 complaining about Java 7 when I have Java 7 installed

Question

$ cassandra 
Cassandra 2.0 and later require Java 7 or later.

OK, what's going on in that part of the init script?

java_ver_output=`"${JAVA:-java}" -version 2>&1`

jvmver=`echo "$java_ver_output" | awk -F'"' 'NR==1 {print $2}'`
JVM_VERSION=${jvmver%_*}
JVM_PATCH_VERSION=${jvmver#*_}


if [ "$JVM_VERSION" \< "1.7" ] ; then
    echo "Cassandra 2.0 and later require Java 7 or later."
    exit 1;
fi

Hmm, if I get the version at the command line:

$ java_ver_output=`"${JAVA:-java}" -version 2>&1`

$ echo $java_ver_output
java version "1.7.0_55" Java(TM) SE Runtime Environment (build 1.7.0_55-b13) Java HotSpot(TM) 64-Bit Server VM (build 24.55-b03, mixed mode)

$ JVM_VERSION=${jvmver%_*}

$ echo $JVM_VERSION
1.7.0

If I run which java:

$ which java
/usr/bin/java

If I put that line in the script:

/usr/bin/java

The frustrating part here is that I've got this running in the past but since I bounced the server I can't get cassandra to start.

So I'm confused here, how is Cassandra confused about what version of Java I'm running? How do I get cassandra running? Is 1.7.0_55 not Java 7 (I don't get Java's naming convention)?

Answer 1

I got the same error message when trying to start Cassandra. But I notised that I only got the error when starting Cassandra as root. It worked when I started Cassandra as my local user.

It turned out that java only was configured for my local user:

$ java -version
java version "1.7.0_60"
Java(TM) SE Runtime Environment (build 1.7.0_60-b19)
Java HotSpot(TM) 64-Bit Server VM (build 24.60-b09, mixed mode)
$ sudo java -version
sudo: java: command not found

This fixed the problem:

Tell the system that you have JRE installed (update usr/local/java/jre1.7.0_60/bin/java to your current path):

$ sudo update-alternatives --install "/usr/bin/java" "java" "/usr/local/java/jre1.7.0_60/bin/java" 1

Set the new JRE as default:

$ sudo update-alternatives --set java /usr/local/java/jre1.7.0_60/bin/java

Now java is installed for root and Cassandra can be started as root without the error message.