How to resolve java : not found?

Question

I execute the command sudo cassandra -R to start cassandra and I get the following error.

getopt: invalid option -- 'R'
/usr/sbin/cassandra: 158: exec: java: not found

It points to the following line in the cassandra script.

else
        exec $NUMACTL "$JAVA" $JVM_OPTS $cassandra_parms -cp "$CLASSPATH"

Is it because the environment variable JAVA is not set? If yes, how to set the variable?

The output of echo $JAVA_HOME is blank. This is the output of java -version:

java version "1.8.0_161"
Java(TM) SE Runtime Environment (build 1.8.0_161-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.161-b12, mixed mode)

Well *is* `$JAVA` set? Please [edit] and provide the output of `echo $JAVA` and `java -version`. — dessert, May 18 '18 at 06:22
Please run `JAVA=$(which java) && sudo cassandra` – let’s see whether it’s as simple as that. :) — dessert, May 18 '18 at 06:36
Did you follow the installation instructions for cassandra at http://cassandra.apache.org/doc/latest/getting_started/installing.html ? — Sebastian Stark, May 27 '18 at 11:00

score 0 · Answer 1 · answered May 16 '22 at 07:33

A simple solution for that is to set JAVA_HOME variable to point to your java installation. The cassandra script should generally autodeetect your java location on PATH, but if it doesn't happen, you can help with setting JAVA_HOME explicitly:

export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64/

Note: you must set JAVA_HOME not JAVA. JAVA variable is used internally by the cassandra launch scripts, but you're not supposed to set it. JAVA is set by this code snippet in cassandra.in.sh:

# Use JAVA_HOME if set, otherwise look for java in PATH
if [ -n "$JAVA_HOME" ]; then
    # Why we can't have nice things: Solaris combines x86 and x86_64
    # installations in the same tree, using an unconventional path for the
    # 64bit JVM.  Since we prefer 64bit, search the alternate path first,
    # (see https://issues.apache.org/jira/browse/CASSANDRA-4638).
    for java in "$JAVA_HOME"/bin/amd64/java "$JAVA_HOME"/bin/java; do
        if [ -x "$java" ]; then
            JAVA="$java"
            break
        fi
    done
else
    JAVA=`command -v java 2> /dev/null`
fi

How to resolve java : not found?

1 Answers1