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Cassandra: Unable to find java executable

I am starting to learn cassandra and downloaded the file from the Apache Cassandra. When I navigated through the bin folder of the apache-cassandra-2.2.1/bin and run the command cassandra it gives me the error saying Unable to find java executable. Check JAVA_HOME and PATH environment variables.
But at the same path when I hit java I am able to see the java is accessible there. What should I do to get rid of this? I am using Windows OS.
Edit:
I rather used Datastax windows installer and now I see no error in running cqlsh.

I was also facing the same problem. Actually, somewhere in installation scripts it adds "bin/java" to "$JAVA_HOME". In my case, java path was "/usr/bin/java" so I had to configure $JAVA_HOME=/user.
export JAVA_HOME=/usr/

Set JAVA_HOME:
Right click My Computer and select Properties.
On the Advanced tab, select Environment Variables, and then edit JAVA_HOME to point to where the JDK software is located, for example, C:\Program Files\Java\jdk1.6.0_02.
FROM:
http://docs.oracle.com/cd/E19182-01/820-7851/inst_cli_jdk_javahome_t/index.html

login with root because Cassandra will start with the root
readlink -f $(which java)
vi ~/.bashrc
source ~/.bashrc
please note: java version should be same on cluster nodes
BR// nitin.k

Nutch Error: JAVA_HOME is not set

I followed this tutorial http://saskia-vola.com/nutch-2-2-elasticsearch-1-x-hbase/ When I finally tried to run Nutch sudo bin/nutch inject urls I got this error
Error: JAVA_HOME is not set.
but when I echo JAVA_HOME it returns
/usr/lib/jvm/java-7-openjdk-amd64
and it is also in /etc/environment
JAVA_HOME="/usr/lib/jvm/java-7-openjdk-amd64"
and also I added line to end of file ~/.bashrc
export JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64
but it still returns this error. How can I fix it?

You are running the command as root user, so the environment variables the application sees are the one's visible for root user not your user. Just check that the root has a JAVA_HOME environment variable set or run the program as your user, if possible.
You can try sudo -E bin/nutch inject urls
As the sudo manual says,
-E, --preserve-env
Indicates to the security policy that the user wishes to preserve their existing environment variables. The security policy may return an error if the user does not have permission to preserve the environment.

make sure that the full JDK is there not only the JVM. you can also override this by export JAVA_HOME=YOUR_PREFERED_JDK_PATH in .bashrc file in you home directory.

Probably you didn't set java path in /etc/environment. Try given command.
sudo vi /etc/environment
and then set Java path
JAVA_PATH=/give your java path here/
You can check java path by using $JAVA_HOME, and then use
sudo -E bin/nutch inject urls

Why JAVA_HOME not recognized by tomcat7 in Ubuntu?

I have installed tomcat7 on my Ubuntu machine. When I try to restart the server I get message to set JAVA_HOME but it is set in .bashrc
export JAVA_HOME=/usr/lib/jvm/java-8-oracle
export CATALINA_HOME=/usr/share/tomcat7
Error:
omkars#<ubuntu_14.04>:~$ sudo service tomcat7 restart
[sudo] password for omkars:
* no JDK or JRE found - please set JAVA_HOME
omkars#<ubuntu_14.04>:~$ echo $JAVA_HOME
/usr/lib/jvm/java-8-oracle
What could be missing ?
Thanks.

Now, its working!
Changes I have done are:
changed .bashrc as explained in the question.
changed /etc/init.d/tomcat7 to point to oracle Java8 which is missing here!
JDK_DIRS="/usr/lib/jvm/default-java ${OPENJDKS} /usr/lib/jvm/java-6-openjdk /usr/lib/jvm/java-6-sun /usr/lib/jvm/java-7-oracle **/usr/lib/jvm/java-8-oracle**"
Then,
root#omkars-Dell-System-Inspiron-N4110:~# sudo service tomcat7 restart
* Starting Tomcat servlet engine tomcat7 [ OK ]
Got a hint from this page:
https://mifosforge.jira.com/wiki/display/MIFOSX/Install+Tomcat+7+on+Ubuntu+11.10+for+Mifos+X
Thanks

It seems like the preferred way of handling this is to uncomment the JAVA_HOME entry in /etc/default/tomcat7 and adjust the path accordingly. If you're using the webupd8 repository with the oracle-java8-installer, it's JAVA_HOME=/usr/lib/jvm/java-8-oracle.

It'll need to be set for the user that runs the tomcat service, rather than for your user.
Set it in the system wide profile, somewhere in /etc/profile or /etc/profile.d/, depending on how your machine is configured.

The startup script at /etc/init.d/tomcat7 sources the file /etc/default/rcS before searching for some well-known install locations.
Adding the line JAVA_HOME=/usr/lib/jvm/java-8-oracle to /etc/default/rcS corrects the no JDK or JRE found startup problem without directly modifying the /etc/init.d/tomcat7 script.

You can set an environmental variable in the setenv.sh script. According to the Running The Apache Tomcat 7.0 document:
Apart from CATALINA_HOME and CATALINA_BASE, all environment variables can
be specified in the "setenv" script. The script is placed either into
CATALINA_BASE/bin or into CATALINA_HOME/bin directory and is named
setenv.bat (on Windows) or setenv.sh (on *nix).
So just add the following line to setenv.sh:
export JAVA_HOME=/usr/lib/jvm/java-8-oracle
This way you are setting the variable locally.

I have that same problem but I solve it by changing
JDK_DIR variable in /etc/init.d/tomcat as follow :
JDK_DIRS="/usr/lib/jvm/default-java ${OPENJDKS} /usr/lib/jvm/java-6-openjdk /usr/lib/jvm/java-6-sun /usr/lib/jvm/java-7-oracle /usr/lib/jvm/java-8-oracle"

Try install Java using the repository of http://www.webupd8.org .
This is for Java 8: http://www.webupd8.org/2012/09/install-oracle-java-8-in-ubuntu-via-ppa.html

'JAVA_HOME is not set' error while installing pig. What to do about it?

I followed all the steps on pig.apache.org ,but not able to remove this error by setting java variable. I set the variable earlier while installing java jdk but its asking again for the variable.

You need to understand how environment variables work in Linux (or Windows).
The chances are that you only set JAVA_HOME temporarily in the shell that you used to do the installation. To set JAVA_HOME permanently (on Linux / UNIX) you need to set it in a shell "rc" file that gets run each time a new shell is created. (It depends on which shell you are using, but man can tell you about that ...)

if you are installing PIG on ubuntu do this
open bashrc file using below command and and lines to the end of the file
vi ~/.bashrc
export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk-i386
then log out or Restart your system and try again.
For CentOS
Create a new file called java.sh
vim /etc/profile.d/java.sh
Within this file, initialize the necessary environment variables
export JRE_HOME=/usr/java/jdk1.5.0_12/jre
export PATH=$PATH:$JRE_HOME/bin
export JAVA_HOME=/usr/java/jdk1.5.0_12
export JAVA_PATH=$JAVA_HOME
export PATH=$PATH:$JAVA_HOME/bin
Replace java path with your java installation.
Source

To set your JAVA_HOME variable for your current shell, use the export command. This will immediately create an environment variable for JAVA_HOME, but the variable is lost when your shell is closed.
export JAVA_HOME=<path_to_java_sdk>
The best way to set the JAVA_HOME environment variable for Pig and Hadoop use is by adding it to your local rc file. The reason for this is that some distributions of Hadoop (Cloudera, Hortonworks, MapR) may include their own Java installation for the Hadoop application itself. You may not want to create a global environment variable, since it may interfere with Hadoop/Hive/etc.
To have the variable set for individual Hadoop/Pig users on the server, they need to run the following command:
echo "export JAVA_HOME=<path_to_java_sdk>" >> ~/.bashrc
Afterward executing the command, they can source ~/.bashrc to instantiate the environment variable.

What should I set JAVA_HOME environment variable on macOS X 10.6?

Many Java applications that use shell scripts to configure their environment use the JAVA_HOME environment variable to start the correct version of Java, locate JRE JARs, and so on.
In macOS X 10.6, the following paths seem to be valid for this variable
/Library/Java/Home
/System/Library/Frameworks/JavaVM.framework/Home
/System/Library/Frameworks/JavaVM.framework/Versions/Current
Some of these are symlinks to the actual current VM (as defined in the Java Preference pane).
But which one should be used—or is it okay to use any of them?

I just set JAVA_HOME to the output of that command, which should give you the Java path specified in your Java preferences. Here's a snippet from my .bashrc file, which sets this variable:
export JAVA_HOME=$(/usr/libexec/java_home)
I haven't experienced any problems with that technique.
Occasionally I do have to change the value of JAVA_HOME to an earlier version of Java. For example, one program I'm maintaining requires 32-bit Java 5 on OS X, so when using that program, I set JAVA_HOME by running:
export JAVA_HOME=$(/usr/libexec/java_home -v 1.5)
For those of you who don't have java_home in your path add it like this.
sudo ln -s /System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands/java_home /usr/libexec/java_home
References:
Oracle explains the java_home command
An article for configuring the JDK in Spring Tool Suite (Eclipse
2019) on MacOS

Also, it`s interesting to set your PATH to reflect the JDK. After adding JAVA_HOME (which can be done with the example cited by 'mipadi'):
export JAVA_HOME=$(/usr/libexec/java_home)
Add also in ~/.profile:
export PATH=${JAVA_HOME}/bin:$PATH
P.S.: For OSX, I generally use .profile in the HOME dir instead of .bashrc

I am having MAC OS X(Sierra) 10.12.2.
I set JAVA_HOME to work on React Native(for Android apps) by following the following steps.
Open Terminal (Command+R, type Terminal, Hit ENTER).
Add the following lines to ~/.bash_profile.
export JAVA_HOME=$(/usr/libexec/java_home)
Now run the following command.
source ~/.bash_profile
You can check the exact value of JAVA_HOME by typing the following command.
echo $JAVA_HOME
The value(output) returned will be something like below.
/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home
That's it.

I'm on Mac OS 10.6.8
The easiest solution works for me is simply put in
$ export JAVA_HOME=$(/usr/libexec/java_home)
To test whether it works, put in
$ echo $JAVA_HOME
it shows
/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
you can also test
$ which java

Nowadays Java seems to be installed in /Library/Java/JavaVirtualMachines

I tend to use /Library/Java/Home. The way the preferences pane works this should be up to date with your preferred version.

That above works not any more in YOSEMITE for GRAPHICAL APPLICATIONS! Like eclipse, or anything started with Spotlight. (.bash_profile, launchd.conf works for terminal sessions only.)
Before starting eclipse, just open a terminal window, and give out the following command:
launchctl setenv JAVA_HOME /Library/Java/JavaVirtualMachines/jdk1.7.0_45.jdk/Contents/Home
(With your installation path! Perhaps works with $(/usr/libexec/java_home) instead of the full path too.)
View the whole excellent article about the permanent solution here:
Setting environment variables via launchd.conf no longer works in OS X Yosemite/El Capitan/macOS Sierra?

It is recommended to check default terminal shell before set JAVA_HOME environment variable, via following commands:
$ echo $SHELL
/bin/bash
If your default terminal is /bin/bash (Bash), then you should use #hygull method
If your default terminal is /bin/zsh (Z Shell), then you should set these environment variable in ~/.zshenv file with following contents:
export JAVA_HOME="$(/usr/libexec/java_home)"
Similarly, any other terminal type not mentioned above, you should set environment variable in its respective terminal env file.
This method tested working in macOS Mojave Version 10.14.6.

I've found this stack to help, i was having the same issue and i could fix:
My java path was here:
/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home
and was needed to put into my .bash_profile:
export JAVA_HOME=\"/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home\"
Hope help

As other answers note, the correct way to find the Java home directory is to use /usr/libexec/java_home.
The official documentation for this is in Apple's Technical Q&A QA1170: Important Java Directories on OS X: https://developer.apple.com/library/mac/qa/qa1170/_index.html

For me maven seems to work off the .mavenrc file:
echo "export JAVA_HOME=$(/usr/libexec/java_home -v 1.8)" > ~/.mavenrc
I'm sure I picked it up on SO too, just can't remember where.

Create file ~/.mavenrc
then paste this into the file
export JAVA_HOME=$(/usr/libexec/java_home)
test
mvn -v

Skipping Terminal setup since you mentioned applications, permanent system environment variable set up (works for macOS Sierra; should work for El Capitan too):
launchctl setenv JAVA_HOME $(/usr/libexec/java_home -v 1.8)
(this will set JAVA_HOME to the latest 1.8 JDK, chances are you have gone through serveral updates e.g. javac 1.8.0_101, javac 1.8.0_131)
Of course, change 1.8 to 1.7 or 1.6 (really?) to suit your need and your system

For Fish Shell users, use something like the following: alias java7 "set -gx JAVA_HOME (/usr/libexec/java_home -v1.7)"