Develop Reference

Where to install JDK .tar.gz file on Ubuntu 18.04?

Where is the recommended place to install the jdk .tar.gz file I just downloaded? I want it to be available for all users.
The installation guides that I have found told me to extract the jdk in many different places, such as /opt, /usr/lib and /usr/local. But the which one is the "right" choice? Why?

Into /usr/lib/jvm/ folder, the reason is because the default installation path is that one when you use the sudo apt install command, which makes total sense to me.
Example:
OpenJDK 11 is located at : /usr/lib/jvm/java-11-openjdk-amd64/bin/java
OpenJDK 8 is located at : /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java
For more information, you can read this article here.

First Download the Oracle JDK Download Oracle JDK or Open JdkDownload Open JDK, then follow these commands :
First Unzip the tar file with this following command
tar zxvf <tar file name>
Like : tar zxvf jdk-11.0.2.jdk
enter your password if asked
Now set the JAVA_HOME i.e system variables to the end of /etc/profile file
first, open /etc/profile : vi /etc/profile
and press I to insert and put this at the end
export JAVA_HOME=<Directory where JAVA has been extracted>
export JAVA_HOME=/home/jdk-10.0.2.jdk/Contents/Home
export PATH=$PATH:$JAVA_HOME/bin
now press ESC + SHIFT + :WQ to save the changes

For installation from the JDK tar.gz use the following command to unpack the tarball to the desired directory where you need to install java :
tar zxvf jre-8u73-linux-x64.tar.gz
Then you can set the java home by editing the environment file and set java home like :
JAVA_HOME="/usr/lib/jvm/java-8-openjdk-amd64"
where the latter part is the directory in which you have installed java.Usually java will be installed in the /usr/lib/ .Use an editor like nano or vim to edit the file and add the above key value to set java home.

Error: JAVA_HOME is set to an invalid directory: /usr/lib/jvm/java-8-oracle/jre/bin/java when i run gradle command in terminal

I am working in Ubuntu 16.04. I need to install gradle and the gradle is installed when i checked with sudo apt list --installed command but when i use gradle -version command it shows the following error,
JAVA_HOME is set to an invalid directory: /usr/lib/jvm/java-8-oracle/jre/bin/java
In sudo vim /etc/environment file,
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games"
JAVA_HOME="/usr/lib/jvm/java-8-openjdk-amd64/"
http_proxy="http://username:password#IP:port no/"
https_proxy="https://IP:port no/"
ftp_proxy="ftp://IP:port no/"
I don't know where i made mistakes. Please help me.
Thanks.

On a 64bit openSuse 64 42.1 box;
readlink -f $(which java)
provided;
/usr/lib64/jvm/java-1.8.0-openjdk-1.8.0/jre/bin/java
But;
export JAVA_HOME=/usr/lib64/jvm/jre-1.8.0-openjdk
is the path that worked and allowed java emulator to run.
So i think we have to manually browse our file system and see what path to choose.

Today I faced this problem. I am using the default java that comes with your linux distro (so in my case, linux mint).
$ whereis java
This command gave me
java: /usr/bin/java /usr/share/java
So, I opened /user/bin. There was a link to Java. I right clicked it and selected follow original link. This lead me to /usr/lib/jvm/java-11-openjdk-amd64/bin/java.
So now that I know where this java is, I opened my .bashrc file, and edited the JAVA_HOME.
So for my case,
## My Custom variables
export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64
export PATH=$JAVA_HOME/bin:$PATH
This solved the problem.
Now if you are using some other java (say you downloaded from oracle and extracted the zip file ...), then you have to add that location. So for example, if your java is in /home/user/.sdkman/candidates/java/current, then
export JAVA_HOME=/home/user/.sdkman/candidates/java/current
export PATH=$JAVA_HOME/bin:$PATH

I see a mismatch. In your enviornment file the JAVA_HOME is set to "/usr/lib/jvm/java-8-openjdk-amd64/" and your mentioned that the error that you got relates to the JAVA_HOME as "/usr/lib/jvm/java-8-oracle/jre/bin/java"
If you JAVA is really installed in /usr/lib/jvm/java-8-oracle directory, then you need to ensure that the JAVA_HOME is set to that directory. And also your PATH reflects $JAVA_HOME/bin in it.
I typically install Oracle JDK/JRE separately in a separate directory such as /usr/local/jdk1.8.0 etc.

check the jvm installtion folder from Files
eg : /usr/lib/jvm/java-12-oracle
then in terminal run sudo nano /etc/environment and add the line
JAVA_HOME="/usr/lib/jvm/java-12-oracle"
Then open terminal and run
export JAVA_HOME="/usr/lib/jvm/java-12-oracle"

How to set JAVA_HOME environment variable on Mac OS X 10.9?

I just purchased a brand new MacBook Pro.
This is my first MAC ever and I'm still trying to get the hang of navigating my way around.
Anyway, I'm also new to Java and I've been practicing on my Windows PC before it permanently died.
Now that I'm on this MAC, I installed my JDK and now I need to set the JAVA_HOME environment variable.
I have no idea what to do.
I tried following some of these guides and didn't get very far.
Mkyong.com : How to set JAVA_HOME variable in Mac OSX
YouTube : How to set environment variables on mac, linux, solaris, rhel
YouTube : How to Set Environment Variables in Mac
I was able to locate the terminal and I think I created some multiple files. I'm getting messages like this:
(1) Another program may be editing the same file.
If this is the case, be careful not to end up with two
different instances of the same file when making changes.
Quit, or continue with caution.
(2) An edit session for this file crashed.
If this is the case, use ":recover" or "vim -r /Users/Erwin/.bash_profile"
to recover the changes (see ":help recovery").
If you did this already, delete the swap file "/Users/Erwin/.bash_profile.sw p"
to avoid this message.
Can somebody tell how to set Java in Mac OSX environment step by step?

If you're using bash, all you have to do is:
echo export "JAVA_HOME=\$(/usr/libexec/java_home)" >> ~/.bash_profile
If you're using zsh (which probably means you're running macOS Catalina or newer), then it should instead be:
echo export "JAVA_HOME=\$(/usr/libexec/java_home)" >> ~/.zshrc
In either case, restart your shell.
If you have multiple JDK versions installed and you want it to be a specific one, you can use the -v flag to java_home like so:
echo export "JAVA_HOME=\$(/usr/libexec/java_home -v 1.7)" >> ~/.bash_profile

I just spent 2 hours setting this variable. The other answers did not work properly for me. I'm using macOS Catalina 10.15.4.
First, find your actual Java SDK Home directory:
/usr/libexec/java_home
Manually navigate there to make sure you don't have any mistakes due to incorrect versions, etc. For me, this was:
/Library/Java/JavaVirtualMachines/jdk-13.0.2.jdk/Contents/Home
Next, edit your terminal's profile. If you're using zsh, this will be:
vim ~/.zshrc
If you're not using zsh, this will be:
vim ~/.bash_profile
Inside, add the following new line anywhere in the file:
export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-13.0.2.jdk/Contents/Home
Restart your terminal app (or source ~/.bash_profile), and it should work properly.

I did it by putting
export JAVA_HOME=`/usr/libexec/java_home`
(backtics) in my .bashrc. See my comment on Adrian's answer.

Set $JAVA_HOME environment variable on latest or older Mac OSX.
Download & Install install JDK
First, install JDK
Open terminal check java version
$ java -version
Set JAVA_HOME environment variable
Open .zprofile file
$ open -t .zprofile
Or create . zprofile file
$ open -t .zprofile
write in .zprofile
export JAVA_HOME=$(/usr/libexec/java_home)
Save .zprofile and close the bash file & then write in the terminal for work perfectly.
$ source .zprofile
Setup test in terminal
$ echo $JAVA_HOME
/Library/Java/JavaVirtualMachines/jdk-13.0.1.jdk/Contents/Home

In Mac OSX 10.5 or later, Apple recommends to set the $JAVA_HOME variable to /usr/libexec/java_home, just export $JAVA_HOME in file ~/. bash_profile or ~/.profile.
Open the terminal and run the below command.
$ vim .bash_profile
export JAVA_HOME=$(/usr/libexec/java_home)
save and exit from vim editor, then run the source command on .bash_profile
$ source .bash_profile
$ echo $JAVA_HOME
/Library/Java/JavaVirtualMachines/1.7.0.jdk/Contents/Home

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

If you are using Zsh, then try to add this line in ~/.zshrc file & restart terminal.
export JAVA_HOME=$(/usr/libexec/java_home)

I got it working by adding to ~/.profile. Somehow after updating to El Capitan beta, it didnt work even though JAVA_HOME was defined in .bash_profile.
If there are any El Capitan beta users, try adding to .profile

Since I'm using openjdk managed with sdkman, I added
sudo ln -sfn /path/to/my/installed/jdk/openjdk.jdk /Library/Java/JavaVirtualMachines/openjdk.jdk
Adding this to your system lets java_home recognize your installed version of Java even when its not installed via standard packages

I checked my /Library/Java/JavaVirtualMachines/
directory and found the version to be jdk1.8.0_321.jdk/Contents/Home
and added this directly to my .bash_profile:
export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_321.jdk/Contents/Home
but it's still complaining after sourcing the .bash_profile:The operation couldn’t be completed. Unable to locate a Java Runtime that supports apt.

In the latest Mac, you have to add the Set $JAVA_HOME environment variable in .zprofile. Here, we simple way to open it. Press ⌘ + Shift + . from keyboard. Just open it and add the $JAVA_HOME environment variable as explained here:

JAVA 11 via Homebrew - tested on macos Ventura 2022
.zshrc
export JAVA_HOME=/opt/homebrew/opt/openjdk#11/libexec/openjdk.jdk/Contents/Home

For Mac M1
Download & Install install JDK
Open terminal check java version
java -version
Now create a file
touch .zprofile
Open the file
open -t .zprofile
Add the below line
export JAVA_HOME=$(/usr/libexec/java_home)

I resolved it on macOS Monterey by using the option provided by Google
Under Gradle JDK, choose the Embedded JDK option.
https://developer.android.com/studio/intro/studio-config#:~:text=A%20copy%20of%20the%20latest,use%20for%20your%20Android%20projects.

I'm able to solve this issue by setting JAVA_HOME in .bash_profile file
export JAVA_HOME=/usr/local/opt/openjdk#17
Note:
I installed openjdk version 17 using 'brew'. I got this location from brew console. I'm using 'bash' instead of 'zsh' in my mac.

Open Terminal.
Confirm you have JDK by typing “which java”. ...
Check you have the needed version of Java, by typing
“java -version”.
Set JAVA_HOME using this command in Terminal: export
JAVA_HOME=/Library/Java/Home.
echo $JAVA_HOME on Terminal to confirm
the path.

More simply on a mac terminal with a modern OSX
$ vim ~/.zshrc
Type "a" to being editing, and then paste (ctrl + v):
$ JAVA_HOME=/usr/libexec/java_home
then hit "escape" and type exactly ":wq" in order to write to the file and quit vim mode.
Finally, when out of vim mode and back in your terminal, type
$ source ~/.zshrc
This will refresh so that your terminal is aware of the changes.
IMPORTANT * If you don't "source" the file, you won't see the changes in this terminal session.
Check the changes by typing
$ echo $JAVA_HOME
and you should see /usr/libexec/java_home

Quick Guide for M1
Add java sdk into your m1
check version
java --version
Get all java versions installed in ur mac
/usr/libexec/java_home -V
Execute for Java path from library
/usr/libexec/java_home
(specify java version if you have multiple version, In my case -v17.0.5
/usr/libexec/java_home -v17.0.5
Mac>User>'YourUserName/Home'>.zshrc
export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-17.0.5.jdk/Contents/Home

how to run jar file on RHEL5?

I have made a jar file which i tested in windows and it works fine. now i want to test it for red hat enterprise linux 5. but i dont know how to run jar files in rhel5.
i've tried java -jar My.jar but it says bash: java: command not found. i've set JAVA_HOME variable as export JAVA_HOME=/root/jdk1.6.0_21 but still not working.
can anybody tell me how to run jar file in rhel5?

You need to set PATH variable , something like
export PATH=$PATH:/usr/java/jdk1.5.0_07/bin
replace /usr/java/jdk1.5.0_07/bin with path to your jdk's bin directory.
The problem is your terminal tries to find java command from the PATH , but it couldn't find it.
Update:
You need to setup global config in /etc/profile OR /etc/bash.bashrc file for all users:
# vi /etc/profile
Next setup PATH / JAVA_PATH variables as follows:
export PATH=$PATH:/usr/java/jdk1.5.0_07/bin
export PATH=$PATH:/usr/java/jdk1.5.0_07/bin

Top tip but slightly off topic.
1) Install your JDK in /usr/local/jdkX.X.X_XX/
2) Create a symbolic link /usr/local/java -> your chosen JDK installation
When you install new versions of java or if you want to revert to an older version, just change the symbolic link.

How to install Apache Ant?

I want to install SMSlib (http://smslib.org/) in installation instruction (http://code.google.com/p/smslib/wiki/Installation).
In here I must install Apache Ant, but I didn't understand how to do that.
I already download Apache Ant 1.7.1 , read manual (http://ant.apache.org/manual/index.html)
In here I must have RPM version from jpackage.org right? I already go to http://www.jpackage.org/ after that what must I do? I already try (http://mirrors.dotsrc.org/jpackage/1.7/generic/free/repodata/) and (http://www.jpackage.org/browser/browse.php?jppversion=1.7) but too many link. I don't know witch one must I download

If you're on Windows, you can use WinAnt, a Windows installer for Apache Ant that I made.

Step 1: Download and install
Download Ant. Go to the Ant homepage and click to download the binary. Because we’re talking about Windows, choose to download the ZIP file rather than any of the others. Scroll down to where it says “Current release of Ant” and click on the ZIP filename.
Once downloaded, unzip the file. You’ll now need to choose a permanent home for Ant on the computer. c:\java\ant is often used, but you can put it wherever you want.
Step 2: Set environment variables
For Windows XP: To set environment variables on Windows XP, right click on My Computer and select Properties. Then go to the Advanced tab and click the Environment Variables button at the bottom.
For Windows 7: To set environment variables on Windows 7, right click on Computer and select Properties. Click on Advanced System Settings and click the Environment Variables button at the bottom.
The only environment variable that you absolutely need is JAVA_HOME, which tells Ant the location of your JRE.
If you’ve installed the JDK, this is likely
c:\Program Files\Java\jdk1.x.x\jre
on Windows XP and
c:\Program Files(x86)\Java\jdk1.x.x\jre
on Windows 7. You’ll note that both have spaces in their paths, which causes a problem. You need to use the mangled name[3] instead of the complete name. So for Windows XP, use C:\Progra~1\Java\jdk1.x.x\jre and for Windows 7, use C:\Progra~2\Java\jdk1.6.0_26\jre if it’s installed in the Program Files(x86) folder
That alone is enough to get Ant to work, but for convenience, it’s a good idea to add the Ant binary path to the PATH variable.
This variable is a semicolon-delimited list of directories to search for executables. To be able to run ant in any directory, Windows needs to know both the location for the ant binary and for the java binary. You’ll need to add both of these to the end of the PATH variable. For Windows XP, you’ll likely add something like this:
;c:\java\ant\bin;C:\Progra~1\Java\jdk1.x.x\jre\bin
For Windows 7, it will look something like this:
;c:\java\ant\bin;C:\Progra~2\Java\jdk1.x.x\jre\bin
Done
Once you’ve done that and applied the changes, you’ll need to open a new command prompt to see if the variables are set properly. You should be able to simply run ant and see something like this:
Buildfile: build.xml does not exist!
Build failed
That means Ant is installed properly and is looking for a build.xml file.
Source: http://www.nczonline.net/blog/2012/04/12/how-to-install-apache-ant-on-windows/

You can follow these instrunctions-
1)Download the latest version of ant from http://ant.apache.org/bindownload.cgi
2)Unzip and save it to your C:\ directory as ant.
3)Add the bin directory to your PATH environment variable.
4)Add the ANT_HOME environment variable set to C:\ant.
you can use following commands to set ANT_HOME variable
C:>set ANT_HOME=C:\ant
C:>set JAVA_HOME=C:\jdk
C:>set PATH=%ANT_HOME%\bin;%JAVA_HOME%\bin
C:>ant -version
Apache Ant version 1.8.1 compiled on April 30 2010
if you have java installed on your machine
5)Add the ANT_OPTS environment variable set to -Xmx256M.
This is all you need to install ant on your machine.

1) Download "apache-ant-1.8.4-bin.zip" from "http://ant.apache.org/bindownload.cgi"
2) Unzip it and copy "apache-ant-1.8.4" in "c:\Program Files"
3) Right Click "My Computer" -> properties -> Advanced -> Environment variables -> Edit variable "PATH" and append value "C:\Program Files\Java\jdk 1.7.0_04\bin;C:\Program Files\apache-ant-1.8.4\bin" and Click "OK".
4) open cmd and type "ant" for checking.

the installation of ant and smslib is pretty simple. All you need to do is extract it to some directory. Export the path in case of Linux or set the ANT_HOME\bin to the PATH variable to access it from any directory in the shell. ANT_HOME is the root directory where ant is installed.
For SMSLib Download the zip file and this link should guide you on a step by step basis

Sound's like you're using Linux. If so, the easiest way would be to use a package management frontend like Synaptic and install ant in there.

Its very simple just install Apache ant installer for windows give on [link][1]
[1]: http://code.google.com/p/winant/ and all is set.No need to set Environment variables.It will automatically do every thing for you.

You can install Apache Ant with only single command on Ubuntu:
sudo apt install ant
Check the version of ant installed with:
ant -version