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Change system Java

I have 3 java in my system 1.6, 1.7 and java 8.
I set my JAVA_HOME and path to 1.7, but when I run java -version using cmd administrator mode it return me 8.
Could anyone please tell me from where cmd pick java, and how i can change it to another version.
Updated: I already set java 7/bin in path variable

Start your cmd shell and type echo %PATH%.
OS would inspect listed directories and the first one that has java binary will be the one being used.
To change it - the PATH variable is set based on the settings in Control Panel -> System -> Advanced System Settings -> Environment Variables. You'd need to start a new cmd session to see updated changes.

When we run cmd as an administrator then it pick java.exe which is already available under C:/user/windows32 folder.
To resolve this issue, instead of appending my java at the end of the path, append in the starting of the path vaiable.
So here is the code used in cmd if run as administrator
set path=%JAVA_HOME%/bin;%path%;
java -version

Java won't compile

I have been getting an error when I try to compile my Java code.
'javac' is not recognized as an internal or external command, operable program or batch file.
My directory looks like this: Computer -> OS(C:) -> Program Files -> Java -> jdk1.8.0_60 -> Bin
When I type set path into CMD I get this: Path=file:///C:/Program%20Files/Java/jdk1.8.0_60/bin
My question is: Why isn't javac being recognized even after I have changed the path?
C:\Program Files (x86)\Java\jdk1.8.0_11\bin;

Note that your java is in Program Files (x86) not Program Files.
You should set path like this,
set path=C:\Program Files (x86)\Java\jdk1.8.0_11\bin
echo %path%
Moreover it will not set the path forever once you close the cmd the path you has set will just vanish. If you want to store the path in your system you should add your path to system's environment variable. You may find this helpful for adding environment variable.

First of all check whether your system is 64-bit or 32-bit windows. If it is 32-bit you are doing fine but if it is 64-bit you need to download 64-bit version of jdk and when you install it the java bin should be available in program files not in program files(x86) then set the path from there.

'javac' is not recognized as an internal or external command

I have to convert my Matlab algorithm in Java. For this I'm using matlab builder ja toolbox, after following all the necessary steps, the build fails and this error is displayed:
'javac' is not recognized as an internal or external command, operable program or batch file. Error: An error occurred while shelling out to javac (error code = 1). Unable to build executable.
When typing java -version in the matlab command line, this is what i get:
Java 1.6.0_12-b04 with Sun Microsystems Inc. Java HotSpot(TM) Client VM mixed mode
It means I should have this compiler of java installed on my computer, only then the matlab builder ja works. I'm new to Java, I'm not sure what compiler I should be looking for.

First make sure you have installed jdk and jre, both are installed with the java software development kit. The installation folder is typically C:\Program Files\Java.
Now go to Computer > Properties > Advanced system settings in the advanced tab click on Environment Variables
In System variables find the variable named Path, in the value of Path you will find a java path like C:\ProgramData\Oracle\Java\javapath, just change it to C:\Program Files\Java\jdk1.x.x_x\bin.
Hope that helps.

If you want javac (the compiler), you'll need to download the Java Development Kit (JDK), not just the Java Runtime Environment (JRE). Note that the JDK includes a JRE.
This tutorial give instructions to install JDK to your computer.

You need to make sure that Java SDK is installed and also PATH is set properly so that windows would be able to know where the executable is. Detailed steps on how to debug this issue is explained here: http://www.windows-commandline.com/javac-not-recognized-internal-external-command/

To solve the aforementioned problem follow the mentioned steps:
1) Copy the address location of your Java\jdk\bin folder usually installed in your C: drive. It should look something like this:
C:\Program Files (x86)\Java\jdk1.8.0_65\bin
2) Right click on My Computer-->Properties-->Change settings-->
Advanced-->Environment Variables.. -->New..
3) Now,
Set Variable name: PATH
Variable value: C:\Program Files (x86)\Java\jdk1.8.0_65\bin
4) Press OK, re-open your cmd and compile your program.
Hopefully it worked!

Path is defined as the filename. Ex, C://aklsej;dlfkj/blahblah
You will need to specify the full path in the system control panel, advanced system settings, edit variables, edit path, put a semicolon after the last entry and don't delete anything, and then add the full path wherever you installed java to.
to make this easy, do a search for javac in the search panel and then just add the full path to the environmental variables from there.

Set Following Environment Variables
It will works
JAVA_HOME=C:\Program Files\Java\jdk1.7.0_09
set PATH=%JAVA_HOME%\bin

Download Java from given link according to your requirements.
http://www.oracle.com/technetwork/java/javase/downloads/index.html
then follow below steps:
Step-1 : Right Click on MyComputer and click on properties .
Step 2 : Click on Advanced tab
Step 3 : Click on Environment Variables
Step 4 : Create a new class path for JAVA_HOME
Step 5 : Enter the Variable name as JAVA_HOME and the value to your jdk bin path ie c:\Programfiles\Java\jdk-1.6\bin and
NOTE Make sure u start with .; in the Value so that it doesn't corrupt the other environment variables which is already set.
Step 6 : Follow the Above step and edit the Path in System Variables add the following ;c:\Programfiles\Java\jdk-1.6\bin in the value column.
Step 7 :Your are done setting up your environment variables for your Java , In order to test it go to command prompt and type
java
who will get a list of help doc
In order make sure whether compiler is setup Type in cmd
javac
who will get a list related to javac
Hope this Helps !

If you receive this error, Windows cannot find the compiler (javac).
Here's one way to tell Windows where to find javac. Suppose you installed the JDK in C:\jdk1.8.0. At the prompt you would type the following command and press Enter:
C:\jdk1.8.0\bin\javac HelloWorld.java
If you choose this option, you'll have to precede your javac and java commands with C:\jdk1.8.0\bin\ each time you compile or run a program. To avoid this extra typing, consult the lecture "Creating a Hello World application" in this website
Class names, 'HelloWorld', are only accepted if annotation processing is explicitly requested
If you receive this error, you forgot to include the .java suffix when compiling the program. Remember, the command is javac HelloWorld.java not javac HelloWorld.

Set default classpath to use in `java` command in command prompt

What I'm trying to do is running a .java source by compiling and running it from command prompt (not using any IDE) using commands javac and java and the program connects with MySQL, so everytime I run the program from cmd, I need to specify path of the MySQL connector using -classpath switch of java. And entire command to run the program gets something like below:
java -class .;path/to/connector/mysql-connector.jar MySQLConnect
where I want it to be as simple as for other programs like java MySQLConnect
and it should run the program.
Is there any way I can add the connector's path to environment variables of Windows that java make use of it. I already tried by creating a new CLASSPATH variable in Windows environment variables and added absolute path of the connector with file name along, but that didn't worked.
Please provide me the workaround of this Windows and Ubuntu as well.
Thanks.

WIndows : Copy mysql-connector.jar to C:\Program Files\Java\jdk1.6.0\jre\lib\ext
and copy the same file to C:\Program Files\Java\jre1.6.0\lib\ext
go to My Computer -> Properties -> Advanced -> Environment Variables
Set these paths
JAVA_HOME
C:\Program Files\Java\jdk1.6.0
PATH
C:\Program Files\Java\jdk1.6.0\bin;
CLASSPATH
.;C:\Program Files\Java\jre1.6.0\lib\ext\mysql-connector.jar;.;
open a fresh command propmpt
type
java -version press Enter

WINDOWS
Go to My Computer -> Properties -> Advanced -> Environment Variables
then find CLASSPATH variable in System variables and click on edit to add your jar file there.
LINUX or MAC
In your shell use a variable CLASSPATH in your .bashrc or .profile to set a default class path.

Set classpath=%classpath%;location of mysql-connector with connector file name.jar. For example:
set classpath=%classpath%;D:\TECHNICAL\JAVA WORLD\JDBC\mysql-connector-java-5.1.18-bin.jar;
D:\TECHNICAL\JAVA WORLD\JDBC\ is the location of mysql-connector.
To set this path go to Advanced System Settings->Environment variables->User variables->CLASSPATH->Edit, then type set classpath=%classpath%;D:\TECHNICAL\JAVA WORLD\JDBC\mysql-connector-java-5.1.18-bin.jar; and finally press OK.
I have done in this style. After that, I got result of programs correctly. Then there is noCLassNotFoundException.

"java -version" not working in command prompt

I downloaded this Java JDK and installed it.
But when I go to the command prompt to check the version, it says it's not recognized.
Is anyone else experiencing this issue with the latest Java?
I might not have installed the right version. I need the java that works with grails
C:\>java
'java' is not recognized as an internal or external command,
operable program or batch file.
C:\>java -version
'java' is not recognized as an internal or external command,
operable program or batch file.
C:\>
when i do a search on my computer for java, it does not find anything

Windows 2k8 R2 server-
For both java [-option] or %JAVA_HOME% to work in the command line you need the following:
In Control Panel->System and Security->System->Advanced system setting->Advanced->Environment Variables->System Variables
Edit the Path variable and add a ";" after the last value and add the the path to the Java bin directory:
e.g.- C:\Progra~2\Java\jre6\bin\
Add the JAVA_HOME Variable with the value set to the path for the java executable:
e.g.- C:\Progra~2\Java\jre6\bin\java.exe

Press simultaneously the "windows" and "pause" buttons on your keyboard, this will bring up the System Preferences dialog.
In the Advanced tab, find Environment Variables.
Then, in the User (upper) section, create or update the following two variables :
JAVA_HOME = where you put your JDK, eg. C:/Java/SDK
PATH = %JAVA_HOME%/bin
Close the dialogs.
Then, in a new command-line console, try "javac -version" and see if it's detected.
It's important that you use a new console, because environment variables are read only when the console is launched.

Java is typically installed (on Windows) as C:\Program Files\Java\jdk<version>
That installation directory has a subdirectory bin which you need to append to your PATH environment variable via the control panel. Then, the commands like java, javac etc. will be available on the command line.
BTW, the same is true for Grails.

Is the -version flag not recognized, or is the "java" command not recognized? One way to test this is just to type 'java' by itself and run it and see what happens.
If the command is not recognized, make sure that the JDK's install path is in your windows PATH. If not, you won't be able to use any of the java executables from the command prompt. Here's another link that may help out.

You need to manually add the path to javac.exe and java.exe to your operating system path. The Java installation program doesn't do that for you.

You most likely don't have java.exe in your system's PATH variable.

For Linux:
check $PATH and $JAVA_HOME. You can configure it in /etc/environment
From console you can check it like:
$ echo $PATH
For Windows:
My Computer -> Properties -> Advanced -> Environment Variables
Check there PATH.
From console you can check it like:
echo %PATH%

You should have a Java icon in Windows Control Panel. Locate the Java tab and click the View button. That will show you the path to the Java executables.
Last but not least, make sure you have restarted the computer so changes in the PATH variable can take effect.

You installed the JDK. Isn't java.exe part of the JRE? Do you have that installed?

Maybe your system variables in the environment variables are not set properly. Follow the steps in the link below. Finally, make sure the path component in system variables has only one JDK path. Delete other JDK paths that you won't use.
https://docs.oracle.com/javase/tutorial/essential/environment/paths.html

You might have installed a previous or older version of Java so you can just uninstall it and directly download JDK from Java JDK
I was also facing the same issue but when I downloaded and installed the latest version the issue was resolved.
Also uninstall any other Java versions which may be present in the program files.
To get to know other versions which may be present in your computer use Windows File Explorer to go to:
Files > Windows C > Program Files > Java
All the JDK and JRE you have will be listed there. Uninstall any other Java versions other than what you installed. And then make sure you have set the path variable of the JDK.

For me, it was incorrect line in the PATH
(1) Check PATH: Type "Edit System Environment Variables" on the search -> System Properties -> Advance -> Environment Variables -> System variables -> Path
(2) On the list, mine was C:\Program Files (x86)\Common Files\Oracle\Java\javapath so I just add \ at the end (the exe files in the javapath folder)
OS: Windows 10 64 bit

IF you set the PATH and it's not showing up in cmd when you run %PATH%, try restarting your computer.