Develop Reference

Run a jar file only with jre [duplicate]

When trying to check the current version of Java in which I am running, I received the error "java is not recognized as an internal or external command, operable program or batch file.".
I am running Windows 7 OS and have downloaded the latest JDK and felt I may have accidentally deleted the java from machine as before I was able to check the Java version using the command "java -version".
What software must I download to get Java working on my machine again?
EDIT:
I have managed to get Java running from my cmd again after ensuring all environment variables pointed to the current Java SDK.

You need to configure your environment variables, JAVA_HOME and PATH.
JAVA_HOME must contain the path to java, and you should add %JAVA_HOME%\bin to PATH
Alternatively, you can simply add to your PATH the whole path to the bin folder, without the JAVA_HOME variable, however, this makes a little more annoying when you need to have more than one java version on your machine (that way you only need to change JAVA_HOME and don't even bother with PATH)

For Windows 7:
Right click on My Computer
Select Properties
Select Advanced System Settings
Select the Advanced tab
Select Environment Variables
Select Path under System Variables
Click on the Edit button
In Variable value editor paste this at the start of the line
C:\Program Files\Java\jdk1.7.0_72\bin;
Click Ok then Ok again
Restart command prompt otherwise it won't see the change to the path variable
Type java -version in the command prompt.
Notes on Step 8:
The version of java in this may be different from the one used here -- this is only an example.
There will probably be other values in the path variable. It is really important that you don't delete what's already there. That's why the instructions say to paste the given value at the start of the line -- this means that you don't remove the existing value, you just put java before it. This also fixes any problems you'd be getting if an other version of java is also on the path.
Notes on Step 6:
This sets the path for the computer, not for the individual user. It may be that you're working on a computer which other developers also use, in which case you'd rather set the user variables, rather than the system variables

It sounds like you haven't added the right directory to your path.
First find out which directory you've installed Java in. For example, on my box it's in C:\Program Files\java\jdk1.7.0_111. Once you've found it, try running it directly. For example:
c:\> "c:\Program Files\java\jdk1.7.0_11\bin\java" -version
Once you've definitely got the right version, add the bin directory to your PATH environment variable.
Note that you don't need a JAVA_HOME environment variable, and haven't for some time. Some tools may use it - and if you're using one of those, then sure, set it - but if you're just using (say) Eclipse and the command-line java/javac tools, you're fine without it.
1 Yes, this has reminded me that I need to update...

Assume, Java/JDK is installed to the folder: C:\Program Files\Java:
Follow the steps:
Goto Control Panel → System → Advanced system settings → Advanced → Environment variables (Win+Pause/Break for System in Control Panel)
In the System variables section click on New…
In Variable name write: JAVA_HOME
In Variable value write: C:\Program Files\Java\bin, press OK:
In the System variables section double click on Path
Press New and write C:\Program Files\Java\bin, press OK:
In Environment variables window press OK
Restart/Run cmd.exe and write: java --version:

Search environment variables.
open the "edit the system environment variables".
then click on "environment variables".
Under "User variables" click on "Path" then "Edit".
Find your Java path and click "Edit".
then paste the path of your java installation folder.
Mostly you can find it on a path similar to this.
C:\Program Files\Java\jdk-12.0.2\bin
Then click OK.
now in the start menu, type cmd.
open the command prompt.
type
java -version
If you did it right,it should show something like this.

For me its start working after putting ,: in the starting of the system variable path :--

My solution was to put same value (path to JDK bin folder) in JAVA_HOME and Path

In my case, PATH was properly SET but PATHEXT has been cleared by me by mistake with .exe extension. That why window can't find java or anything .exe application from command prompt. Hope it can help someone.

This problem is on Windows 8.
First copy your Path of java jdk - e.g. C:\Program Files\Java\jdk1.7.0_51\bin.
Right on the My Computer Icon on the Desktop and Click Properties.
Select 'Advanced System Settings' in the left pane.
Under 'Advanced' tab, select 'Environment Variables' at the bottom.
In System Variables, select 'Path' Variable and edit it.
Paste the path and add a ';' at the end - e.g. C:\Program Files\Java\jdk1.7.0_51\bin;

I had the same problem. Just Install the exact bit of java as of your computer. If your PC is 64 bit then install 64 bit java. If it is 32 bit then vice versa :)

Not sure why, but in my case, the reason was because I was running Anaconda terminal instead of the CMD.
After I use CMD and update the path settings as mentioned by all comments above the issue solved on my side.

In case you are using a laptop and do not have the Pause\Break button.
For windows 10 users with 20h2 and above:
1 WIN → type "About your PC" → scroll at the bottom → Advanced system settings → Environment variables or WIN+R → shell:::{bb06c0e4-d293-4f75-8a90-cb05b6477eee} to open Classic System Properties → on the left side → Advanced system settings → Environment variables
Also for Windows 10 and Windows 7:
1 WIN → This PC → properties → Advanced system settings → Environment variables
In the System variables section click on New…
In Variable name write: JAVA_HOME
In Variable value write: C:\Program Files\Java\jdk-15.0.2\bin, press OK
I have taken steps 2-4 from Vijay Bhatt
There is a bit faster way to set a system variable. Run a console (terminal) as an administrator.
General command synax to add a new variable:
setx variableName value /M
In our example, we would need to set it as
setx JAVA_HOME "C:\Program Files\Java\jdk-15.0.2\bin" /M`
Like this:
/M - flag specifies to set the variable in the system environment.
After command execution, you should see the message:
SUCCESS: Specified value was saved.
How can I check that it is added?
Close your active terminal;
Open your favorite terminal;
Type java -version.
You should see something similar to this:
Notice:
User variables can be created w/o having a root (administrator privileges), whereas to create System variable; You need to open a console as a root.
I have used C:\Program Files\Java\jdk-15.0.2\bin as an example, in your case, it could be different from mine.

I opened a new command prompt in Windows 10 after updating the environment variables without closing the old one(To have my commands handy and lazy to type again)
Still, the new cmd window was referring to the previous version of Java.
Then once I closed the all cmd prompts that ran with admin privileges, the new java version was getting reflected.

I corrected my path variable but command prompt need to Restart otherwise, it won't be able to verify the change to the path variable. May be helpful for someone like me. so
"restart command prompt"

Restart the command prompt before checking the version of JDK installed. I spent 02 days on it until my problem resolved when I restarted the command prompt before checking javac - version, javac etc.

if you have cygwin installed in the Windows Box, or using UNIX Shell then
Issue bash#which java
This will tell you whether java is in your classpath or NOT.

If you have set the environment variables (JAVA_HOME and PATH) under user variables, command prompt (run as administrator) will not identify java. For that you need to set environment variables under system variables.

Try this:
System variables:
PATH = /bin folder of your jdk install
https://docs.oracle.com/javase/10/install/installation-jdk-and-jre-microsoft-windows-platforms.htm

Just some extra information for people that have still problems,
instead of editing the path variable of java, delete that part of the path(only the java!!)
and make a new variable pointing tpo the jdk/jre.
this seemed to work for me.

How to remove error Picked up _JAVA_OPTIONS: -Xmx512M?

In java program, When I try to compile some code it creates an error
I get this message:
Picked up _JAVA_OPTIONS: -Xmx512M
what type of error is this the page Suppressing the "Picked up _JAVA_OPTIONS" message cannot solve problem ,how to change system variable in windows 7 ??

Go to my computer and right click on top of that and click on properties, a new window will open like below.
then click on advanced system setting
then click on environment variable and delete _JAVA_OPTIONS from user variable
and then try again.

Part of my original answer was truncated, so here is the edited answer:
From the Start Buttong, search for System, then launch "System" from your search results. In the new window, select Advanced System Settings. A new window will open, select the Advanced tab, then click on the Environment button. In this new window, select _Java_Options, in the user variables and then click on Delete. If the lower section, System Variables, is greyed out and you cannot delete _Java_Options there, you will need to log on as an administrator, or attempt to run the "System" command as Administrator.

You have to delete your environment variable named "_JAVA_OPTIONS" going to system, advance settings. Save, close your project and restart.

Please check your JDK version. Maybe you need to change or upgrade your JDK version.

Unable to change system variable path in Windows 10 as an Admin

I am installing Java JDK in Windows 10 machine that requires registering its path by editing System Variables in Windows settings, but I tried both as an admin and regular user and it doesn't allow me to add the path, even copy paste or just adding any character.I have no trouble doing this in Win 8 until I am 'tempted' to avail and run free upgrade by Microsoft.
Q1:
Is this A bug in Windows 10? I update my machine regularly and also auto update is turned on to ensure to get the latest fix from Microsoft. Kaspersky is also disabled temporarily.
Q2:
How do you edit the system variable in Win 10 machine? I am planning to downgrade my Machine to windows 7 or 8 if this issue is not fixed.
Any ideas?

I was facing same issue.
When you search with "Environment Variable" you will get two result
Click on the second option "Edit the system environment variable"
"Environment Variable for your account" - This will only allow you to change "user variable". system variable will be disabled.
"Edit the system environment variable" - With this option you can change both (user & system variables). But once you click this link, you will get a popup where you need to click on "Environment Variables".

If you cant edit system variable under Path in windows 10, try this instead
Login as administrator
go to your Java folder e.g
C:\Program Files\Java\jdk8\bin and copy.
Now in search box beside windows logo at the bottom type
path
and select the one that says
'edit the system environment variables'
This is important, select 'New' tab in User variables for Administrator, not the 'New' tab from 'System variables' as you cant edit it.Now name it as you wish, mine is PATH.Now copy and paste the path where you installed Java, mine is under
c:\Program Files\Java\jdk8\bin
Hit ok to exit.
Restart your command line and test Java
java -version
it should tell you java version and Java is successfully installed and accessible.Start using it and cheers

When I was trying to add a new path to my system variables, I was unable to select the edit button. To get to system variables I went to my search bar and selected "edit environmental variables for your account." When i did this, the edit button was grayed out and I couldn't add a new path.
To fix this i typed in my search bar and selected "edit the system environment variables" once that box comes up right above the ok button select "click environmental variables". Yay, the path edit button is no longer grayed out. Hope this helps

I got around it by opening the System page in Control Panel (Win+X -> Y), going to "Advanced system settings", then clicking "Environment Variables". That properly launches the edit window and it works.

I also faced similar problem after installation of new JDK and following steps resolved the issue:-
Copy the entire content of path System variable in notepad and see
if there is any path related to Java.
Delete all the path related to Java.
Click Ok.
Now you can edit the Path without any issue.
If these steps doesn't work than you can create a new Variable.

My situation is a bit different as I use a small 7" windows tidy notebook called "one-notebook (One MIX)". It seems the "OK" key is not shown in the 2nd stage in horizontal position and you need to rotate the screen to see the OK. Spend a lunch time for that.

There is a simple solution if your global environment variables are disabled.
Follow these steps to open it in admin mode:
⊞ Win+X.
Y.
Search Advance System Settings and open it.
Now select environment variables.

Error: picked up java_options: -Djava.net.preferIPv4Stack=true

I get this error when doing anything in cmd involving Ionic and Android, e.g. Ionic build Android, or Ionic emulate Android etc... What does the error mean, is it important, and how do I fix it?

I'm pretty sure the _JAVA_OPTIONS variable is tucked in your environment settings, it is shown nowhere else. To remedy this,
Press the Windows key and the Pause/Break key simultaneously
A window should popup, click on "Advanced system settings"
Click on "Environment Variables"
Check System Variables.
Delete the _JAVA_OPTIONS entry.

This "error" will happen if the variables JAVA_TOOL_OPTIONS or _JAVA_OPTIONS are set. I don't believe it is or should be of much concern to anything. As long as the application runs fine I see no real issue. So no, it is not very important, and seeing as the application was still built (and is likely working normally), I don't see a reason to try and correct it.'
Additionally if you do have errors within the application where this is the root cause, this might be of some help.
Relevant/important post from the thread:
A quick Google search indicates that this is output from the Java
virtual machine upon realizing that certain environment variables,
JAVA_TOOL_OPTIONS and JAVA_OPTIONS have been set.
http://www.nbl.fi/~nbl97/java/tuning/troubles/
These variables might be introduced in your Eclipse launch
configuration. More likely, they may have been set in your
workstation's environment by something you've recently installed.
On Windows XP, you can access the environment variables by right
clicking on "My Computer", selecting "Properties", switch to the
"Advanced" tab and click "Environment Variables". In that window, you
should be able to see if the environment variable has been set up.
Alternatively, you can open a command prompt and type "SET" to see
what environment variables have been set.

Find_java.exe in Android SDK doesn't find Java

I've definitely got JDK 1.6.0 installed in C:\Program Files\Java\jdk1.6.0_35, but it never seems to be able to find it when I try to open the SDK Manager. In task manager, find_java.exe shows up until I stop it (will run for hours).
Are there some environment variables I have to set for this to work?

As you are using Windows system, use following way to set your JAVA_HOME and CLASSPATH Environment variables.
Windows XP
Select Start, select Control Panel. double click System, and select the Advanced tab.
Click Environment Variables. In the section System Variables, find the PATH environment variable and select it. Click Edit. If the PATH environment variable does not exist, click New.
In the Edit System Variable (or New System Variable) window, specify the value of the PATH environment variable. Click OK. Close all remaining windows by clicking OK.
Windows Vista:
From the desktop, right click the My Computer icon.
Choose Properties from the context menu.
Click the Advanced tab (Advanced system settings link in Vista).
Click Environment Variables. In the section System Variables, find the PATH environment variable and select it. Click Edit. If the PATH environment variable does not exist, click New.
In the Edit System Variable (or New System Variable) window, specify the value of the PATH environment variable. Click OK. Close all remaining windows by clicking OK.
Windows 7:
From the desktop, right click the Computer icon.
Choose Properties from the context menu.
Click the Advanced system settings link.
Click Environment Variables. In the section System Variables, find the PATH environment variable and select it. Click Edit. If the PATH environment variable does not exist, click New.
In the Edit System Variable (or New System Variable) window, specify the value of the PATH environment variable. Click OK. Close all remaining windows by clicking OK.
Now in Addition for the Linux Based System following steps used to set JAVA_HOME and CLASSPATH variables,
Open root folder
From the View Menu , ticK "Show Hidden Files" , or press Ctrl + H.
Now you can see a system hidden file called .bashrc
Right click and open it editor, and write following command at the end.
PATH=$PATH:/opt/jdk1.6.0_21/bin
export PATH
JAVA_HOME=/opt/jdk1.6.0_21
export JAVA_HOME
NDK_HOME=/opt/android-ndk-r8
export NDK_HOME
Save and Exit.

May be you are forgetting the PATH environmental variable. To check this use,
In Unix/Linux systems,
echo $PATH
echo $JAVA_HOME
In Windows systems,
echo %PATH%
echo %JAVA_HOME%
If both the tests showed you empty lines, then you may need to set them again.
To set them do this. First try reinstalling java with UAC turned off.
If it failed, do this at the cmd
SetX PATH %PATH%;<path_to_jdk/jre>\bin\
SetX JAVA_HOME <path_to_jdk/jre>
Hope it helps and thinking you are using windows.