Develop Reference

Java -version prints a wrong version

I have multiple versions of Java installed in the environment(I know it is bad). I've set the JAVA_HOME to jdk 1_4 directory. This is not installed, but extracted from zip and placed it somewhere. We have java 1.8 JRE also installed in the system. I never set the path to this installed directory. Now i'm trying to run some ant script that depends on jdk 1_4. I get some exception saying that it is not able to find tools.jar in java1.8... .
My question is that when the path and java_home are set to jdk 14 why does the ant look for 1.8 version of java? I'm confused.
Update: I have looked up the duplicate issue.
Additional details: Java -version prints 1.8 with jdk 14 in the path and java_home. I uninstalled 1.8. reopened cmd tried java -version, now it errors out saying that it is not able to find java1.8 instead of trying to find the next java available in the path or java_home.
Error shown:
C:\Users\usrpao>java
Error: could not open `C:\Program Files\Java\jre8\lib\amd64\jvm.cfg'

I have multiple versions of Java installed in the environment(I know it is bad). I've set the JAVA_HOME to jdk 1_4 directory.
Not wrong at all. I have a similar setup because I have to switch between Java version.
First, install Java JDKs in the root of your drive. No spaces in the directory names. For example, C:\Java\Java-1.6-21 and C:\Java\Java-1.7-5.
In your Environment Variables section in your System Control Panel (under Advance), create an environment variable to point to each one of these Java Home directories. For example, JAVA_HOME_17 = C:\Java\Java-1.7.5 and JAVA_HOME_16 = C:\Java\Java-1.6-21. This should be a System Environment variable.
Create a JAVA_HOME environment variable that points to the Java version you want: JAVA_HOME = %JAVA_HOME_17%.
Now in the System PATH, prefix the PATH (the very first entry) with %JAVA_HOME%\bin.
When you open a console window, your default java and javac commands will be the correct Java version.
If you need to change a version, change the JAVA_HOME environment variable to point to the correct environment variable and open a new console window. Now that new Java will be in your path.
NOTE: It is vitally important that %JAVA_HOME%\bin is in the first part of your PATH before C:\Windows\System32. You don't want the java.exe that exists in that directory to be your default java.

You haven't specified the operating system, so:
on windows, java installs a java.exe in C:\Windows\system32, which is probably on the path before java_home, and so gets picked up
on Linux, various distributions that support multiple installed java versions will also have some symlink earlier on the path. Run 'which java' to determine where that symlink is

Multiple java versions in the system is the problem, I uninstalled all the java versions first. Restarted my machine. Path and java home points to the jdk 1.4. java -version now points to the version specified in the path. Thanks all.

Problems setting the JAVA_HOME variable

So I just downloaded Android Studio, and am trying to set the JAVA_HOME variable so I can run it. I'm using windows 8 and have followed all the instructions I've been able to find to no avail... went to advanced system settings > environment variables and then set the JAVA_HOME variable with the value containing my path to jre7. I've double checked the path a million times, I don't see anything wrong with it(C:\Program Files (x86)\Java\jre7). I know the variable name is right, and I know that windows is excepting the variable, I've even restarted twice. What am I doing wrong here? The only thing I can think of that may be wrong is the fact that I'm pointing to a jre instead of a jdk, but I've always thought that both worked... anyway, the exact error message I get when I try to open Android Studio says:
No JVM installation found. Please install a 64-bit JDK. If you already
have a JDK installed, define a JAVA_HOME variable in Computer > System
Properties > System Settings > Environment Variables.
If a jre doesn't work in place of a jdk, then how do I go about getting one? I know nothing about Java I just want to get into this IDE and play around with Android.

No JVM installation found. Please install a 64-bit JDK.
It's asking for a 64-bit JDK. You say your environment variable is pointing at the following directory:
C:\Program Files (x86)\Java\jre7
There's two things wrong here. First, you're pointing to a JRE - Java Runtime Environment. This is not a JDK - Java Development Kit. The JRE is for running Java applications; the JDK is for developing Java applications. There's a significant difference there.
Secondly, as others have mentioned, you're pointing the environment variable to the 32-bit version. You need a 64-bit JDK. This will be installed at C:\Program Files\Java\jdk1.7.0_XX or similar, by default.
You can acquire a JDK installation from Oracle.

Here is the official installation instructions - http://docs.oracle.com/javase/7/docs/webnotes/install/windows/jdk-installation-windows.html
The important thing is
Set JAVA_HOME to the location where jre or jdk is installed
Add %JAVA_HOME%/bin to your path variable.
Make sure you add these to "System Variables" and not in "User variables for xxx"

By default, c:\Program Files (x86) (environment variable ProgramFiles(x86))is used for 32-bit installations. 64-bit installations use c:\Program Files (environment variable ProgramFiles).
When I open a cmd box on my Windows 7 64-bit, I can issue the "set" command to get
ProgramFiles=C:\Program Files
ProgramFiles(x86)=C:\Program Files (x86)
ProgramW6432=C:\Program Files
This should be similar under Windows 8.

No JVM installation found. Please install a 64-bit JDK
This is looking for a 64bit version of the java JDK.
C:\Program Files (x86) is the x86 not 64bit.
Click the link below and make sure to download the x64 version.
Java SE Development Kit 7 Downloads
Then the folder path should be
C:\Program Files\Java\jre7

Try runing Android Studio as administrator after setting the JAVA_HOME variable!
It worked for me...

Same thing happened to me and it turns out that all I had to do was unblock the file. Go to the file properties and at the bottom where it tells you it's from another computer and is blocked, just unblock it. This may not be true for everyone but it probably is if the path code is exactly what it should be and still isn't working.

the solution is simple,
I think your java path contains /bin
C:\Program Files\Java\jdk1.8.0_181
just path to the folder of JDK
like C:\Program Files\Java\jdk1.8.0_181
don't forget to restart your IDE or Code Editor

Android SDK r20 - Windows 7 - Install Java JDK Not Found

Android SDK installation doesn't find JDK is not the same release as this, and the solution "back" then "next" doesn't work.
I have tried installing various versions of Java and nothing seems to be working. I've been trying to get this installed for the last 3 days. Solutions I have tried that do NOT work:
Pushing the back button then the next button.
Adding an Environment Variable for JAVA_HOME that points to the System32 path and the actual java install directory.
Installing various versions of Java. (Java 6 and Java 7)
The install file is called installer_r20.0.3-windows and is the current exe available at http://developer.android.com/sdk/index.html

Ok, looking at to your JAVA_HOME path which is C:\Program Files\Java\jdk1.6.0_34\bin I suggest you to change it as C:\Program Files\Java\jdk1.6.0_34\. There is no need to add bin folder's path in the JAVA_HOME Path.

On my Win7 Ultimate 64 bits/ i need multiple things
Set SystemEnvironment Variable JAVA_HOME = C:\Program Files\Java\jdk1.7.0_07
Add the same value to SystemEnvironment Variable PATH, but make sure to put it before system32 path
PATH = C:/Program Files/Java/jdk1.7.0_07;C:\Windows\system32; ....... (... = current value)
and most important , i guessed. Rename c:\windows\system32\java.exe -> c:\windows\system32\java.exe.old
Restart the installer (my case = installer_r20.0.3-windows.exe )
Voila!
This might help safe other's time

Setting JAVA_HOME environment variable in System variable to C:\Program Files\Java\jdk1.7.0_07\ did solve my problem.
A couple of points to note.
No need to specify bin or jre folder name.
You will need to cancel and restart the Android SDK installation. Previous/Next may not work.
I just copied the folder name from Windows explorer address bar. No need to replace the \ with /.

A JRE or JDK must be available in order to run Eclipse. No JVM was found after searching the following locations

Eclipse is unable to open, have used eclipse before and has open before without a problem. Now I keep getting the following error message:
A Java Runtime Environment (JRE) or Java Development Kit (JDK) must be available in order to run Eclipse. No Java virtual machine was found after searching the following locations:
Have gotten eclipse to open and work on projects before and won't open.
Here is a screen shot of what I keep getting:

You can explicitly tell Eclipse where to find it. Open eclipse.ini and add the following lines to the top of the file:
-vm
/absolute/path/to/jre6/bin
Update: I just nailed down the root cause on my own Windows machine. The GlassFish installer complained with exactly the same error message and after digging in GlassFish forums, the cause was clear: a corrupt JRE install on a Windows machine. My JRE came along with the JDK and the Java 6 JDK installer didn't install the JRE properly somehow. A DLL file was missing in JDK's JRE installation. After I reinstalled the standalone JRE from http://java.com, overwriting the old one, the GlassFish installer continued and also Eclipse was able to start flawlessly without those two lines in eclipse.ini.

I got this problem because i uninstalled the jdk version 13 and reinstall the jdk version 8
Even though i have updated the path variables eclipse still pick the old configuration.
You need to edit the eclipse.ini file which is in your folder where eclipse.exe is placed.
Just update this file with the latest path so eclipse can pick it up

It usually is because:
you indicated the wrong jvm path in your -vm argument: see this SO question for an concrete example.
the eclipse.ini got corrupted somehow (if it hasn't been modified, this isn't it, but if setting a jvm path doesn't work, ... I would replace the eclipse.ini by one coming from a fresh installation just to be sure)
the java which eclipse search by default is no longer accessible (because the $PATH is no longer up-to-date)
More details on the wiki page "Finding a VM, Using JNI Invocation or Executing Java"
No -vm specified
When no -vm is specified, the launcher looks for a virtual machine first in a jre directory in the root of eclipse and then on the search path.
If java is found in either location, then we look for a jvm shared library (jvm.dll on window, libjvm.so on *nix platforms) relative to that java executable.
If a jvm shared library is found we load it and use the JNI invocation api to start the vm.
If no jvm shared library is found, we exec the java launcher to start the vm in a new process.
As mentioned in "FAQ How do I run Eclipse?":
Eclipse DOES NOT consult the JAVA_HOME environment variable.
So I would check your $PATH, starting by n new shell sesion (whatever your OS is), typing 'java -version' to see if it still returns anything.

Copy javaw.exe from C:\Program Files\Java\jre1.8(or)1.6(or)1.7\bin
and paste it inside Eclipse folder
where eclipse.exe is there. That's all.

Here is how I fixed mine:
find the location where your jre is installed. in my case, it was located at C:\Program Files\Java\jdk1.7.0_10
copy the jre folder and paste it where your eclipse files are located (where eclipse.exe is located).
when you download eclipse, you get a .zip package containing eclipse.exe and all the other files needed to run eclipse but it is missing the jre files. so all you need to do is to find where jre folder is located on your hard drive and add it to the rest of the eclipse package.

I had the same problem and the issue was that I had a 32 bit version of Eclipse running on my 64 bit machine and it wanted the 32 bit version of JRE.
I changed Program Files to Program Files (x86) in the eclipse.ini file like so:
-VM
C:Program Files (x86)\Java\jre6\bin
and that solved the problem.
You may want to just install the 64 bit Eclipse, but this will take care of the error.

Did you install Java via the java.com web browser auto install? If so, then that's your problem! You need to to the "manual" install: http://www.java.com/en/download/manual.jsp
It's just a matter of having the correct match of 32-bit Eclipse/32-bit Java or 64-bit Eclipse/64-bit Java. Many 64-bit Windows have 32-bit browsers and the latter is the version of Java that the auto-installer will provide - not what the 64-bit Eclipse wants.

Make sure the install path of JDK is in your Path variable in Windows.

adding -vm C:/Program Files/Java/jdk1.6.0_29/bin/javaw.exe to the .ini file helped me.

Is so simple,only add your java path for example:
C:\Program Files\Java\jdk1.8.0_121\bin
in PATH system variable

I have faced the similar issue earlier with Eclipse and STS IDE'S
Please check weather JDK/JRE is available or not in your machine. If not please install JDK and setup the environment variables.
Even after step 1, if you are still facing the issue then it's time to set the vm argument in eclipse.ini or sts.ini in the following way.
-vm
C:Program Files (x86)\Java\jre8\bin

I also had same problem when developing android applications using eclipse IDE.
I solved it by removing all the java installations (I had java 6 and 7 both) and re-install only jdk 7.

I got this fixed by doing the below steps,
1)
The eclipse finds the JAVA executables from 'C:\ProgramData\Oracle\Java\javapath'
The folder structure will contain shortcuts to the below executables,
i. java.exe
ii. javaw.exe
iii. javaws.exe
For me the executable paths were pointing to my (ProgramFiles(x84)) folder location
I corrected it to Program Files path(64 bit) and the issue got resolved
Please find the screenshot for the same.

Just to add on top of other answers:
Windows Users: You can give the PATH to JRE in eclipse.ini separated by '/' or '\'. It doesn't matter. Eclipse will pick it anyway. For example, in my windows system, either of the paths is fine (after -vm of course):
C:/Program Files/Java/jre1.8.0_181/bin
or C:\Program Files\Java\jre1.8.0_181\bin

Change the vm value in eclipse.ini file with the correct path to your JDK something like this,
-vm /Library/Java/JavaVirtualMachines/jdk-11.0.5.jdk/Contents/Home/bin
Path to eclipse.ini looks to me something like this,
/Users/tomcat/eclipse/jee-2018-09/Eclipse.app/Contents/Eclipse

This sometimes happen if you remove Java from your path variables.
To set the PATH variable again, add the full path of the jdk\bin directory to the PATH variable. Typically, the full path is:
C:\Program Files\Java\jdk-11\bin
To set the PATH variable on Microsoft Windows:
Select Control Panel and then System.
Click Advanced and then Environment Variables.
Add the location of the bin folder of the JDK installation to the
PATH variable in system variables.

I had this problem too on a win7 machine.
I wanted to update the jre with a jdk. So i deleted the jre folder and downloaded and unzipped the new jdk.
The issue was i manually deleted the jre folder, when instead i should've uninstalled it. This leaves a bunch of registry entries that still point to the old jre. Somehow eclipse still wants to use the old jre.
I couldn't uninstall the old java vm, i kept getting this error:
Error 1723. There is a problem with this Windows Installer package. A DLL required for this install to complete could not be run. Contact your support personnel or package vendor
So i had to use this MS utility to fix the uninstall:
http://support.microsoft.com/kb/2438651/
Then i had to install again the vm. I installed to the same location the original one was at, to avoid losing another hour! After that eclipse started correctly.
Julio

I just had this problem and fixed it this way. I noticed the error message has jre in it not jre6 or jre7, so i copied jre6 from program files to eclipse folder then renamed it from jre6 to jre, then it worked :p

Newb move on my part, but I had installed just the JRE instead of JDK. Installed JDK and my problem went immediately away.

I had this problem and it was due to my windows machine playing up. I went into control panel -> system -> advanced - environment variables.
I edited the PATH variable (which was already correctly set up), changed NOTHING, clicked OK to come back out of the screens.
Then eclipse worked. No idea why, except because windows. Hopefully this may help someone.

I had this issue; I fixed it by going to
Computer-->Properties-->Advanced Settings-->Environmental Variables
In the System Variables find the variable named PATH.
-->Select Edit
-->At the very end of the Path Variable, put a ";" then add your path of your JDK and put \bin\ at the end
Should be fixed.
Example:
System Variable-
C:\Program Files (x86)\Common Files.......HP\LeanFT\bin
JDK path-
C:\Programs Files\Java\jre1.8.0_121
Final Path -
C:\Program Files (x86)\Common Files.......HP\LeanFT\bin;C:\Programs Files\Java\jre1.8.0_121\bin\
Sources:
https://www.java.com/en/download/help/path.xml

Its simple.
JDK bin directory or JRE bin directory should be in path variable
Example :
Java Installed directory:
Assume your java installed in 'C:\Program Files\java\Jdk1.8.0_144' directory
Now you can find bin directory in 'C:\Program Files\java\Jdk1.8.0_144\bin'
Navigate to user's environment variable
Control Panel --> User Accounts --> User Accounts --> Change my environment variables
In popup click Path under User variables for section
Click Edit... button and another popup will appear
Click New button and enter C:\Program Files\java\Jdk1.8.0_144\bin
Click OK button and again OK button in Environment variables popup.
Now you can open your eclipse without error

I found a solution wherein the Eclipse.ini the location was the old version of Java, and after updating the new version of java the location of
-vm
C:\Program Files\Java\jre1.8.0_201\bin
was same so I had to change the directory to my new version of Java.
So solution is to just open the most updated Java version and copying its directory path and replacing it in the Eclipse.ini file.

Moderately future proof example for Linux-like systems. Assuming javac installed and on your path.
./eclipse -vm dirname $(readlink -f $(which javac))
This will find the directory where javac is installed, and pass as vm argument to eclipse.

If on Linux (ex: Ubuntu 18), try installing (or reinstalling in your case?) default-jre, as follows:
sudo apt update
sudo apt install default-jre
I had the same error when just trying to run the Eclipse installer (./eclipse-inst) on a fresh Eclipse download just now, and the installer wouldn't even run! Installing default-jre solved it!
Source:
https://linux4one.com/how-to-install-eclipse-ide-on-ubuntu-18-04/

In my case I had edited the eclipse.ini for a different purpose to include -vm parameter. That was causing the failure. I removed the -vm and following line where I had included \bin and that fixed the problem.

I got ERROR:
RESOLUTION :
in file eclipse.ini at below location :
make change as :
-vm
C:/Program Files/Java/jdk1.8.0_251/jre/bin/server/jvm.dll
Restart eclipse and error will be resolved

C:\Program Files\Java\jre1.8.0_221\bin
worked for me

What is JAVA_HOME? How does the JVM find the javac path stored in JAVA_HOME?

I would like to know what JAVA_HOME is. Where do I set the path of javac.exe and java.exe. It is in environment variables? When I compile a Java program from command prompt, how does the JVM find javac.exe?

JVM does not find java.exe. It doesn't even call it. java.exe is called by the operating system (Windows in this case).
JAVA_HOME is just a convention, usually used by Tomcat, other Java EE app servers and build tools such as Gradle to find where Java lives.
The important thing from your point of view is that the Java /bin directory be on your PATH so Windows can find the .exe tools that ship with the JDK: javac.exe, java.exe, jar.exe, etc.

JAVA_HOME and JRE_HOME are not used by Java itself. Some third-party programs (for example Apache Tomcat) expect one of these environment variables to be set to the installation directory of the JDK or JRE. If you are not using software that requires them, you do not need to set JAVA_HOME and JRE_HOME.
PATH is an environment variable used by the operating system (Windows, Mac OS X, Linux) where it will look for native executable programs to run. You should add the bin subdirectory of your JDK installation directory to the PATH, so that you can use the javac and java commands and other JDK tools in a command prompt window. Courtesy: coderanch

set environment variable
JAVA_HOME=C:\Program Files\Java\jdk1.6.0_24
classpath=C:\Program Files\Java\jdk1.6.0_24\lib\tools.jar
path=C:\Program Files\Java\jdk1.6.0_24\bin

The command prompt wouldn't use JAVA_HOME to find javac.exe, it would use PATH.

JAVA_HOME is a environment variable (in Unix terminologies), or a PATH variable (in Windows terminology). A lot of well behaving Java applications (which need the JDK/JRE) to run, looks up the JAVA_HOME variable for the location where the Java compiler/interpreter may be found.

JAVA HOME is used for setting up the environment variable for JAVA. It means that you are providing a path for compiling a JAVA program and also running the same. So, if you do not set the JAVA HOME( PATH ) and try to run a java or any dependent program in the command prompt.
You will deal with an error as
javac : not recognized as internal or external command.
Now to set this, Just open your Java jdk then open bin folder then copy the PATH of that bin folder.
Now, go to My computer right click on it----> select properties-----> select Advanced system settings----->Click on Environment Variables------>select New----->give a name in the text box Variable Name and then paste the path in Value.
That's All!!

JAVA_HOME is an environment variable which is read by some development tools like Apache Tomcat, Apache Maven, Gradle, Jenkins etc. Usually, JAVA_HOME is set to point to JDK instead of JRE because these development tools need to use tools like compiler, debugger, document generator etc. which are only available in JDK since JDK is a development kit. JRE is only meant for running java applications. JDK = JRE + Development tools
Consumer facing Java applications don't read JAVA_HOME variable and they just need to know where the JVM is located and that's why JVM location (directory) needs to be added to the PATH variable. This is automatically done for you when you install Java software. Whenever you try to run a Java application by either double clicking on the app or through command line, your operating system reads PATH variable to locate and run JVM and it doesn't look for JAVA_HOME variable.

use this command /usr/libexec/java_home to check the JAVA_HOME

JAVA_HOME is an Environment Variable set to the location of the Java directory on your computer.
PATH is an internal DOS command that finds the /bin directory of the version of Java that you are using. Usually they are the same, except that the PATH entry ends with /bin

Basically JAVA_HOME is use to set path of the java . it is use in windows. it's used for set path of the multiple software like as java EE , ANT and Maven.
this is the steps to solve your problem:
only for core java to set path :
path :"C:\Program Files\Java\jre1.8.0_77\bin"
but when you are use multi built like as ANT , core java then you are used JAVE_HOME in environment .
follow the steps :
JAVA_HOME:"C:\Program Files\Java\jre1.8.0_77\bin"
ANT_HOME:"C:\ant\apache-ant-1.9.6"
Path: JAVA_HOME, ANT_HOME;
it is the systematic way to set the environment variable..