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.
Related
I previously had Java 7 installed on my Windows PC. System environment variable also had location to it. I installed Java 10 without uninstalling 7 or changing the environment variable. Now when I go to CMD or Cygwin and enter Java -version it says Java 10.
I would think since I didn't change the environment variable that it would still be 7. How is Windows deciding what JDK to use?
Thanks!
Probably your JAVA_HOME or just PATH environment variables were changed.
Go to command line and do the following to check it:
> echo %JAVA_HOME%
For example, for me it gives back:
C:\Program Files\Java\jdk-9.0.4
How is Windows deciding what JDK to use?
Windows is NOT making decisions on its own. If you get version 10 information when you run java -version, it is because Windows is finding the folder containing java.exe corresponding to the version 10 first in the paths pointed to by the PATH environment variable. If you have installed Java using an installer, the installer would update the PATH variable for you. Check your PATH variable and you will see the Java 10 folder appearing there first and then Java 7 folder.
If you are using a java ide , you might find the location in JRE configurations. for example in eclipse :
windows > preferences > Installed JREs
.
Your JAVA_HOME variable might still be set to JDK 7 directory, however the Java 10 installation may have inserted it's /bin directory to the PATH.
Check to ensure that java 10 isn't on the PATH before java 7, or hasn't overwritten it.
CMD etc. check the path for the binaries for commands like java-version.
I am trying to run a compiled java class and getting errors but when I checked my java environments it points to different version.
Javac –version gives me 1.8.0
And
Java –version gives me 1.6.2
The Java_home and path is pointing to the 1.8 version.
Please help.
Java installation under Windows is sometimes a really severe source of pain. The following assumes that you have Windows:
Check your path variable
Check JAVA_HOME variable
Newer versions of Java (1.6 ?, but 1.7 and 1.8) copy some Java executables into the System32 directory of the windows installation. Simply delete this files (or move them somewhere else for easy recovery)
running java applications by using .bat files a specific JDK / JRE can be provided.
There may be more sources of your problem. For example with Maven you depend on JAVA_HOME, with Eclipse you have the project settings, ...
Please check the following :
1) Check your path variable
2) Check JAVA_HOME variable
3)Delete the java,javaw and javaws .exe file from the system32 folder
java.exe while java installation gets copied under System32 directory. Also we tend to append java path in the end of the path variable. This causes running java command pointing to the one in System32 (it takes the first path value that is encountered and ignores rest, in this case java of system32 folder). And when it cannot find javac it looks to other values of path and finds it towards the end for the java JDK (this is the one you want to use).To overcome this problem give path to your JDK for example C:\ProgramData\Oracle\Java\bin as the first entry in the windows path variables. Even before your system32 entry. This ensures you point to only one java. My path entry looks something like this:-
%JAVA_HOME%\bin;%SystemRoot%\system32;
If you are running Windows, you could perhaps check the path environment variable. It might point to an older JRE installation.
One possibility is that your Java link is inconsistent. Go to this location (Windows):
C:\ProgramData\Oracle\Java\javapath and check where to does java.exe point.
In case it is not up-to-date consider fixing it with:
mklink /d C:\ProgramData\Oracle\Java\javapath "C:\Program Files\Java\<your JDK>\bin\"
(you may need to remove javapath old link before you create a new one)
When i am running Jenkins which checks out code from a repository and perform mvn package or some command. I get this error:
Unable to locate the Javac Compiler in: /usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0.x86_64/jre/../lib/tools.jar
Please ensure you are using JDK 1.4 or above and not a JRE (the com.sun.tools.javac.Main class is required).
In most cases you can change the location of your Java installation by setting the JAVA_HOME environment variable.
My JAVA_HOME points at jdk location only.Still it looks at
/usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0.x86_64/jre/../lib/tools.jar
for the compiler.Why is that???
It seems the problem is with the code ..It points to /usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0.x86_64/jre/../lib/ for the tools.jar,whereas it needs to look into the /usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0.x86_64/lib/ where the jar is present.I tried copying the jar to jre /lib/ but to no avail.Any solutions for this...
Thanks for d answers anyway..
You need jdk (java development kit) to compile java programs. jre only use to run compiled java programs. in your case its point to a jre and thats why you are getting this.
you can download the jdk and install.
you can download jdk rpm from here
http://www.oracle.com/technetwork/java/javase/downloads/jdk7u9-downloads-1859576.html
use this to choose java alternative if you have already installed.
/usr/sbin/alternatives --config java
Uninstall the installed JRE. Keep only one JAVA defined by JAVA_HOME and define your lib and classpath with respect to JAVA_HOME.
I'm using a Windows .bat script and I set JAVA_HOME as C:/Program Files/Java/jdk1.6.0_32
when I do a java -version, it still shows the 1.3
How can I fix this? What am I doing wrong?
For me the issue was in my PATH variable, C:\ProgramData\Oracle\Java\javapath; was added by java windows install before my %JAVA_HOME%\bin;.
So I'd echo %JAVA_HOME% pointing to a JDK7 and java -version showing jdk8.
I'd to put %JAVA_HOME%\bin; before C:\ProgramData\Oracle\Java\javapath; so that java -version displays jdk7.
Try %JAVA_HOME%\bin\java -version
If you modify JAVA_HOME, it's usually better to invoke java with an absolute path (using JAVA_HOME) because the new binary is probably not in the path (and then Windows will load the wrong binary).
Make sure that the PATH environment variable is pointing to %JAVA_HOME%\bin.
Be sure not to mix the system variable path and the user variable system path. I feel OK in calling java without the absolute path (when I know how JAVA_HOME and PATH are configured).
Calling java -version from command line, causes cmd.exe to do the lookup on the "known" directories. "Known" means PATH environment variable. It seems that your PATH contains a java 1.3 bin folder, and not 1.6.
JAVA_HOME is another variable, that is used (for example, and not only) by java wrappers, or by scripts executing some java stuff.
Try doing this:
SET JAVA_HOME=C:/Program Files/Java/jdk1.6.0_32
%JAVA_HOME%/bin/java -version
Add quotes where needed.
I had similar issue,in my case , I had two versions java installed. it can be fixed by uninstalling one version of java completely from system.
Had a similar scenario today - two Windows 10 devices - both have JRE 1.6 & 1.7.
When typing
Java -version
One device shows 1.6 the other 1.7.
This was preventing me running a third party JAR to install some software on the device showing 1.6 (which worked fine on the device showing 1.7 when running java -version), using:
java -jar ThirdParty.jar
As the JAR needed to be run by 1.7.
Cause of this was in the PATH environment variable - one device had the location of 1.6 first in the PATH list, moving the 1.7 location above the 1.6 location resulted in consistency using Java -version and allowed me to install the software.
java -version will consult the paths in the special environment variable Path. You need to select the java version you want and move it upwards the latter (click "Move Up"). You probably have that reference to JDK 1.3 in Path above your addition of JDK 1.6. Since that's the first thing the OS finds, that's what it chooses to run.
Executing the command again with the same window opened after changing the environment variables will not work. Re-open it
I know this question is old but this was my case and I wanted to re-explain further, similar to #DanBot 's case
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..