NOTE: The question is not about the difference between JDK and JRE.
Oh, I am sorry. The question is not discuss about JDK and JRE. But I cannot express clearly in my title. So I try to explain in here.
I want to know the difference between two folders!
C:\Program Files\Java\jdk1.8.0_161\jre and C:\Program Files\Java\jre1.8.0_161
Describe in details:
I am new to JAVA. I have installed the JDK in my Windows 10. When I install jdk, there were two steps. After double click jdk-8u161-windows-x64.exe, two steps as follows:
Step 1: install jdk. (In C:\Program Files\Java\jdk1.8.0_161)
Step 2: install jre. (In C:\Program Files\Java\jre1.8.0_161)
But when I open the jdk1.8.0_161 folder. I can also find a jre folder.
Could anyone tell me the difference between C:\Program Files\Java\jdk1.8.0_161\jre and C:\Program Files\Java\jre1.8.0_161?
If they are the same, why is jre installed in the installation process of jdk ? Are they duplicated?
In other world, is Step 2 needless?
The JRE within the JDK C:\Program Files\Java\jdk1.8.0_161\jre (also referenced as private JRE) is used by the JDK tools. The JRE outside C:\Program Files\Java\jre1.8.0_161 (also referenced as the public JRE) should is meant to be used by the Java applications.
private JRE
contains the library (attach.dll) needed for the use of the attach API
will be uninstalled with the JDK
public JRE
registers the Java Plug-in and the java web start in the browsers
this JRE is registered in the system, e.g. as runtime for Java applications, the Java control panel
can be uninstalled separately from JDK
I am not able to start eclipse on Windows 7. It was working fine yesterday. Here is the screenshot of error when I start eclipse:
Java versions from CMD
Why it gives different versions for java and javac?
My java home is set to Jdk 7 as below:
JAVA_HOME = C:\Program Files\Java\jdk1.7.0_60
Note: I have jdk 8 installed on my machine but I have not set jdk 8 path.
This question has been asked couple of times but I am not able to resolve it on my machine so please do not mark it as duplicate.
In the environment variables check your path whether it is starts with C:\ProgramData\Oracle\Java\javapath
if yes then please remove it and try again
More than likely you've installed JDK 1.70_60 prior to installing JRE 1.8.0_51.
This would mean that your compiler javac is found within the JDK distribution (Java Development Kit) and your java runtime is found within the more recently downloaded JRE (Java Runtime Environment). JRE does not contain the javac (Java compiler).
I was recently facing the same issue, Java 8 installer prepends to the Windows PATH variable C:\ProgramData\Oracle\Java\javapath that is why you are seeing different versions for java and javac
Your eclipse might not be pointing to the right JDK.
Open your eclipse.ini configuration file for editing. This can be found in the same folder with eclipse.exe file.
replace:
-vm C:\ProgramData\Oracle\Java\javapath\javaw.exe
with:
-vm
C:/Program Files/Java/jdk1.7.0_60/bin/javaw.exe
Then, restart eclipse.
I have recently installed jdk 8. Java 8 installer prepends to the Windows PATH variable C:\ProgramData\Oracle\Java\javapath and this is the reason I was seeing different versions for java and javac
For those who runs on the same issues, I have found nice explanation here
I am building a project in Java.
I have this error:
Unable to locate tools.jar. Expected to find it in C:\Program Files\Java\jre6\lib\tools.jar
I have installed a JDK and the folder: C:\Program Files\Java\jre6\lib is in my system but the file tools.jar is not there.
Yes, you've downloaded and installed the Java Runtime Environment (JRE) instead of the Java Development Kit (JDK). The latter has the tools.jar, java.exe, javac.exe, etc.
In case this is still an issue for anyone, I have a bit of clarification on the previous answers. I was running into this same issue using ant with only a JDK installed. Although, the JDK installer gave me a directory structure like this:
Directory of C:\Program Files\Java
05/08/2012 09:43 AM <DIR> .
05/08/2012 09:43 AM <DIR> ..
05/08/2012 09:46 AM <DIR> jdk1.7.0_04
05/08/2012 09:19 AM <DIR> jre6
05/08/2012 09:44 AM <DIR> jre7
0 File(s) 0 bytes
and when I ran ant, it complained about not finding tools.jar under the jre7 subdirectory. It wasn't until I set "JAVA_HOME=C:\Program Files\Java\jdk1.7.0_04" that the error went away.
Install the Java SDK.
Add a System Environment Variable called JAVA_HOME with the value of JDK location.
Go to Control Panel\System and Security\System. Advanced System Settings, Environment Variables, System Variables, New... Example:
Variable Name:JAVA_HOME
Variable Value: C:\Program Files\Java\jdk1.7.0_21
Close/reopen your CMD window so that the new variable takes effect before attempting to re-run the ant command.
I had the same problem and copying C:\Program Files\Java\jdk1.6.0_26\lib\tools.jar to C:\Program Files\Java\jre6\lib\ext worked for me
If you have installed JDK 9.0.1 you will also have this problem as the tools.jar has been deprecated. See migration document.
Set your JAVA_HOME environmental variable to point to C:\Program Files\Java\jdk1.7.0_02.
If you are in Linux you can solve this by installing java on the system:
sudo apt-get install openjdk-7-jdk openjdk-7-jre
No, according to your directory structure, you have installed a JRE, not a JDK. There's a difference.
C:\Program Files\Java\jre6\lib
^^^^
It should be something like:
C:\Program Files\Java\jdk1.6.0_24
Don't spend too much time looking for tools.jar. If you get an error like that, don't be upset.
If you already have java JDK 1.5, go to your lib folder, and the tools.jar should be available there. Copy and paste it in your ant bin folder, then try to use the command ant -version.
You should see the expected result.
I had the same issue on a linux machine. I was quite frustrated at first, because I have installed both the JDK and JRE. I am using version 1.6, 1.7 and 1.8 simultaneously, and I have played a lot with the alternatives to have everything set properly.
The problem was quite stupid to solve, yet counter-intuitive. While I was using the correct JDK, I paid attention to the path of the tools jar maven complained about - it was expecting it to be
$JAVA_HOME\..\lib\tools.jar
The $JAVA_HOME variable pointed directly to my jdk folder (/usr/local/java which was also the correct $PATH entry and alternative sym link). It actually searches for the lib folder outside the java directory, because:
$JAVA_HOME\..\lib\tools.jar
will resolve to
/usr/local/lib/tools.jar
and that is not a valid location.
To solve this, the $JAVA_HOME variable should instead point to this location /usr/local/java/jre (assuming the JDK path is /usr/local/java) -- there is actually jre folder inside the JDK installation directory, that comes with each JDK. This new setup will cause maven to look at the JRE directory, that is part of the JDK:
$JAVA_HOME\..\lib\tools
which now resolves to
/usr/local/java/jre/../lib/tools.jar
and finally to
/usr/local/java/lib/tools.jar
which is where the tools.jar really resides.
So, even if you are indeed using the JDK instead of the JRE, the $JAVA_HOME has to point to the JRE. Remember, the OS alternative should still refer to the JDK.
go to your jdk path where you installed your java
For e.g In my PC JDK installed in the following path
"C:\Program Files\Java\jdk1.7.0_17\";
After go to the lib folder e.g "C:\Program Files\Java\jdk1.7.0_17\lib"
in the lib directory there is tool.jar file
Copy this file and past it in the lib forlder of jre7 directory
for e.g
"C:\Program Files\Java\jre7\lib"
You may face similar problem on Ubuntu:
Embedded error: tools.jar not found: /usr/lib/jvm/java-7-openjdk-amd64/jre/../lib/tools.jar
The problem is with JAVA_HOME that is not set properly.
So, on Ubuntu 14.04 x64 using Java8:
sudo apt-get install openjdk-8-jdk openjdk-8-jre
export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64
As many people mentioned, it looks like you are looking in your JRE instead of the JDK for the tools.jar file.
I would also like to mention that on recent versions of the JDK, there is no more tools.jar file. I downloaded the most recent JDK as of today (JDK version 12) and I could not find any tools.jar. I had to download JDK version 8 (1.8.0) here https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html to get the tools.jar file. I downloaded that version, took the tools.jar file and put it into my recent version's lib folder.
It's worth observing that tools.jar has been removed from the JDK since Java 9. https://docs.oracle.com/javase/9/migrate/toc.htm#JSMIG-GUID-055EA9F4-835E-463F-B9E1-9081B3D9E55D
If people are facing this issue compiling a Java program with JDK 9+, you may need to review the dependencies of your projects.
In my case, I was trying to compile a project using AspectJ and the Maven plugin org.codehaus.mojo:aspectj-maven-plugin:1.11. After searching online, I found an alternative that supports Java 9+: dev.aspectj:aspectj-maven-plugin:1.13.M3.
I had the same problem even after installing Java JDK and set JAVA_HOME to ..\jdk1.6.0_45\bin folder.
Ant is still trying to find tools.jar in C:\Program Files\Java\jre6\lib folder.
I've fixed it by adding JAVACMD environment variable and set path for it to java.exe in the jdk folder.
In my case it was C:\Program Files\Java\jdk1.6.0_45\bin\java.exe
it has been solved with me in windows os by setting the JAVA_HOME variable before running as follows:
set JAVA_HOME=C:\Program Files\Java\jdk1.8.0_111
Make sure that both the %JAVA_HOME% and %JAVA_HOME%/bin paths are added to your PATH variable.
All the answers about copying tools.jar into the correct position is a poor idea at best.
Make sure that your IDE can find these jars the way it was designed and intended for.
In eclipse window> preferences>Java> Installed JRE, I pointed the directory to the jre directory in the jdk 1.7 and i worked file for me
e.g C:\Program Files\Java\jdk1.7.0_71\jre
I had my JDK_path (C:\Program Files\Java\jdk1.7.0_79) in my JAVA_HOME and also the JDK_path\bin in my PATH. But, still my ant was using the JRE instead of JDK.
The issue was I had C:\ProgramData\Oracle\Java\javapathbefore my JDK_path in PATH variable. I simply moved my JDK_path before the oracle one and the issue solved.
solving this problem I have simply copied the tools.jar file from C:\Program Files\Java\jre1.8.0_112\lib to C:\Program Files\Java\jdk1.8.0_112\lib so that I have two tools.jar files instead of one and problem disappeared.
Expected to find it in C:\Program Files\Java\jre6\lib\tools.jar
if you have installed jdk then
..Java/jdkx.x.x
folder must exist there so in stall it and give full path like
C:\Program Files\Java\jdk1.6.0\lib\tools.jar
Make sure that your classpath is set correctly and pointing to the correct version of the JDK that you have installed. Also, are you using Open JDK? I have had this issue before after I tried to move from open JDK to Suns JDK. This is an example of how that issue could be fixed.
maven-compiler-plugin use jdk ,not jre,
tools.jar is in C:\Program Files\Java\jdk1.6.0\lib\tools.jar
you must config project JRE System Libary with jdk,not jar. This is the simplest solution.
Right click on your ant file
Go to "Run as" then click on "Ant Build..."
Go to the "JRE" tab
Select a JDK and not a JRE
For me what's working: I downloaded an old version of Java 1.7
I actually set my JAVA_HOME from C:/program files X86/Java BUT after I installed the 1.7 version I had another Java in program files/Java. And at this moment I found the tools.jar here. Then I changed for this new path and it's working
I was also facing the same error.
This was removed after setting Java_Home path to C:\Program Files\Java\jdk1.8.0_121.
Please ensure bin is not included in the path and no slash is there after jdk1.8.0_121 after you have defined %JAVA_HOME%\bin in the system path variable.
If you're in a RHEL environment the package name containing tools.jar would end with "openjdk-devel".
This is the solution for Windows: in Computer > Advanced system settings > Advanced > Environment variables..., add this in System variables:
I have downloaded tools.jar and after that I copied it into path in error message.
C:\Program Files\Java\jdk-11.0.1\bin > paste here tools.jar
After that I have restarted Spring Tool Suit 4 and everything was working.
When I was trying to fix that problem I have made new environmental variable:
Control Panel / System / Advenced / Environmental variables / new
Name : JAVA_HOME
Value: C:\Program Files\Java\jdk-11.0.1
But I do not know is it necessary.
maybe you have updated the JREs in the OS, and the addition has added in the "path" of the environment variables an entry ".../Oracle/jer" that overwrites your JAVA_HOME.
try to remove it from the "path" by leaving JAVA_HOME.
When I type "java -version" from command prompt, I get the following warning :
Error loading: C:\Program Files\Java\jre6\bin\msvcr71.dll
My JDK is in the following directory :
C:\Program Files (x86)\Java
And I have also given the path to bin as :
C:\Program Files (x86)\Java\jdk1.8.0\bin
Then, what is the problem?
Well, first off, you've installed a jdk or jre version 1.6 and then added the 1.8 (which I'm guessing is a ver early non final version). That's why your JDK 1.8 executable is looking for libraries in your JRE6 install. Try uninstalling all JDKs/JREs and reinstall only the one you want to use. And if that doesn't work, try installing one of the stable releases like 1.7 from here
http://www.oracle.com/technetwork/java/javase/downloads/index.html
Try using the x64 version. Based on your paths you are using x86 version of java jdk. Your path is looking for the msvcr71.dll on your x64 location.
Another thing to check, look into your environment variables and check if there are other instances of the java path there. You should have JAVA_HOME as a variable and include it into your path like so:
%JAVA_HOME%\bin