I cannot run my Ant build.xml since I updated to java 1.7.0_52 (or there about). I have been running it for years through Eclipse locally on my Windows 7 laptop - but with this latest jave jdk update somethings different (?).
BUILD FAILED
C:\workspace\WaterAspectsModel3\build.xml:329: Unable to find a javac compiler;
com.sun.tools.javac.Main is not on the classpath.
Perhaps JAVA_HOME does not point to the JDK.
It is currently set to "D:\Morten\Java\jdk1.7.0_52"
This is my jdk! So JAVA_HOME is pointing to a jdk (as is also clear from the error message). I have my JAVA_HOME with bin folder in my path as always. I've configured Eclipse - external tools configuration - with a JRE pointing to the same D:\Morten\Java\jdk1.7.0_52 (through "Separate JRE" setting). And I've tried a number of other configurations - all without luck.
I've been reading the tonnes of answers on lists here and other places and think I've tried all suggestions. Most seem to be cases where JAVA_HOME actually points to a jre and just needs to be corrected to jdk or there's a ";" in the path or something like that. None of these seem to apply in my case.
Any suggestions?
I was having the same message when running ANT through Eclipse.
What worked for me:
In Eclipse, access the menu: "Window -> Preferences";
Access "Ant -> Runtime", at the tree;
Access the Classpath tab;
Expand the "Global Entries" item;
Inside Global Entries, the path to tools.jar was wrong. It was pointing to an older version of Java;
I removed the wrong entry and added the correct one with "Add External Jars" button. It worked.
The solution
"Had to copy C:\Program Files\Java\jdk1.6.0_10\lib\tools.jar to C:\Program Files\Java\jre6\lib\ext" from here was great helpful and worked for me.
The real message is that Ant can't find com.sun.tools.javac.Main.
Which, together with the fact that the latest "Sun" (Oracle) JDK is 1.7.0_13 (or maybe _14, but definitely not the "_52" that your install dir indicates), makes me think that you're not using a distribution that Ant recognizes. You can verify this by running jar tvf $JAVA_HOME/lib/tools.jar, and looking for that class.
The Ant Manual talks about ways to work with different compilers. Since I've only used "Sun" compilers, I'm afraid that I can't give you any pointers.
Edit: you could also try setting fork="yes" in your build file. This should run the compiler executable rather than trying to invoke the compiler class.
Try adding JAVA_HOME\bin to your env PATH .
Add JAVA_HOME to Eclipse-Preferences-Java-Build Path-Classpath Variables.
Sorry for the unearthing,
I had the same problem, my solution doesn't need any modification in environment variables, and works for a recent JDK where the tools.jar can't be found.
Just go in the small down-arrow next to the ant run button
Then click "Configure external tools"
Then in JRE tab
Select a JDK installed on your computer, not a JRE, no problems if the selected JDK is not the same JDK/JRE as in your project.
It should be work now.
Related
I installed both correctly, but it doesn't matter if I set up the path to compiler correctly or not because it can't find gcc and g++. I checked it with explorer, they were at the correct location. I tried everything I could, even I ran Eclipse in backwards compatibility mode and as an administrator.
EDIT: I'll using Visual Studio 2012 for a while if Eclipse can't be at least as user friendly to having find a solution to the problem under one hour via web.
Download this , chose the desired compilers (gcc and g++) . Make sure you have the value C:\mingw64 in PATH variable under environment variables .
I had to reload my workspace in order to get Eclipse to recognize that.
Also, I had updated the Path variable.
Please follow the same in your case.
I couldn't make the Eclipse (LUNA) to find MinGW on my computer (there were no MinGW available in Preferences>C/C++/New C/C++ Project Wizard) even after I have specified PATH as "C:\MinGW\bin" in Preferences>C/C++/Build>Environment, so what I did afterwards was:
Create a simple "Hello world" C project without specifying any toolchains
(at this step I tried to Build All, and it failed)
Go to Project>Properties, suprisingly, here I could see MinGW GCC as an available choice for Current toolchain. Select it.
Now I could build and run the project
Hopefully, it helps!
Okay, so i wiped my PC clean today. Upon attempting to install Eclipse and the JDK i hit a snag.
I install the "ADT Bundle" from android developers.
I install the JDK to the default path
When i try to open Eclipse, it cannot find my JRE (which from what i understand comes in the JDK which i downloaded from the oracle website). I know it is properly installed because i can navigate to the install path and run java programs using the exe.
iv heard something about modifying environment variables to get it to find it but nothing has worked... i dont have a "PATH" variable listed.... i do have a "Path"... but changing either one does nothing to fix the problem... I have done this installation many times and it SHOULD be working...
any help on the subject would be greatly appreciated.
Since you wiped it clean, have you tried downloading Java Runtime Environment again (maybe you wiped it too)
The solution to this problem is such:
The "Path" enviroment variable needs to be under -user variables- NOT system variables
make a new user variable named "Path" and set the value to the absolute path of the java compiler
for me it was something like C:\Program File\Java\JDK1.7\bin
that should fix the problem of eclipse not finding the JDK/JRE...
if it complains about "JNI" then you need to make sure you are running the JDK and eclipse as the same achitechture (64bit java wont work with 32bit eclipse)
The "Path" environment variable needs to be defined or updated. If you are working in Windows 8 then you can navigate by following these steps:
Open > File Explorer
Right Click "Computer"
Select "Properties"
On the left hand side select "advanced system settings"
Under the "Advanced" tab, select "Environment Variables"
Locate the Path directory in the list under System
Edit the directory by entering a semi-colon after the last entry and then manually typing the location of your Java directory.
After the full address is entered, (Should look similar to --> C:\Program File\Java\JDK1.7\bin) click "Ok" on the screen to save your changes.
Something to keep in mind while updating your path. Make sure that you direct the path to the compatible version. If you downloaded the 64 bit eclipse, choose the 64 bit Java. If you do not remember the Eclipse version you downloaded, check your download file name against the files offered on Eclipse's website. If you follow these steps Eclipse should open up without a problem.
I have one JRE in C:\Program Files (x86)\Java\jre6 and that was the only one at the time I installed Eclipse. I have subsequently installed a complete JDK in C:\home\SFTWR\jdk1.6.0_21 and changed my JAVA_HOME environment variable to that. However, every time I start a new Eclipse workspace, it only picks up the old JRE and I have to manually remove it and add the new one.
How do I bind my Eclipse install to the new JDK so that every new workspace points to that only? I checked eclipse.ini but there was no reference there to which JRE to go to.
UPDATE:
I went into Prefs->Java->Installed JREs, added the new location, marked it as default, removed the other, and it was effective only for the current workspace. However, when I opened a new workspace, only the old JRE was available. So this didn't change the core Eclipse config that is applicable across all (at least new) workspaces
Finally got it: The way Eclipse picks up the JRE is using the system's PATH.
I did not have C:\home\SFTWR\jdk1.6.0_21\bin in the path at all before and I did have C:\Program Files (x86)\Java\jre6\bin. I had both JRE_HOME and JAVA_HOME set to C:\home\SFTWR\jdk1.6.0_21 but neither of those two mattered. I guess Eclipse did (something to the effect of) where java (or which on UNIX/Linux) to see where Java is in the path and took the JRE to which that java.exe belonged. In my case, despite all the configuration tweaks I had done (including eclipse.ini -vm option as suggested above), it remained stuck to what was in the path.
I removed the old JRE bin from the path, put the new one in, and it works for all workspaces.
The Installed JREs is used for what JREs to execute for your downstream Java projects and servers. As far as what JVM or JRE that is used to execute Eclipse process (workbench) itself that is controlled by your environment, history and eclipse.exe binary. So eclipse.exe itself decides what JRE Eclipse will execute itself with, not installed JREs preferences since those are not read until OSGi framework is up and running which is loaded after the JVM/JRE is picked.
So for new workspaces, Eclipse is going to use its currently executing JRE to populate the JRE prefs.
The best way I know how is to force eclipse.exe to use the JRE that you tell it via the -vm switch. So in your eclipse.ini do this:
-startup
plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.win32.win32.x86_64_1.1.100.v20110502
-vm
/path/to/exactly/what/jre/you/want/as/default/javaw.exe
...
Open the Java > Installed JREs preference page. Check the box on the
line for the JRE that you want to assign as the default JRE in your
workbench. If the JRE you want to assign as the default does not
appear in the list, you must add it. Click OK.
Source-http://help.eclipse.org/juno/index.jsp?topic=%2Forg.eclipse.jdt.doc.user%2Ftasks%2Ftask-assign_default_jre.htm
In eclipse go to
Window-> Java -> Installed JREs
You can remove your current installed jre and add the jdk by specifying the path to where the jdk is installed.
I ran into a similar issue where eclipse was not using my current %JAVA_HOME% that was on the path and was instead using an older version. The documentation points out that if no -vm is specified in the ini file, eclipse will search for a shared library jvm.dll This appears in the registry under the key HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\JavaSoft\Java Runtime Environment that gets installed when using the windows java installer (key might be a bit different based on 64-bit vs 32-bit, but search for jvm.dll). Because it was finding this shared library on my path before the %JAVA_HOME%/bin, it was using the old version.
Like others have stated, the easiest way to deal with this is to specify the specific vm you want to use in the eclipse.ini file. I'm writing this because I couldn't figure out how it was still using the old version when it wasn't specified anywhere on the path or eclipse.ini file.
See link to doc below:
http://help.eclipse.org/kepler/topic/org.eclipse.platform.doc.isv/reference/misc/launcher.html?cp=2_1_3_1
Finding a VM and using the JNI Invocation API
The Eclipse launcher is capable of loading the Java VM in the eclipse process using the Java Native Interface Invocation API. The launcher is still capable of starting the Java VM in a separate process the same as previous version of Eclipse did. Which method is used depends on how the VM was found.
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 the launcher looks for a jvm shared library (jvm.dll on Windows, libjvm.so on *nix platforms) relative to that java executable.
If a jvm shared library is found the launcher loads it and uses the JNI invocation API to start the vm.
If no jvm shared library is found, the launcher executes the java launcher to start the vm in a new process.
-vm specified on the command line or in eclipse.ini
Eclipse can be started with "-vm " to indicate a virtual machine to use. There are several possibilities for the value of :
directory: is a directory. We look in that directory for:
(1) a java launcher or
(2) the jvm shared library.
If we find the jvm shared library, we use JNI invocation. If we find a launcher, we attempt to find a jvm library in known locations relative to the launcher. If we find one, we use JNI invocation. If no jvm library is found, we exec java in a new process.
java.exe/javaw.exe: is a path to a java launcher. We exec that java launcher to start the vm in a new process.
jvm dll or so: is a path to a jvm shared library. We attempt to load that library and use the JNI Invocation API to start the vm in the current process.
My answer will overlap with amphibient's while adding on to it.
Your JAVA_HOME variable is fine, but you also need to append the following to your Path variable :
;%JAVA_HOME%\bin
This will allow your applications in your Windows environment to access your JDK. You should also restart your computer once you've added these environment variables before checking out if they work. In my case, even logging out and then back in didn't work : I had to completely restart.
If you want to check if the environment variables are set correctly, you can open up a command prompt and type >echo %JAVA_HOME and >echo %Path% to see if those variables are working correctly. While snooping around for solutions, I have also run into people claiming that they need to add quotations marks (") around the environment variables to make them work correctly ("%JAVA_HOME%"\bin) if your JAVA_HOME path includes spaces. I thought that this was my case at first, but after doing a full restart my variables seemed to work correctly without quotation marks despite the spaces.
when you select run configuration, there is a JRE tap up next the main tap, select "Workspace default JRE(JDK1.7)".
Be sure to use the jdk in Prefs->Java->Installed JREs ->Execution Environment
I have faced with the same issue. The resolve:
- Window-->Preferences-->Java-->Installed JREs-->Add...
- Right click on your project-->Build Path-->Configure Build Path-->Add library-->JRE system library-->next-->WorkSpace Default JRE
try to change the order:
right click on you project-> BuildPath->Configure...->Order and Export tab -> move jre7 UP.
I navigated to:
Eclipse>Pref>Java>Installed JRE>Search...
2 of them popped up and I checked the latest one. Before I did this I also went to About>Check for Updates and updated it. I didn't have to reinstall any JRE or JDK either. I might have done it a while back, except it was with 1.6 not 1.4. Hope that helps!
On windows I've tried different approaches
- setting JAVA_HOME, JRE_HOME and extending the PATH to point to the desiered jre18 but nothing helped
- disabling the JRE17 in the java control panel didn't helped either
What helped me out was to force eclipse to use the appropriate JRE in the eclipse.ini file e.g.
-vm
C:\java\jdk1.8.0_111\jre\bin\javaw.exe
#Stefan Michev answer also worked for me,
edit eclispe.ini to point to your installed JRE
-vm
C:\Program Files\Java\jdk-18.0.1.1-openj\bin
but to elaborate;
My application server uses JAVA_HOME and thus PATH so I needed Eclipse to pick up another JRE to run (so to be compatible with an installed plugin).
This Eclipse JRE is different than
than setting Window-> Preferences -> Java -> Installed JREs which as you see in the below image, is for building Java projects, so you can have different projects with different JDKs
Eclipse Installed JREs
could not open C:\Program Files\Java\jre6\lib\i386\jvm.cfg
is the error coming when i am trying to start eclipse ide.
my C:\Program Files has
jdk1.6.0_14
jdk1.6.0_17
jre6
folders.
path is set to
PATH: C:\Program Files\Java\jdk1.6.0_17\bin
what is the problem
i have seen this link but it is not solving my problem
can't find JRE in the JDK
I had similar problem on a Windows machine. I had moved my Java directory from inside "Program Files" (the space in the directory name was giving me trouble) over to c:\
I set all my PATH variables to the new location, restarted the machine and thought that would be enough. Nope
java -- version
Error: could not open `C:\Program Files\Java\jre1.8.0_66\lib\i386\jvm.cfg
This solution came from the good folks over at coderanch
Start regedit (just type "regedit" into the Run program) and work your way down to HKEY_LOCAL_MACHINE > SOFTWARE > JavaSoft
There you will find several different java directories
Java Development Kit
Java Plug-in
Java Runtime Environment
Java Update
Java Web Start
In each directory you'll find different directories for the different version of java (esp. Java Web Start). Open each and every one and you'll see that your old path is still listed. Double click the Name (left column) of the listing and manually type in the new path.
Open a new terminal and type in Java - version and you should be fine.
This problem can show up if you initially install Java in the default location (C:\Program Files) and then later re-install into another location.
The default installation copies java.exe, javaw.exe and javaws.exe to C:\Windows\System32. If you are in this situation and delete these files it will likely solve your issue.
(Thanks to Jay: http://jaykhimani.blogspot.com/2012/09/error-could-not-open-cprogram.html)
Problem: Eclipse Neon error: "C:\Program Files\Java\jre1.8.0xx.xx\jvm.cfg"
Solution Win7 Pro: System Properties > Enviorment Variables > System Variables > Path > Edit > #make sure the current JAVA directory appears first in the path if more than 1 JAVA directory exist.
In the path that follows, I moved "C:\ProgramData\Oracle\Java\javapath" behind the current directory "C:\Program Files\Java\jdk\bin;C:\Program Files\Java\jre\bin" > save
Path
C:\Program Files\Java\jdk\bin;C:\Program Files\Java\jre\bin;C:\apache-maven-3.5.0\bin;C:\ProgramData\Oracle\Java\javapath
I also had this problem and was having trouble finding a solution, but now I did!
If you uninstall your current running jre version and then install higher one you are good to go.
I was using jre1.6 when I had this problem but after installing 1.7 it was solved!
I recently got the same problem on my Windows 7. The issue was that two different paths were specified for Java in the path environment variable. This can be checked as follows.
On the command prompt, run the following command:
> where java
C:\Program Files (x86)\Common Files\Oracle\Java\javapath\java.exe <br/>
C:\Program Files\Java\jdk1.8.0_192\bin\java.exe
The first one was the cause of the issue and removed it from the path.
Eclipse is working now without re-installation.
Note: The environment vars have been as follows always:
JAVA_HOME=C:\Program Files\Java\jdk1.8.0_192
JRE_HOME=C:\ProgramFiles\Java\jdk1.8.0_192\jre
The problem is that your eclipse cant find jre.Just copy and paste your jre folder into eclipse folder and then start eclipse.Delete environment variable.
What worked for me was to go back to the Java webpage and download the Java jre instead of the jdk, since that is what the stupid computer is now looking for. Then open the C: Program Files>Java and make sure you see jre7 instead of jdk.
RS
Have a simpler solution:
Check your PATH. Most likely it is referring to incorrect java.exe. This started happening to me when I installed OS patch. In process of checkpoint etc, PATH got modified. Once I corrected it (using Environment Variables...), it worked immediately.
Try putting below line in your eclipse/STS -STS.ini file
-vm
C:\Program Files\Java\jdk1.8.0_121(your JDK version)\bin\javaw.exe
Put it at the top of the file.
Most probably it will work.
Sometimes putting javaw.exe in eclipse folder also work (where eclipse.exe is there)
This is an old post, but what solved my solution was editing the `eclispe.ini' file to include the correct path to the JDK.
Building off of what Lars answered, I did reinstall Java, so that may have been the source of the issue. Reglardless, this is the solution that worked for me. I did not have to delete any files from C:\windows\system32, however. I merely told eclipse to look in the new Java installation directory.
These docs indicated I needed to specify the path to the VM:
-vm
C:\Java\jdk1.7.0_25\bin\javaw.exe
This problem mainly occurs when we install new jre or jre gets updated automatically since jdk version and jre version are different and path variable i.e. JAVA_HOME contains jdk path with version included in it . Eclipse might be using that to generate the jre path name for the said file.
I did workaround i.e. changed name of jre folder to the older version e.g.
jre1.8.0_191 is after installing update and
jre1.8.0_60 was before update.
I renamed jre1.8.0_191 with jre1.8.0_60 to solve the issue
I had faced similar problem. Environment variable path problem
JAVA_HOME=C:\Program Files\Java\jdk1.8.0_192
Set the Environment variable after going
Control Panel\All Control Panel Items\System and select Advanced System Settings then set Environment Variables
In System Variables add a new variable JAVA_HOME and variable value = C:\Program Files\Java\jdk1.8.0_192, the path of the jdk file in your system.
and %JAVA_HOME%\bin in the path of the system variables.
Hopefully the problem will solve.
After doing this It works fine for me.
I have eclipse and I can test run java apps but I am not sure how to compile them. I read that I should type javac -version into my cmd.exe and see if it is recognized. It is not. So I went to sun's website and downloaded/installed JDK v6. Yet it still says 'javac' is an unrecognized command. What am I doing wrong?
Thanks!
UPDATE
OK after reading some replies it seems like what I am trying to do is create a .jar file that can be ran on another computer (with the runtime). However I am having trouble figuring out how to do that. This might be because I am using Flex Builder(eclipse), but I added the ability to create java projects as well.
Thanks
UPDATE
OK I do not want to make a JAR file, I am not trying to archive it...the whole point of making a program is to send it to users so they can use the program...THAT is what I am trying to do...why is this so hard?
To setup Eclipse to use the JDK you must follow these steps.
1.Download the JDK
First you have to download the JDK from Suns site. (Make sure you download one of them that has the JDK)
2.Install JDK
Install it and it will save some files to your hard drive.
On a Windows machine this could be in c:\program files\java\jdk(version number)
3.Eclipse Preferences
Go to the Eclipse Preferences -> Java -> Installed JREs
4.Add the JDK
Click Add JRE and you only need to located the Home Directory. Click Browse... and go to where the JDK is installed on your system. The other fields will be populated for you after you locate the home directory.
5.You're done
Click Okay. If you want that JDK to be the default then put a Check Mark next to it in the Installed JRE's list.
You don't need a separate compiler, eclipse already compiles the application for you. What you probably want to do is to create an "executable" JAR file, which you can do in eclipse by selecting File->Export->Runnable JAR file.
Note, however, that the resulting JAR file is not a "real" (i.e. Windows binary) executable - it still needs a JRE installed on the target computer. There isn't really a way to create windows binaries; that's not how Java works. On the upside, it will work without recompilation on a Linux or MacOS machine (if it has a JRE installed).
javac is located in the "bin" folder of your JDK installation. In order to run it you must either use full path or add this directory to your systems search path via the Control Panel.
If you installed to c:\program files\java\jdk1.6.0 your call will have to look like this:
c:\> "c:\program files\java\jdk1.6.0\bin\javac" -version
Umm, eclipse is an IDE, it compiles things as you go. You don't need javac.
If you have Eclipse installed and you can write new java apps from within it, your compilation should work already..
Eclipse automatically builds/compiles your system when you're saving new Java files. Just try to write a new simple Hello world app, printing something to the console (just type sysout and Ctrl+Space inside Eclipse)
Eclipse automatically compiles all project in the workspace. YOu can disable this option if you like under Project->Build Automatically.
A JAR file can function as an executable, when you export your project as a JAR file in Eclipse (as Michael Borgwardt pointed out) you can specify what's the executable class, that meaning which one has the entry point [aka public static void main(String[] args)]
If the user installed the JRE he/she can double-click it and the application would be executed.
EDIT: For a detailed explanation of how this works, see the "How do I create executable Java program?"
Eclipse to use the JDK you must follow these steps.
1.Download the JDK
First you have to download the JDK from oracle site.
Download link - > https://www.oracle.com/technetwork/es/java/javasebusiness/downloads/index.html
2.Install JDK
Install it and it will save some files to your hard drive. On a Windows machine this could be in c:\program files\java\jdk(version number)
3.Eclipse Preferences
Go to the Eclipse Preferences -> Java -> Installed JREs
4.Add the JDK
Click Add JRE and you only need to located the Home Directory. Click Browse... and go to where the JDK is installed on your system. The other fields will be populated for you after you locate the home directory.
5.You're done
Click Ok. If you want that JDK to be the default then put a Check Mark next to it in the Installed JRE's list.