I am trying to follow a tutorial about how to use ant to build and run your application. I've followed all the steps and have created the build file, but when I try to run ant it gives me this error.
BUILD FAILED /home/bilal/tmp/ant/build.xml:19: 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 "/usr/lib/jvm/java-6-openjdk/jre"
Any ideas how to resolve this issue ?
Make JAVA_HOME variable point to a jdk installation, not jre.
You are referencing the runtime environment, not the development kit - it can't find the compiler because its not there.
From the line you posted, which states you have open-jdk you can just remove the jre at end:
export JAVA_HOME='/usr/lib/jvm/java-6-openjdk/'
This is by design. You cannot use ant's java.home (which is a java.lang.System property) interchangeably with how JAVA_HOME is set in the OS environment. You are probably trying to assert the location of the Java compiler with a fundamentally different value from a different property layer -- i.e. java.home (from Ant's Java internals) points to the Java Runtime Environment at <any_installed_java_pointed_to_by_ant>/jre while JDK_HOME (from the OS environment) is usually set to <DOWNLOADED_AND_INSTALLED_JAVA_DEVELOPMENT_KIT>.
See my question and answer here for more details: Where does Ant set its 'java.home' (and is it wrong) and is it supposed to append '/jre'?
The solution is to access the system environment property within Ant by using ${env.JAVA_HOME}. Specify which java to use explicitly in the Javac Task by setting the executable property to the javac path and the fork property to yes (see Ant's Javac Task Documentation). That way, it doesn't matter what Java environment Ant is running inside, the compiler is always clearly specified!
I know this question is old but the accepted answer does not work anymore and since this is the fist link on google search i'll tell how i solved this problem.
for eclipse using ubuntu:
go to Window->Preferences->Ant->Runtime->Select Ant_Home_Entries and click on add external jars then find in file explorer where your jdk is (default is in /usr/lib/jvm/) and in the lib folder of your jdk you will find the tool.jar. select this one and click apply.
try to build your project and things should work!
note: i hadn't used ant for a long time but needed it for ycsb couchbase workload generator (http://www.couchbase.com/wiki/display/couchbase/Load+Generator+Setup) if anyone is/was stuck on this.
I am using Windows 7 and have struggled with the same issue. I fixed it by changing my environment variables.
To change your environment variables click here
I added ";%JAVA_HOME%/bin" to the end of paths variable and added a new "JAVA_HOME" variable and set its value to the location of my JDK "C:\Program Files\Java\jdk1.8.0_11". After that I restarted my Node.js command prompt and it worked.
Please note you JDK directory may be different then mine. Also depending on your setup, you may need to restart you computer after setting the environment variables.
I had a similar problem and it turned out the issue was having both versions 6 & 7 of OpenJDK. The answer comes from r-senior on ubuntu forums (http://ubuntuforums.org/showthread.php?t=1977619) --- just uninstall version 6:
sudo apt-get remove openjdk-6-*
make sure that JAVA_HOME and CLASSPATH aren't set to anything since that isn't actually the problem.
Experienced this issue when trying to run the android emulator with Meteor 1.0 on elementary OS Luna (based on Ubuntu 12.04 LTS sources).
openjdk-6-jdk was installed, as well as the jre. In the end, not expecting any success, I tried:
sudo apt-get remove openjdk-6-*
this resulted in fully expected errors, so I followed up with
sudo apt-get install openjdk-6-jdk
and things worked. Go figure.
Under Jenkins it complains like :
/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64/ doesn’t look like a JDK directory
Reason : Unable to found any Dev Kit for JDK.
Solution:
Please make sure to install openjdk-devel package as well along with your JDK-1.8* version and reexport with : # source ~/.bash_profile
