How do I change the JAVA HOME for ant

Question

I m doing java work on a class server where I don t have root  Whenever I try to compile using ant  it points to the wrong directory   usr tomcat instead of  usr tomcat jre      One of the things we were told to do when setting up our user accounts was to add export JAVA HOME  usr tomcat jre to the  bashrc file  I don t know if that was supposed to take care of the problem but it doesn t seem to   So  how can I change the JAVA HOME property for ant but only for when I run ant   EDIT   echo  JAVA HOME points to  usr tomcat jre echo  JAVA HOME bin points to  usr tomcat jrebin  The problem is when I normally run ant I get this error   Unable to locate tools jar  Expected to find it in  usr tomcat lib tools jar Buildfile  build xml  compile       javac  Compiling 1 source file to  home ejm244 build classes  BUILD FAILED  home ejm244 build xml 9  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  Total time  0 seconds

User · Answer

JAVA HOME should point at where the JDK is installed not not a JRE   So  if you type ls  JAVA HOME what do you see  if you do ls  JAVA HOME bin  do you see javac   If the first doesn t work then you don t have JAVA HOME pointing at the right directory  If the second doesn t work then you need to point JAVA HOME at a JDK instead of a JRE

User · Answer

Set the JRE in the project  project properties -  Java Build Path-  Libraries  typically last entry   or global default in preferences  Java- Installed JREs  to a JDK  not a JRE

User · Answer

JAVA HOME needs to point to a JDK home if you re trying to compile code  Check to see if   usr tomcat jre bin javac  exists  I doubt it does   If you don t have a JDK  then you can work around it by getting the ECJ  eclipse compiler  library  dropping it into     ant lib  and adding a system property to the command-line to use that compiler - check the Ant manual for details   http   ant apache org

User · Answer

try with this    usr sbin update-alternatives --config java

User · Answer

There are 2 ways of changing the compiler   export JAVA HOME  path to jdk before you start Ant  Set  lt javac exectuable  quot  path to javac quot  gt   Another option would be to add a respective tools jar to the classpath  but this is usually used if Ant is started from another tools like Maven  For more details on these  or other  options of changing Java Compiler in Ant  see this article for example

User · Answer

Looking at the shell script for invoking ant  it is possible that the value for  JAVA HOME set for your shell in  bashrc can be overridden in the files  etc ant conf   HOME  ant ant conf  and  HOME  antrc  If you execute bash -x  lt path to ant script gt  it will emit debugging information which should help you track down where  JAVA HOME is being overridden

User · Answer

java home always points to the jdk  the compiler that gave you the classes  and the jre is thw way that your browser or whatever will the compiled classes so it must have matching between jdk and jre in the version

User · Answer

You could create your own script for running ant  e g  named ant sh like      bin sh JAVA HOME  lt  path to jdk gt   export JAVA HOME ant      and then run your script     chmod 755 ant sh    ant sh clean compile   or whatever ant target you wish to run

User · Answer

On my Windows 7 machine setting    JAVA HOME  C  Program Files Java jdk1 6 0 18     didn t work  But setting    JAVA HOME C  Program Files Java jdk1 6 0 18   worked

User · Answer

When running ant from the shell  you don t need to export JAVA HOME first  which would set that variable for your current shell and all future commands  instead use  user host    JAVA HOME  path to jdk ant targets

User · Answer

Though the environment variable JAVA HOME set correctly  the ant may use the configured JRE within the each build xml or any build files    To check what version of the JRE the ant is using  right click on the build file -  select the build ant which displays the details about the tasks to choose etc  select the JRE which you want to use    Its advisable to use the project level settings or just at the workspace level

User · Answer

Set the env var   JAVACMD - full path of the Java executable  Use this to invoke a different JVM than JAVA HOME bin java  exe    Reference  http   ant apache org manual running html

User · Answer

When using Bash just try this     export JAVA HOME  usr tomcat jre

User · Answer

You will need to change JAVA HOME path to the Java SDK directory instead of the Java RE directory  In Windows you can do this using the set command in a command prompt   e g   set JAVA HOME  C  Program Files Java jdk1 6 0 14

[ant] How do I change the JAVA_HOME for ant?

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