How to change Ant compiler to JDK 1.6

Question

I need to compile my source code to be compatible with jre 1.6. However, when I attempt to set the compiler attribute of the javac task to be javac1.6, ant will still compile my code with javac1.7. I have also tried setting the compiler version to be "modern" and that did not help.

<target name="compile-tests">
    <javac compiler="javac1.6" includeantruntime="false" srcdir="${test.dir}"
     destdir="${build.dir}" >
        <classpath refid="class.path" />
    </javac>
</target>

My JAVA_HOME is set to JDK 1.6:

echo $JAVA_HOME </code> gives: <code>
/usr/lib/jvm/java-6-openjdk-amd64/

My ant version is: Apache Ant(TM) version 1.8.2

According to this post, ant uses its own compiler. How do I override the ant default? Also, according to this post and the ant documentation, I can set the global build.compiler property. What do I set that property to be and how might I do that?

Answer 1

In the javac task, try specifying the Java compiler by setting the executable attribute as follows:

<property name="JDK1.6.dir" location="/usr/lib/jvm/java-6-openjdk-amd64" />
<property name="javac1.6" location="${JDK1.6.dir}/bin/javac" />

<target name="compile-tests">
  <javac executable="${javac1.6}" 
      fork="yes"
      includeantruntime="false" 
      srcdir="${test.dir}"
      destdir="${build.dir}" >
    <classpath refid="class.path" />
  </javac>
</target>