ANT | Trying to override old definition of task javac Error

Question

i am trying to build a jar in ANT.Below is my code for generating jar file.i dont know why this error("Trying to override old definition of task javac") happens.sometimes its not generating jar.

<?xml version="1.0" ?> 
<project name="HelloWorld" default="compress">

    <presetdef name="javac">
            <javac includeantruntime="false" />
    </presetdef>

    <target name="init">
        <mkdir dir="build/classes" />
        <mkdir dir="dist" />
    </target>

    <target name="compile" depends="init">
        <javac srcdir="src" destdir="build/classes"/>
    </target>  

    <target name="compress" depends="compile">
            <jar destfile="dist/sample.jar" basedir="build/classes" />

    </target>

    <target name="execute" depends="compile">
        <java classname="src" classpath="build/classes" />
    </target> 

    <target name="clean">

    </target>

</project>

The output is as follows:

Buildfile: E:\GAD project\project\GAD\build.xml
Trying to override old definition of task javac
init:
    [mkdir] Created dir: E:\GAD project\project\GAD\dist
compile:
compress:
      [jar] Building jar: E:\GAD project\project\GAD\dist\sample.jar
BUILD SUCCESSFUL
Total time: 1 second

Let me know how can i rectify the error msg.?

Answer 1

lets try this

<presetdef name="my.javac">
            <javac includeantruntime="false" />
    </presetdef>


    <target name="compile" depends="init">
        <my.javac srcdir="src" destdir="build/classes"/>
    </target>