Ant with -Xlint:unchecked

I use ant 1.9.4 and jdk1.8,my build.xml file is follows:

 

<?xml version="1.0" encoding="UTF-8" ?>

<project name="demo" default="run" basedir=".">

<property name="src" value="src"/>

<property name="lib" value="src/lib"/>

<property name="dest" value="WEB-INF/classes"/>

<property name="dest_lib" value="WEB-INF"/>

<path id="Third-Part Lib">

         <fileset dir="${lib}">

       <include name="*.jar" />

         </fileset>

</path>

<target name="init">  

         <mkdir dir="${dest}"/>  

</target>

<target name="compile" depends="init">

         <javac srcdir="${src}" destdir="${dest}">

                   <classpath refid="Third-Part Lib"/>

         </javac>   

</target>

<target name="build" depends="compile">

         <mkdir dir="${dest}"/>

         <javac srcdir="${src}" destdir="${dest}" target="1.8" debug="true"
deprecation="true" optimize="false" failonerror="true"
includeantruntime="false"><compilerarg value="-Xlint:unchecked"/></javac>

         <copy todir="${dest}" preservelastmodified="true">

         </copy>

</target>

<target name="run" depends="build">

         <java classname="demo.StudentTest">

                   <classpath refid="Third-Part Lib"/>

         </java>

</target>

<target name="clean">

         <delete dir="${dest}" />  

</target>

<target name="rerun" depends="clean,run">  

         <ant target="clean" />  

         <ant target="run" />  

</target>  

</project>

 

when I use ant build to compile java file,it raise following warning
message:

compile:

    [javac] E:\tomcat\webapps\demo\build.xml:17: warning:
'includeantruntime' was not set, defaulting to build.sysclasspath=last; set
to false for repeatable builds

    [javac] Compiling 13 source files to
E:\phoenix\webapps\phoenix\WEB-INF\classes

    [javac] Waring: E:\tomcat\webapps\demo\src\demo\StudentTest.java using
or overwrite old API

[javac] Waring: For detail information, Please use -Xlint:deprecation to
compile

 

I have used <compilerarg value="-Xlint:unchecked"/> in <javac>, why ant
still raise above information? How can I get which API is old?  I am puzzled
it for several days. How to make -Xlint:deprecation to work? 

PS: How to set 'includeantruntim'?

 

Thanks.