Re: the classes in rt.jar cannot be found during ant build

From:

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>

Newsgroups:

comp.lang.java.programmer

Date:

Mon, 02 Apr 2012 20:53:22 -0400

Message-ID:

<4f7a4a06$0$287$14726298@news.sunsite.dk>

On 4/2/2012 8:16 PM, zyng wrote:

Below is a more completed build.xml. The error message

compile:
     [javac] C:\my_work\build.xml:47: warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to fals
  for repeatable builds
     [javac] Compiling 407 source files to C:\my_work\build
     [javac] C:\my_work\src\abc\efg\xml\MyXmlUtils.java:27: package com.sun.xml.internal.fastinfoset.stax does not exist
     [javac] import com.sun.xml.internal.fastinfoset.stax.StAXDocumentParser;
     [javac] ^
     [javac] C:\my_work\src\abc\efg\xml\MyXmlUtils.java:28: package com.sun.xml.internal.fastinfoset.stax does not exist
     [javac] import com.sun.xml.internal.fastinfoset.stax.StAXDocumentSerializer;
     [javac] ^
     [javac] C:\my_work\src\abc\efg\xml\MyXmlUtils.java:29: package com.sun.xml.internal.txw2.output does not exist
...

Those packages are located inside rt.jar. (I use Eclipse and I include rt.jar in the project property, so there is no compiling error in Eclipse).

Those packages are not intended to be used in your code.

You should use the documented API's.

Another observation (only happens in my office computer, not in my home computer) confuses me is that: when I copy rt.jar to rt2.jar which locates in the same directory(C:\Program Files\Java\jdk1.6.0_24\jre\lib) and modify build.xml a bit:
         <fileset dir="${env.JAVA_HOME}">
                 <include name="jre/lib/rt2.jar"/>
         </fileset>

Then ant works! Very confusing. I just re-tested this observation in my home computer and it does not work -- same error message. But this approach does work in my office computer.

<project name="myproject" default="compile" basedir=".">
    <property environment="env"/>
    <property name="build.dir" location="build"/>
    <property name="libs.dir" location="../libs"/>
    <property name="externals.dir" location="${libs.dir}/external"/>
    <property name="install.dir" location="${libs.dir}/installed"/>

    <path id="project.classpath">
         <fileset dir="${env.JAVA_HOME}">
                 <include name="jre/lib/rt.jar"/>
         </fileset>
        <pathelement location="${build.dir}"/>
        <fileset dir="${externals.dir}">
            <include name="abc.jar"/>
            <include name="xyz.jar"/>
            <include name="junit.jar"/>
        </fileset>
    </path>

    <target name="compile">
        <javac srcdir="${src.dir}" destdir="${build.dir}" compiler="modern" fork="yes" debug="on">
            <classpath refid="project.classpath"/>
            <compilerarg value="-Xlint"/>
        </javac>
    </target>
</project>

You should not explicitly ref rt.jar!

Arne