The error was in the build.xml script.
I was working with the generated build.xml that Eclipse provides:
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!-- WARNING: Eclipse auto-generated file.
Any modifications will be overwritten.
To include a user specific buildfile here, simply create one in the same
directory with the processing instruction <?eclipse.ant.import?>
as the first entry and export the buildfile again. --><project basedir="." default="build" name="ci-research-teamcity-test-project">
<property environment="env"/>
<property name="ECLIPSE_HOME" value="../../../../eclipse/"/>
<property name="debuglevel" value="source,lines,vars"/>
<property name="target" value="1.8"/>
<property name="source" value="1.8"/>
<path id="ci-research-teamcity-test-project.classpath">
<pathelement location="bin"/>
</path>
<target name="init">
<mkdir dir="bin"/>
<copy includeemptydirs="false" todir="bin">
<fileset dir="src">
<exclude name="**/*.java"/>
</fileset>
</copy>
</target>
<target name="clean">
<delete dir="bin"/>
</target>
<target depends="clean" name="cleanall"/>
<target depends="build-subprojects,build-project" name="build"/>
<target name="build-subprojects"/>
<target depends="init" name="build-project">
<echo message="${ant.project.name}: ${ant.file}"/>
<javac debug="true" debuglevel="${debuglevel}" destdir="bin" includeantruntime="false" source="${source}" target="${target}">
<src path="src"/>
<classpath refid="ci-research-teamcity-test-project.classpath"/>
</javac>
</target>
<target description="Build all projects which reference this project. Useful to propagate changes." name="build-refprojects"/>
<target description="copy Eclipse compiler jars to ant lib directory" name="init-eclipse-compiler">
<copy todir="${ant.library.dir}">
<fileset dir="${ECLIPSE_HOME}/plugins" includes="org.eclipse.jdt.core_*.jar"/>
</copy>
<unzip dest="${ant.library.dir}">
<patternset includes="jdtCompilerAdapter.jar"/>
<fileset dir="${ECLIPSE_HOME}/plugins" includes="org.eclipse.jdt.core_*.jar"/>
</unzip>
</target>
<target description="compile project with Eclipse compiler" name="build-eclipse-compiler">
<property name="build.compiler" value="org.eclipse.jdt.core.JDTCompilerAdapter"/>
<antcall target="build"/>
</target>
<target name="Demo01">
<java classname="pack1.Demo01" failonerror="true" fork="yes">
<classpath refid="ci-research-teamcity-test-project.classpath"/>
</java>
</target>
<target name="Demo02">
<java classname="pack1.Demo02" failonerror="true" fork="yes">
<classpath refid="ci-research-teamcity-test-project.classpath"/>
</java>
</target>
</project>
Here's my build_custom.xml that works, it's trimmed down and simplified:
(note the compiler="modern" attribute in the javac task, this fixed another error I got, namely Compilation error: javac - Class not found: javac1.8)
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!-- Author: Petrus K.
Description: A custom ant build script based on an auto-generated script by Eclipse 4.4.0
More info: http://ant.apache.org/manual/using.html
-->
<!-- project attributes -->
<project basedir="." default="build" name="ci-research-teamcity-test-project">
<description>
simple ant build script for demonstrational purposes
</description>
<!-- properties -->
<property name="src" location="src"/>
<property name="bin" location="bin"/>
<!-- paths -->
<path id="classpath">
<pathelement location="bin"/>
</path>
<!-- targets -->
<!-- TARGET init: initializes file and folder structures before compilation -->
<target name="init" description="initializes file and folder structures before compilation">
<mkdir dir="bin"/>
<copy includeemptydirs="false" todir="bin">
<fileset dir="src">
<exclude name="**/*.java"/>
</fileset>
</copy>
<echo message="init completed"></echo>
</target>
<!-- TARGET build: compiles the source -->
<target name="build" depends="init" description="compiles the source">
<javac srcdir="${src}" destdir="${bin}" includeantruntime="false" compiler="modern"/>
<echo message="build completed"></echo>
</target>
<!-- TARGET clean: cleans the compiled files -->
<target name="clean" description="cleans the compiled files">
<delete dir="bin"/>
<echo message="clean completed"></echo>
</target>
<!-- TARGET run: runs the demo project -->
<target name="run" depends="build" description="runs the demo project">
<java classname="pack1.Demo01" failonerror="true" fork="yes">
<classpath refid="classpath"/>
</java>
<echo message="run completed"></echo>
</target>
</project>
