Using Ant's classpath in Eclipse - java

I have an Ant build.xml file that works just fine on the command line: it compiles, builds the JAR, and I am able to execute the main method from the JAR just fine. The build.xml file references several thirdparty libraries that are scattered here and there. When building the JAR, the script doesn't include all the thirdparty libraries into the JAR itself. Instead, it puts their path into the JAR's manifest. This helps to keep my JAR slim and tidy.
I'd like to be able to edit and debug my project in Eclipse, but I can't find an easy way to do so. I can have my project use the Ant file to build the project, and that seems to work. However, Eclipse is having trouble finding the thirdparty libaries, and thus Eclipse is having two problems:
it shows (in the text editor) lots of compile errors, because
lots of classes are undefined, and
it can't execute the JAR.
I can solve both of the above problems by specifying by hand, in two difference places (i.e., the build path via Properties->Java Build Path->Libraries, and the execution classpath via Run Configurations->Classpath), all the third party libraries. But it seems like I shouldn't have to do this manually, since all the third party libraries are already listed in my JAR's manifest. What am I doing wrong?
Here's my build.xml file:
<!-- Set global properties for this build -->
<property name="src" location="./src" />
<property name="build" location="./build"/>
<property name="dist" location="./dist"/>
<property name="logs" location="./logs"/>
<property name="docs" location="./docs"/>
<property name="jar" location="${dist}/dynamic_analyzer.jar"/>
<property name="lib" location="../../thirdparty/lib"/>
<property name="hive-util" location="../../hive-utils/dist"/>
<property name="hpdb" location="../../hive-db/hpdb/dist"/>
<property name="static" location="../../hive-backend/static_analyzer/dist"/>
<property name="mainclass" value="com.datawarellc.main.DynamicMain"/>
<path id="dep.runtime">
<fileset dir="${lib}" includes="**/*.jar"/>
<fileset dir="${hive-util}" includes="**/*.jar"/>
<fileset dir="${hpdb}" includes="**/*.jar"/>
<fileset dir="${static}" includes="**/*.jar"/>
</path>
<target name="clean">
<delete dir="${build}"/>
<delete dir="${dist}"/>
<delete dir="${docs}"/>
<delete dir="${logs}"/>
</target>
<target name="init">
<tstamp/>
<mkdir dir="${build}"/>
<mkdir dir="${dist}"/>
<mkdir dir="${logs}"/>
</target>
<target name="compile" depends="init">
<javac srcdir="${src}" destdir="${build}" debug="on" includeantruntime="false">
<classpath refid="dep.runtime" />
</javac>
<!-- Debug output of classpath -->
<property name="myclasspath" refid="dep.runtime"/>
<echo message="Classpath = ${myclasspath}"/>
</target>
<target name="jar" depends="compile">
<!-- Put the classpath in the manifest -->
<manifestclasspath property="manifest_cp" jarfile="${jar}" maxParentLevels="10">
<classpath refid="dep.runtime" />
</manifestclasspath>
<jar jarfile="${jar}" basedir="${build}">
<manifest>
<attribute name="Main-Class" value="${mainclass}"/>
<attribute name="Class-Path" value="${manifest_cp}"/>
</manifest>
<zipfileset dir="${src}" includes="**/*.xml" />
</jar>
</target>
You can see that I have third-party libraries in several directories (${lib}, ${hive-util}, ${hpdb}, and ${static}). I use these to create a path called dep.runtime. I then include dep.runtime in the manifest when building my jar. How can I get Eclipse to use the same dep.runtime for the build path and the classpath when executing?

An alternative to perl is to use an embedded groovy task:
<project name="demo" default="eclipse-files">
<property name="src.dir" location="src"/>
<property name="classes.dir" location="build/classes"/>
<path id="dep.runtime">
<fileset dir="${lib}" includes="**/*.jar"/>
<fileset dir="${hive-util}" includes="**/*.jar"/>
<fileset dir="${hpdb}" includes="**/*.jar"/>
<fileset dir="${static}" includes="**/*.jar"/>
</path>
<target name="bootstrap">
<mkdir dir="${user.home}/.ant/lib"/>
<get dest="${user.home}/.ant/lib/groovy-all.jar" src="http://search.maven.org/remotecontent?filepath=org/codehaus/groovy/groovy-all/2.1.4/groovy-all-2.1.4.jar"/>
</target>
<target name="eclipse-files">
<taskdef name="groovy" classname="org.codehaus.groovy.ant.Groovy"/>
<groovy>
import groovy.xml.MarkupBuilder
project.log "Creating .classpath"
new File(".classpath").withWriter { writer ->
def xml = new MarkupBuilder(writer)
xml.classpath() {
classpathentry(kind:"src", path:properties["src.dir"])
classpathentry(kind:"output", path:properties["classes.dir"])
classpathentry(kind:"con", path:"org.eclipse.jdt.launching.JRE_CONTAINER")
project.references."dep.runtime".each {
classpathentry(kind:"lib", path:it)
}
}
}
</groovy>
</target>
<target name="clean">
<delete file=".classpath"/>
</target>
</project>
Notes:
The bootstrap target will download the 3rd party groovy jar (No dependency on perl)
Groovy can access the "dep.runtime" ANT path directly and iterate over its contents
Groovy has excellent support for writing XML files.
The following answer is similar and additionally generates the Eclipse .project file.
Using Apache Ivy with netbeans

I came up with the following workaround, inspired by the link provided by #leeand00.
First, I wrote a simple Perl script (called genClasspath.pl) that generates the .classpath file that Eclipse uses.
#!/usr/bin/perl
use strict;
if (#ARGV != 2) {
print STDERR "Usage: $0 OUTFILE CLASSPATHSTRING\n";
print STDERR "e.g., $0 .classpath path1:path2:path3\n";
exit 1;
}
my $OUTFILE = $ARGV[0];
my $CLASSPATHSTRING = $ARGV[1];
open my $out_fh, '>', $OUTFILE or die "Couldn't open output file: $!";
print $out_fh q{<?xml version="1.0" encoding="UTF-8"?>
<classpath>
<classpathentry kind="src" path="src"/>
<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
<classpathentry kind="output" path="build"/>
};
my #libs = split(":", $CLASSPATHSTRING);
foreach my $thisLib (#libs){
print $out_fh " <classpathentry kind=\"lib\" path=\"$thisLib\"/>\n";
}
print $out_fh "</classpath>\n";
Then, I have my build.xml file call this script with the content of dep.runtime:
<target name="compile" depends="init">
<javac srcdir="${src}" destdir="${build}" debug="on" includeantruntime="false">
<classpath refid="dep.runtime" />
</javac>
<property name="myclasspath" refid="dep.runtime"/>
<exec dir="." executable="../../scripts/genClasspath.pl" os="Linux">
<arg value=".classpath"/>
<arg value="${myclasspath}"/>
</exec>
</target>
The only catch is that I need to run Ant on the command line at least once before I open the project in Eclipse. But when I do, Eclipse is able to compile and execute my project just fine, since the classpath is exactly the same as Ant's.

Related

Problems with Ant build.xml configuration to work with external Libraries and Java property files

I have a problem with Ant Build Tool.
First, below you can see my project structure:
and the content of my build.xml file is:
<?xml version="1.0" encoding="UTF-8"?>
<project name="addonGenerator" default="main" basedir=".">
<property name="projectName" value="addonGenerator"/>
<property name="src.dir" location="src"/>
<property name="build.dir" location="bin"/>
<property name="dist.dir" location="dist"/>
<target name="compile" description="compile the source ">
<mkdir dir="${build.dir}"/>
<javac srcdir="${src.dir}" destdir="${build.dir}">
<classpath>
<pathelement path="lib/velocity-1.7.jar"/>
<pathelement path="lib/log4j-1.2.16.jar"/>
</classpath>
</javac>
</target>
<target name="dist" description="package, output to JAR">
<mkdir dir="${dist.dir}"/>
<jar jarfile="${dist.dir}/${projectName}.jar" basedir="${build.dir}">
<zipgroupfileset dir="lib" includes="velocity-1.7.jar" />
<zipgroupfileset dir="lib" includes="log4j-1.2.16.jar" />
<manifest>
<attribute name="${projectName}" value="main"/>
<attribute name="Main-Class" value="main.java.AddonGenerator"/>
</manifest>
</jar>
</target>
<target name="clean" description="clean up">
<delete dir="${build.dir}"/>
<delete dir="${dist.dir}"/>
</target>
<target name="main" depends="clean, compile, dist"/>
</project>
I don't know how setup the Ant build.xml to build and run my project with external libraries and the java property file generator.properties
To include your generator.properties file in the .jar file, add your resources directory when building the .jar:
<jar jarfile="${dist.dir}/${projectName}.jar" basedir="${build.dir}">
<fileset dir="src/main/java/resources"/>
Since you are currently building a “fat jar” (by directly including the contents of your library .jars in your application .jar), you can run by simply invoking your .jar file. Such a target obviously requires the .jar file to be built, so it makes sense to depend on the "dist" target:
<target name="run" depends="dist">
<java jar="${dist.dir}/${projectName}.jar"/>
</target>
On another note, I don’t think you want to pass src as your source directory, unless your classes actually declare themselves with ‘package main.java;’ (which they shouldn’t). You should pass the actual root of your packages to the javac task:
<property name="src.dir" location="src/main/java"/>
You should also make the "dist" target depend on "compile", since, well, it depends on having compiled classes available.
I also would suggest that your default target, "main", avoid calling the "clean" target. You should not clean before every single build; that defeats one of the most useful benefits of Ant, namely the ability to update only the things that need to be updated. You should only clean when you need to, with a command like ant clean compile or simply ant clean.
Note that once "dist" depends on "compile", and once "main" no longer calls "clean", you can simply remove the "main" target and change your project’s default target to "dist". When you think about it, this makes sense: the default action is to build and package the application.

Need to make a ant build file for eclipse project

I have a simple game implemented in eclipse. It consists of about 8 classes.
It is for my school assignment.
In the turn in specification, there is written:
"Send me all source codes, documentation and ant build file, which allows the project to be compiled and generate javadoc documentation".
I really do not understand how ant works. I googled some tutorials, but I cannot understand them either. I tried to generate build.xml file in eclipse, but the teacher said that this doesnt work either.
Could someone give me some simple steps or give me link to some really basic tutorial? Thanks for help.
This is the eclipse generated ant (export project as antbuildfile):
And it is kind of weird, because the class BasicPaint I deleted a long time ago.
<?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="Snakes_and_Adders">
<property environment="env"/>
<property name="debuglevel" value="source,lines,vars"/>
<property name="target" value="1.8"/>
<property name="source" value="1.8"/>
<path id="Snakes_and_Adders.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="Snakes_and_Adders.classpath"/>
</javac>
</target>
<target description="Build all projects which reference this project. Useful to propagate changes." name="build-refprojects"/>
<target name="BasicPaint">
<java classname="snakes_and_adders.BasicPaint" failonerror="true" fork="yes">
<classpath refid="Snakes_and_Adders.classpath"/>
</java>
</target>
<target name="Game">
<java classname="snakes_and_adders.Game" failonerror="true" fork="yes">
<classpath refid="Snakes_and_Adders.classpath"/>
</java>
</target>
<target name="NewGame">
<java classname="snakes_and_adders.NewGame" failonerror="true" fork="yes">
<classpath refid="Snakes_and_Adders.classpath"/>
</java>
</target>
<target name="PaintingExample">
<java classname="snakes_and_adders.PaintingExample" failonerror="true" fork="yes">
<classpath refid="Snakes_and_Adders.classpath"/>
</java>
</target>
Ant is used to perform tasks that are useful to build applications. You have tasks like <javac> <jar> etc.. To compile your classes and put them in a jar file.
I don't see why the build.xml generated file wouldn't work.. But you can take it as an example to understand how ant works. You can also adapt that build.xml file to make it work anywhere.
This tutorial looks well explained at first sight: http://www.javaworld.com/article/2076208/java-app-dev/automate-your-build-process-using-java-and-ant.html
I find that ant can be pretty complex easily, it'll take you time to understand it well but it's really doable.

Ant creating WAR JAVA

Good day!
I have been trying to write ant file for compilation and making the WAR file for a long time.
But still it doesnt work. At this time I have no build errors, but there is a Tomcat "Resource not found" error, where should be my servlet.
Here is my build.xml:
<?xml version="1.0" ?>
<property environment="env"/>
<property name="dir.src" value="src"/>
<property name="dir.dist" value="ant-dist"/>
<property name="dir.lib" value="WebContent/WEB-INF/lib"/>
<property name="dir.build" value="ant-build"/>
<property name="dir.classes" value="${dir.build}/classes"/>
<property name="tomcat-home" value="${env.TOMCAT_HOME}"/>
<property name="java-home" value="${env.JAVA_HOME}"/>
<path id="compile.classpath">
<fileset dir="${dir.lib}" includes="*.jar"/>
<fileset dir="${tomcat-home}" includes="**/*.jar" />
<fileset dir="${java-home}" includes="**/*.jar" />
</path>
<target name="init">
<mkdir dir="${dir.classes}"/>
<mkdir dir="${dir.dist}" />
</target>
<target name="compile" depends="init" >
<javac destdir="${dir.build}" debug="true" srcdir="${dir.src}" includeantruntime="false">
<classpath refid="compile.classpath"/>
</javac>
</target>
<target name="war" depends="compile">
<war destfile="${dir.dist}/SoulVoxServer.war" needxmlfile="false">
<fileset dir="WebContent"/>
<lib dir="${dir.lib}"/>
<classes dir="${dir.classes}"/>
</war>
</target>
<target name="clean">
<delete dir="${dir.dist}" />
<delete dir="${dir.build}" />
</target>
I thought that the problem can depend on web.xml file missing, but i use annotation so it should work anyway, isn't it?
Thank you!
EDIT
I found that my war file doesnt contain any classes. Its structure:
+META-INF
--MANIFEST.MF
+WEB-INF
--classes (It is empty)
--lib (here goes my jar files. Its ok)
-Playlist.jsp
EDIT
I solved that problem and now i see the next:
I have 2 war files:
1) Generated by ant. 13.3 Mb. Doesnt work.
2) Generated by eclipse and has the same files inside (after jar -xvf), but it is only 6.6 Mb size.. Thi one works.
What is that?

NoClassDefFound error for a jar created using ant build

I have a java project with class having main method in package com.nik.mypackage. Only one library is referenced which is someLib-5.0.2.jar
This library is in lib folder in eclipse and added to the build path.
I am creating executable jar of the application using the below ant script target:
<property name="src" location="src"/>
<property name="build" location="build"/>
<property name="dist" location="dist"/>
<target name="init">
<tstamp/>
<mkdir dir="${build}"/>
</target>
<target name="compile" depends="init"
description="compile the source " >
<javac srcdir="${src}" destdir="${build}">
<classpath>
<pathelement path="${classpath}"/>
<pathelement location="lib/someLib-5.0.2.jar"/>
</classpath>
</javac>
</target>
<target name="dist" depends="compile" description="generate the distribution" >
<!-- Create the distribution directory -->
<mkdir dir="${dist}/lib"/>
<copy todir="${build}/lib" verbose="true" file="lib/someLib-5.0.2.jar" />
<!-- Put everything in ${build} into the MyProject-${DSTAMP}.jar file -->
<jar jarfile="${dist}/lib/myProject-${DSTAMP}.jar" basedir="${build}">
<manifest>
<attribute name="Main-Class" value="com.nik.mypackage.MainClass"/>
<attribute name="Class-Path" value="../lib/someLib.jar"/>
</manifest>
</jar>
</target>
The jar MyProject-20111126.jar is getting created. However, running the below command:
c:>java -jar MyProject-20111126.jar
is throwing a NoClassDefFoundError for a class in someLib.jar
What am I doing wrong ??
Thanks for reading!
When you run where is someLib.jar relative to the MyProject-20111126.jar?
The classpath you are setting up in the MyProject.jar is telling the VM to look for a lib folder in the parent directory of MyProject.jar.
The ClassPath entry in the manifest is interpreted relative to the location of the JAR file. It is used to locate jar files on the File System. The regular class loader in JAVA does not support JAR files bundled inside of JAR files.
As mentioned in the comment by Eric Rosenberg, we can not nest jar files inside other jar files. So we need to deflat the library and bundle individual classes in the app jar.

Ant built does not generate class files

I'm using build.xml to build my src. However it failed to generate class files without any error message. The full script is
<?xml version="1.0"?>
<project name="auxiliary" basedir="." default="dist">
<property name="src.dir" value="../auxiliary-src/com/nextbio/drugbank"/>
<property name="dist.dir" value="dist"/>
<property name="lib.dir" value="../jboss_config/common_app_jars"/>
<property name="temp.dir" value="temp"/>
<property name="foo_dist.dir" value="../foo/dist"/>
<path id="libs-classpath">
<fileset dir="${foo_dist.dir}">
<include name="foo.jar"/>
</fileset>
</path>
<target name="dist" depends="auxiliary-dist" />
<target name="auxiliary-cleanup">
<delete dir="${temp.dir}"/>
<delete dir="${dist.dir}"/>
<echo message="cleaned up. ${temp.dir}, and ${dist.dir} have been deleted."/>
</target>
<target name ="auxiliary-dist">
<delete dir="${temp.dir}"/>
<echo message="delete ${temp.dir}" />
<mkdir dir="${temp.dir}"/>
<javac destdir="${temp.dir}" source="1.6" target="1.6" debug="on" fork="true" memorymaximumsize="1024m">
<src path="${src.dir}"/>
<classpath>
<path refid="libs-classpath"/>
</classpath>
<include name="com/car/**"/> <!-- troubled line -->
</javac>
<!--<copy overwrite="true" todir="${temp.dir}">
<fileset dir="${src.dir}">
<exclude name="**/*.java"/>
<exclude name="**/*.sql"/>
<exclude name="**/*.txt"/>
</fileset>
</copy>
<delete dir="${dist.dir}"/>
<mkdir dir="${dist.dir}"/>
<jar destfile="${dist.dir}/auxiliary.jar" basedir="${temp.dir}"/> -->
</target>
There is no class file in ${temp.dir} after this step, and no error message. I double checked it, and found it is because of the "troubled line". I tried to add some files to the classpath. I don't know why it is wrong.
The source path should point to the root of the package tree. You make it point to a specific package inside the sources : ../auxiliary-src/com/nextbio/drugbank.
And in the javac task, you ask it to compile all the files matching the pattern com/car/**. That means that it will compile the Java source files in ../auxiliary-src/com/nextbio/drugbank/com/car or in a subdirectory. If that's the case, you have very unconventional package names.
I had the same problem.
My project complilated well but the classes there weren't in nowhere and It didn't have any error message.
My problem was the classpath. The eclipse wizard added EclipseLink 2.5.1 jars.
I removed it and the problem is gone.
I suggest make a simple HelloWord and remove all jars
reference from the classpath and try again.
I encountered this "ant, javac, compile" problem related with the classpath to.
No debug or verbose message shown.
This behavior appear because in classpath exists not compatible (superior) version jar packages and that cause no output classes.

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