How to build a Java app with gradle and jlink?

Question

Sorry if this questions seems very lost but I am. I created a simple Java 18 Swing application that could be compiled into a jar for distribution. However, I read that this is no longer the preferred way of distributing so I added gradle to my project and tried building with jlink. But whenever I execute the jlink task I get an error which makes no sense to me. Can someone tell me what I'm doing wrong?

build.gradle:

plugins {
    id 'application'
    id 'java'
    id 'idea'
    id "org.beryx.jlink" version "2.25.0"
}

repositories {
    mavenCentral()
}

dependencies {
    implementation 'com.google.guava:guava:30.1.1-jre'
    implementation 'org.jopendocument:jOpenDocument:1.3'
    implementation 'org.odftoolkit:odfdom-java:0.8.7'
}

application {
    mainClass = 'miq.converter.App'
}

task wrapper(type: Wrapper){
    gradleVersion = '7.2'
}

jar {
    manifest {
        attributes(
                'Main-Class': 'miq.converter.App'
        )
    }
}
jlink {
    launcher {
        name = 'MIQ-Converter'
    }
}

Folder structure:

│   .gitattributes
│   .gitignore
│   gradlew
│   gradlew.bat
│   settings.gradle
│
├───.gradle
│
├───app
│   │   build.gradle
│   │   gradlew
│   │   gradlew.bat
│   │
│   ├───gradle
│   │   └───wrapper
│   │           gradle-wrapper.jar
│   │           gradle-wrapper.properties
│   │
│   └───src
│       └───main
│           ├───java
│           │   └───miq
│           │       └───converter
│           │               App.java
│           │
│           └───resources
└───gradle
    └───wrapper
            gradle-wrapper.jar
            gradle-wrapper.properties

module-info.java

open module miq.converter.merged.module {
    exports com.google.common.annotations;
    exports com.google.common.base;
    exports com.google.common.base.internal;
    exports com.google.common.cache;
    exports com.google.common.collect;
    exports com.google.common.escape;
    exports com.google.common.eventbus;
    exports com.google.common.graph;
    exports com.google.common.hash;
    exports com.google.common.html;
    exports com.google.common.io;
    exports com.google.common.math;
    exports com.google.common.net;
    exports com.google.common.primitives;
    exports com.google.common.reflect;
    exports com.google.common.util.concurrent;
    exports com.google.common.util.concurrent.internal;
    exports com.google.common.xml;
    exports com.google.errorprone.annotations;
    exports com.google.errorprone.annotations.concurrent;
    exports com.google.j2objc.annotations;
    exports com.google.thirdparty.publicsuffix;
    exports com.sun.script.ognl;
    exports edu.umd.cs.findbugs;
    exports edu.umd.cs.findbugs.annotations;
    exports javax.annotation;
    exports javax.annotation.concurrent;
    exports javax.annotation.meta;
    exports javax.xml;
    exports javax.xml.datatype;
    exports javax.xml.namespace;
    exports javax.xml.parsers;
    exports javax.xml.transform;
    exports javax.xml.transform.dom;
    exports javax.xml.transform.sax;
    exports javax.xml.transform.stream;
    exports javax.xml.validation;
    exports javax.xml.xpath;
    exports net.jcip.annotations;
    exports ognl;
    exports org.apache.commons.collections;
    exports org.apache.commons.collections.bag;
    exports org.apache.commons.collections.bidimap;
    exports org.apache.commons.collections.buffer;
    exports org.apache.commons.collections.collection;
    exports org.apache.commons.collections.comparators;
    exports org.apache.commons.collections.functors;
    exports org.apache.commons.collections.iterators;
    exports org.apache.commons.collections.keyvalue;
    exports org.apache.commons.collections.list;
    exports org.apache.commons.collections.map;
    exports org.apache.commons.collections.set;
    exports org.apache.html.dom;
    exports org.apache.wml;
    exports org.apache.wml.dom;
    exports org.apache.xerces.dom;
    exports org.apache.xerces.dom.events;
    exports org.apache.xerces.dom3.as;
    exports org.apache.xerces.impl;
    exports org.apache.xerces.impl.dtd;
    exports org.apache.xerces.impl.dtd.models;
    exports org.apache.xerces.impl.dv;
    exports org.apache.xerces.impl.dv.dtd;
    exports org.apache.xerces.impl.dv.util;
    exports org.apache.xerces.impl.dv.xs;
    exports org.apache.xerces.impl.io;
    exports org.apache.xerces.impl.msg;
    exports org.apache.xerces.impl.validation;
    exports org.apache.xerces.impl.xpath;
    exports org.apache.xerces.impl.xpath.regex;
    exports org.apache.xerces.impl.xs;
    exports org.apache.xerces.impl.xs.identity;
    exports org.apache.xerces.impl.xs.models;
    exports org.apache.xerces.impl.xs.opti;
    exports org.apache.xerces.impl.xs.traversers;
    exports org.apache.xerces.impl.xs.util;
    exports org.apache.xerces.jaxp;
    exports org.apache.xerces.jaxp.datatype;
    exports org.apache.xerces.jaxp.validation;
    exports org.apache.xerces.parsers;
    exports org.apache.xerces.util;
    exports org.apache.xerces.xinclude;
    exports org.apache.xerces.xni;
    exports org.apache.xerces.xni.grammars;
    exports org.apache.xerces.xni.parser;
    exports org.apache.xerces.xpointer;
    exports org.apache.xerces.xs;
    exports org.apache.xerces.xs.datatypes;
    exports org.apache.xml.serialize;
    exports org.apache.xmlcommons;
    exports org.checkerframework.checker.builder.qual;
    exports org.checkerframework.checker.calledmethods.qual;
    exports org.checkerframework.checker.compilermsgs.qual;
    exports org.checkerframework.checker.fenum.qual;
    exports org.checkerframework.checker.formatter;
    exports org.checkerframework.checker.formatter.qual;
    exports org.checkerframework.checker.guieffect.qual;
    exports org.checkerframework.checker.i18n.qual;
    exports org.checkerframework.checker.i18nformatter;
    exports org.checkerframework.checker.i18nformatter.qual;
    exports org.checkerframework.checker.index.qual;
    exports org.checkerframework.checker.initialization.qual;
    exports org.checkerframework.checker.interning.qual;
    exports org.checkerframework.checker.lock.qual;
    exports org.checkerframework.checker.nullness;
    exports org.checkerframework.checker.nullness.qual;
    exports org.checkerframework.checker.optional.qual;
    exports org.checkerframework.checker.propkey.qual;
    exports org.checkerframework.checker.regex;
    exports org.checkerframework.checker.regex.qual;
    exports org.checkerframework.checker.signature.qual;
    exports org.checkerframework.checker.signedness;
    exports org.checkerframework.checker.signedness.qual;
    exports org.checkerframework.checker.tainting.qual;
    exports org.checkerframework.checker.units;
    exports org.checkerframework.checker.units.qual;
    exports org.checkerframework.common.aliasing.qual;
    exports org.checkerframework.common.initializedfields.qual;
    exports org.checkerframework.common.reflection.qual;
    exports org.checkerframework.common.returnsreceiver.qual;
    exports org.checkerframework.common.subtyping.qual;
    exports org.checkerframework.common.util.report.qual;
    exports org.checkerframework.common.value.qual;
    exports org.checkerframework.dataflow.qual;
    exports org.checkerframework.framework.qual;
    exports org.checkerframework.framework.util;
    exports org.iso_relax.verifier.jaxp.validation;
    exports org.jaxen;
    exports org.jaxen.dom;
    exports org.jaxen.dom4j;
    exports org.jaxen.expr;
    exports org.jaxen.expr.iter;
    exports org.jaxen.function;
    exports org.jaxen.function.ext;
    exports org.jaxen.function.xslt;
    exports org.jaxen.javabean;
    exports org.jaxen.jdom;
    exports org.jaxen.pattern;
    exports org.jaxen.saxpath;
    exports org.jaxen.saxpath.base;
    exports org.jaxen.saxpath.helpers;
    exports org.jaxen.util;
    exports org.jaxen.xom;
    exports org.jdom;
    exports org.jdom.adapters;
    exports org.jdom.filter;
    exports org.jdom.input;
    exports org.jdom.output;
    exports org.jdom.transform;
    exports org.jdom.xpath;
    exports org.jopendocument.dom;
    exports org.jopendocument.dom.spreadsheet;
    exports org.jopendocument.dom.style;
    exports org.jopendocument.dom.style.data;
    exports org.jopendocument.dom.template;
    exports org.jopendocument.dom.template.engine;
    exports org.jopendocument.dom.template.statements;
    exports org.jopendocument.dom.text;
    exports org.jopendocument.io;
    exports org.jopendocument.link;
    exports org.jopendocument.model;
    exports org.jopendocument.model.chart;
    exports org.jopendocument.model.draw;
    exports org.jopendocument.model.form;
    exports org.jopendocument.model.number;
    exports org.jopendocument.model.office;
    exports org.jopendocument.model.presentation;
    exports org.jopendocument.model.script;
    exports org.jopendocument.model.style;
    exports org.jopendocument.model.table;
    exports org.jopendocument.model.text;
    exports org.jopendocument.panel;
    exports org.jopendocument.print;
    exports org.jopendocument.renderer;
    exports org.jopendocument.renderer.text;
    exports org.jopendocument.sample;
    exports org.jopendocument.tools;
    exports org.jopendocument.ui;
    exports org.jopendocument.util;
    exports org.jopendocument.util.cache;
    exports org.jopendocument.util.cc;
    exports org.jopendocument.util.convertor;
    exports org.jopendocument.util.i18n;
    exports org.jopendocument.util.io;
    exports org.jopendocument.util.protocol;
    exports org.jopendocument.util.protocol.jarjar;
    exports org.mozilla.classfile;
    exports org.mozilla.javascript;
    exports org.mozilla.javascript.continuations;
    exports org.mozilla.javascript.debug;
    exports org.mozilla.javascript.jdk11;
    exports org.mozilla.javascript.jdk13;
    exports org.mozilla.javascript.jdk15;
    exports org.mozilla.javascript.optimizer;
    exports org.mozilla.javascript.regexp;
    exports org.mozilla.javascript.serialize;
    exports org.mozilla.javascript.tools;
    exports org.mozilla.javascript.tools.idswitch;
    exports org.mozilla.javascript.tools.jsc;
    exports org.mozilla.javascript.tools.shell;
    exports org.mozilla.javascript.xml;
    exports org.mozilla.javascript.xml.impl.xmlbeans;
    exports org.mozilla.javascript.xmlimpl;
    exports org.odftoolkit.odfdom;
    exports org.odftoolkit.odfdom.doc;
    exports org.odftoolkit.odfdom.doc.presentation;
    exports org.odftoolkit.odfdom.doc.table;
    exports org.odftoolkit.odfdom.dom;
    exports org.odftoolkit.odfdom.dom.attribute.anim;
    exports org.odftoolkit.odfdom.dom.attribute.chart;
    exports org.odftoolkit.odfdom.dom.attribute.config;
    exports org.odftoolkit.odfdom.dom.attribute.db;
    exports org.odftoolkit.odfdom.dom.attribute.dr3d;
    exports org.odftoolkit.odfdom.dom.attribute.draw;
    exports org.odftoolkit.odfdom.dom.attribute.fo;
    exports org.odftoolkit.odfdom.dom.attribute.form;
    exports org.odftoolkit.odfdom.dom.attribute.grddl;
    exports org.odftoolkit.odfdom.dom.attribute.meta;
    exports org.odftoolkit.odfdom.dom.attribute.number;
    exports org.odftoolkit.odfdom.dom.attribute.office;
    exports org.odftoolkit.odfdom.dom.attribute.presentation;
    exports org.odftoolkit.odfdom.dom.attribute.script;
    exports org.odftoolkit.odfdom.dom.attribute.smil;
    exports org.odftoolkit.odfdom.dom.attribute.style;
    exports org.odftoolkit.odfdom.dom.attribute.svg;
    exports org.odftoolkit.odfdom.dom.attribute.table;
    exports org.odftoolkit.odfdom.dom.attribute.text;
    exports org.odftoolkit.odfdom.dom.attribute.xforms;
    exports org.odftoolkit.odfdom.dom.attribute.xhtml;
    exports org.odftoolkit.odfdom.dom.attribute.xlink;
    exports org.odftoolkit.odfdom.dom.attribute.xml;
    exports org.odftoolkit.odfdom.dom.element;
    exports org.odftoolkit.odfdom.dom.element.anim;
    exports org.odftoolkit.odfdom.dom.element.chart;
    exports org.odftoolkit.odfdom.dom.element.config;
    exports org.odftoolkit.odfdom.dom.element.db;
    exports org.odftoolkit.odfdom.dom.element.dc;
    exports org.odftoolkit.odfdom.dom.element.dr3d;
    exports org.odftoolkit.odfdom.dom.element.draw;
    exports org.odftoolkit.odfdom.dom.element.form;
    exports org.odftoolkit.odfdom.dom.element.math;
    exports org.odftoolkit.odfdom.dom.element.meta;
    exports org.odftoolkit.odfdom.dom.element.number;
    exports org.odftoolkit.odfdom.dom.element.office;
    exports org.odftoolkit.odfdom.dom.element.presentation;
    exports org.odftoolkit.odfdom.dom.element.script;
    exports org.odftoolkit.odfdom.dom.element.style;
    exports org.odftoolkit.odfdom.dom.element.svg;
    exports org.odftoolkit.odfdom.dom.element.table;
    exports org.odftoolkit.odfdom.dom.element.text;
    exports org.odftoolkit.odfdom.dom.element.xforms;
    exports org.odftoolkit.odfdom.dom.style;
    exports org.odftoolkit.odfdom.dom.style.props;
    exports org.odftoolkit.odfdom.incubator.doc.draw;
    exports org.odftoolkit.odfdom.incubator.doc.number;
    exports org.odftoolkit.odfdom.incubator.doc.office;
    exports org.odftoolkit.odfdom.incubator.doc.style;
    exports org.odftoolkit.odfdom.incubator.doc.text;
    exports org.odftoolkit.odfdom.incubator.meta;
    exports org.odftoolkit.odfdom.incubator.search;
    exports org.odftoolkit.odfdom.pkg;
    exports org.odftoolkit.odfdom.pkg.manifest;
    exports org.odftoolkit.odfdom.type;
    exports org.w3c.dom;
    exports org.w3c.dom.bootstrap;
    exports org.w3c.dom.css;
    exports org.w3c.dom.events;
    exports org.w3c.dom.html;
    exports org.w3c.dom.ls;
    exports org.w3c.dom.ranges;
    exports org.w3c.dom.stylesheets;
    exports org.w3c.dom.traversal;
    exports org.w3c.dom.views;
    exports org.w3c.dom.xpath;
    exports org.xml.sax;
    exports org.xml.sax.ext;
    exports org.xml.sax.helpers;
    requires java.logging;
    requires java.scripting;
    requires java.sql;
    requires java.desktop;
    requires java.compiler;
    requires java.sql.rowset;
    requires jdk.unsupported;
    provides javax.xml.parsers.DocumentBuilderFactory with org.apache.xerces.jaxp.DocumentBuilderFactoryImpl;
    provides javax.script.ScriptEngineFactory with com.sun.script.ognl.OgnlScriptEngineFactory;
    provides javax.xml.datatype.DatatypeFactory with org.apache.xerces.jaxp.datatype.DatatypeFactoryImpl;
    provides javax.xml.validation.SchemaFactory with org.apache.xerces.jaxp.validation.XMLSchemaFactory,
                org.iso_relax.verifier.jaxp.validation.RELAXNGSchemaFactoryImpl;
    provides org.w3c.dom.DOMImplementationSourceList with org.apache.xerces.dom.DOMXSImplementationSourceImpl;
    provides org.xml.sax.driver with org.apache.xerces.parsers.SAXParser;
    provides javax.xml.parsers.SAXParserFactory with org.apache.xerces.jaxp.SAXParserFactoryImpl;
}

Error:

C:\Users\Leheess\Desktop\miq-converter\app\build\jlinkbase\tmpjars\miq.converter.merged.module\module-info.java:291: error: cannot find symbol
    provides org.w3c.dom.DOMImplementationSourceList with org.apache.xerces.dom.DOMXSImplementationSourceImpl;
                        ^
  symbol:   class DOMImplementationSourceList
  location: package org.w3c.dom
C:\Users\Leheess\Desktop\miq-converter\app\build\jlinkbase\tmpjars\miq.converter.merged.module\module-info.java:292: error: cannot find symbol
    provides org.xml.sax.driver with org.apache.xerces.parsers.SAXParser;
                        ^
  symbol:   class driver
  location: package org.xml.sax
2 errors

Execution failed for task ':app:createMergedModule'.
> Process 'command 'C:\Users\Leheess\.jdks\openjdk-18/bin/javac'' finished with non-zero exit value 1

`package java.lang.module does not exist` leads me to believe it is using a JDK older than 9 to compile. — VGR, Mar 31 '22 at 23:00
@VGR, I checked my JAVA_HOME but it points to openjdk 18 - where does jlink get it's jdk from? — leonheess, Mar 31 '22 at 23:10
It appears that the program failed to compile, so jlink was never invoked. The build simply didn’t get that far. — VGR, Mar 31 '22 at 23:12
@VGR You were right! Jlink couldn't find any JDK and after I specified which one to use it worked. So thank you very much! However, now I get `error: cannot find symbol provides org.w3c.dom.DOMImplementationSourceList with org.apache.xerces.dom.DOMXSImplementationSourceImpl;` which is weird because compiling locally and the jar task work fine - any ideas by chance? — leonheess, Apr 01 '22 at 14:07
Are you sure you’re using Java 9 or later to compile? That message suggests a Java 8 or older compiler, which doesn’t understand what module-info.java is. — VGR, Apr 01 '22 at 14:28
@VGR The previous error from my question has been resolved. I am using openjdk-18. The new error is: `error: cannot find symbol provides org.w3c.dom.DOMImplementationSourceList with org.apache.xerces.dom.DOMXSImplementationSourceImpl;` — leonheess, Apr 01 '22 at 14:34
Yes, and that’s what I’m referring to. It appears the compiler does not recognize that `provides` is a valid identifier. You may want to edit your question and include your entire module-info.java, so we can see if it has syntax errors. I’m also wondering if somehow you have non-breaking spaces in it. — VGR, Apr 01 '22 at 14:38
I’m not sure how those got into your module-info.java, but it appears they are both invalid. There is no interface or class named DOMImplementationSourceList in the [org.w3c.dom package](https://docs.oracle.com/en/java/javase/18/docs/api/java.xml/org/w3c/dom/package-summary.html). `org.xml.sax.driver` [does not appear to be a valid service provider interface](https://docs.oracle.com/en/java/javase/18/docs/api/java.xml/module-summary.html#services-summary) and it doesn’t even look like a class name. You don’t even need those; Java SE already implements all of SAX and DOM. — VGR, Apr 01 '22 at 20:17
@VGR Whenever I run the jlink task they get added to the file - how can I prevent that? — leonheess, Apr 01 '22 at 23:50
@VGR I can pay you to debug this with me - would that be an option? — leonheess, Apr 03 '22 at 04:02
Try removing this line: `implementation 'xerces:xercesImpl:2.12.2'` You shouldn’t need it, since Java SE comes with XML parser implementations. — VGR, Apr 04 '22 at 01:00
@VGR Same error, I updated the question as well to stay consistent. Locally the app still runs so it seems like the line actually was superfluous. — leonheess, Apr 04 '22 at 07:30
After removing that line from your build file, did you remove the problematic lines from module-info.java? — VGR, Apr 04 '22 at 12:39
@VGR Yes, I did. I even tried deleting the entire file but it was re-generated identically. — leonheess, Apr 04 '22 at 12:50
*"I read that this is no longer the preferred way of distributing"* If you know that your users have a JRE installed on their machines, then distributing a jar is perfectly fine. — Olivier, Apr 05 '22 at 07:31
*"so I added gradle to my project and tried building with jlink"* You don't need Gradle to use jlink. It's just a command-line tool (like javac). You should learn about jlink and use it directly on the command-line. — Olivier, Apr 05 '22 at 07:35
@Olivier Is it wrong to use gradle here? How would I manage dependencies? — leonheess, Apr 05 '22 at 12:31
I have never used gradle but you can use Maven to handle dependencies. However I ran into a lot of issues using jlink. I made a video series on how and what to use to create a runnable jar, and even how to convert into an .exe file and even a step further, making an installer that will make sure your program deploys and uses the right JRE on your clients machine. Please pardon the quality and the fact I am using javaFx https://www.youtube.com/watch?v=IoPXzopsmpE&t=607s — ADSquared, Apr 09 '22 at 15:33

score 2 · Accepted Answer · answered Apr 05 '22 at 21:20

Add the following to your jlink block to get past those two errors (cf. mergedModule docs):

    mergedModule {
        // Don't use any of the suggested module info.
    }

When I tried this with your build.gradle file, I had to also add the following to the jlink block later:

    jarExclude('jOpenDocument', 'JDOMAbout*')

I also added a src/main/java/module-info.java file; example:

module com.example.miq {
    exports miq.converter;
}

Finally, I extended the application block of your build.gradle file with the following:

    // Use the same module name as in your src/main/java/module-info.java file.
    mainModule = 'com.example.miq'

These changes got the jlink task working for me with your build configuration.

How to build a Java app with gradle and jlink?

1 Answers1