Develop Reference

JavaFX with Gradle error module not found

I'm creating a sample demo application with JavaFX in IntelliJ, but I need to use a library called the JavaFaker library. I'm using Gradle as the build system, but every time I try to add the library, either as the implementation in the build.gradle file, or via IntelliJ project structure options, the module.java file says error: module not found. I've already tried adding it to modules but nothing changes.
module-info.java
module com.example.demo1 {
requires javafx.controls;
requires javafx.fxml;
requires javafaker;
opens com.example.demo1 to javafx.fxml;
exports com.example.demo1;
}
build.gradle
plugins {
id 'java'
id 'application'
id 'org.openjfx.javafxplugin' version '0.0.10'
id 'org.beryx.jlink' version '2.24.1'
}
group 'com.example'
version '1.0-SNAPSHOT'
repositories {
mavenCentral()
}
ext {
junitVersion = '5.8.2'
javaFakerVersion = '1.0.2'
}
sourceCompatibility = '17'
targetCompatibility = '17'
tasks.withType(JavaCompile) {
options.encoding = 'UTF-8'
}
application {
mainModule = 'com.example.demo1'
mainClass = 'com.example.demo1.HelloApplication'
}
javafx {
version = '17.0.1'
modules = ['javafx.controls', 'javafx.fxml']
}
dependencies {
implementation("com.github.javafaker:javafaker:${javaFakerVersion}")
testImplementation("org.junit.jupiter:junit-jupiter-api:${junitVersion}")
testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:${junitVersion}")
}
test {
useJUnitPlatform()
}
jlink {
imageZip = project.file("${buildDir}/distributions/app-${javafx.platform.classifier}.zip") as RegularFile
options = ['--strip-debug', '--compress', '2', '--no-header-files', '--no-man-pages']
launcher {
name = 'app'
}
}
jlinkZip {
group = 'distribution'
}
error message
> Task :HelloApplication.main() FAILED
Error occurred during initialization of boot layer
java.lang.module.FindException: Module javafaker not found, required by com.example.demo1

I tried for a while to get this to work with Gradle but was unable to. I don't know Gradle well, but unless you do, I don't advise trying it.
Alternate option: use a static import
I didn't try this, but this is suggested in another answer.
Before you try this, see:
What's the difference between requires and requires static in module declaration
It is IMO, a bit of a hack in this usage case. This makes the module optional at runtime. But, if the module is on the classpath instead of the module path its code can still be used. More information quoted from the linked answer:
A requires static clause expresses a dependency that is optional at
run time. That means at compile time the module system behaves exactly
as described above.
At run time, on the other hand, it mostly ignores requires static
clauses. If it encounters one, it does not resolve it. That means, if
an observable module is only referenced with requires static, it does
not make it into the module graph!
Alternate option: Non-modular project
You can fix this issue by making your project non-modular:
Delete your module-info.java file.
Run your application with JavaFX modules on the module-path.
The org.openjfx.javafxplugin you are already doing will help achieve this by specifying the modules to be used.
To execute the application directly in the IDE rather than through Gradle, you will need to specify the module options to the VM for the IDE execution configuration (information on that is in the getting started documentation at openjfx.io).
For packaging, switch to using the badass-runtime-plugin rather than the badass-jlink-plugin. This will package the application via jpackage rather than jlink (which cannot package non-modular applications or applications with automatic modules).
In the application block of your build file, you no longer need to specify the module for your application as you no longer have one.
While that means that your application is no longer modular, in this case, in my opinion, this is not such a big loss. The dependencies you are using are not well-defined modules, so you can't use jlink to create a package for your application, and you don't have the level of modular encapsulation and definition you would normally receive for fully modular projects.
For more information, see the Getting started instructions at:
https://openjfx.io/openjfx-docs/
Under the sections "Non-Modular with Gradle" for your selected IDE.
Alternate option: Using Maven
It is easy to get this to work with Maven.
Create a new JavaFX project
Choose Maven as your build system instead of Gradle.
Add the javafaker dependency to your pom.xml.
<dependency>
<groupId>com.github.javafaker</groupId>
<artifactId>javafaker</artifactId>
<version>1.0.2</version>
</dependency>
Press the refresh icon in the Maven window to reimport the Maven project into the IDE.
Add the requires clause for the javafaker module into your module-info.java
requires javafaker;
Add the code to use javafaker to your app.
I don't have code to use javafaker, so I could not verify that the last step would work, but, give it a try . . .
Why you can receive this issue when using Gradle, but not Maven
Looking at the Gradle Documentation section "Using libraries that are not modules":
A third case are traditional libraries that provide no module information at all — for example commons-cli:commons-cli:1.4. Gradle puts such libraries on the classpath instead of the module path. The classpath is then treated as one module (the so called unnamed module) by Java.
This is the case with the javafaker dependency that you are using. It has no module-info.java and does not define the property Automatic-Module-Name in its manifest file (which are the other two cases in the section). Both the other cases result in Gradle putting the library on the module path, but the case you have means that it is on the class path.
This is a problem when you want to access the code from a named module that you define, which you have because you created a module-info.java.
Your module can only find code and resources of modules it requires (which need to be on the module path), so you add requires javafaker to the module-info.java, and get the following when you try to run through the IDE:
java.lang.module.FindException: Module javafaker not found, required by com.example.demo1
So you remove the requires javafaker from the module-info.java as advised by the Gradle documentation I linked and you get the following when you try to compile:
Package 'com.github.javafaker' is declared in module 'javafaker', but module 'com.example.demo1' does not read it
So you must place the library in the module-info to use it, but you can't place the library in module-info because Gradle puts in on the classpath -> catch-22.
There are workarounds to this such as providing VM arguments to allow access to the unnamed module (which is the classpath), or maybe modifying the module path handling of the Gradle build and/or IDE somehow (I don't know how), but they are pretty ugly.
On the other hand, for this case, Maven acts differently from Gradle, it places the dependent library on the module path, even if it does not have a module-info.java or Automatic-Module-Name defined. This means that it was (for me) much easier to set up and use.
Incidental advice on module naming
This is not an error, but note: Although module names with numbers in them are now allowed due to a change in the module system specification, it is probably best not to put numbers in module names to prevent the module name and version info being confused.

I've had a similar issue recently. Adding static to the requires statement helped however. Maybe this will fix your issue without having to switch to maven.
So you'd need to add: requires static javafaker;

How to add com.fasterxml.jackson.core.exc.InputCoercionException as a dependency in gradle?

I am getting java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/PropertyNamingStrategies which is used in another project. I have included jackson jar in current gradle project as well. But while starting the project I am getting the above mentioned error. Seems like we need to add com.fasterxml.jackson.core.exc.InputCoercionException as an dependency but I am not able to understand where to add this as a dependency ? Can someone please help ?

java.lang.NoClassDefFoundError Either means - missing dependency with class com/fasterxml/jackson/databind/PropertyNamingStrategies or class was removed meaning jackson libs versions used in your project dependencies won't work together.
How to start solving problems like those.
1, Via IDE try to find missing class if is present. If is not present then try to find jar with missing class on internet and add as dependency. In case your IDE show class is present then problem may be with import scope. Scope management differ per used technology so provide detail which one you use or paste dependencies from build.kts . Make sure you use implementation in case you import this class in project and not runtimeOnly.
2, You found class then try to print project dependency tree command differ per used technology. For gradle ./gradlew dependencies or for submodule ./gradlew submoduleName:dependencies and look at versions of jackson in your project.
3, Check jackson lib with version listed via dependency tree contains missing class.
How to avoid problem like those with spring boot.
I would recoment to use BOM provided by spring boot project, versions in there should work together.
For gradle with kotlin DSL we import it like this
import org.springframework.boot.gradle.plugin.SpringBootPlugin
plugins {
id("org.springframework.boot") version "2.6.2"
}
dependencies {
val springBootPlatform = platform(SpringBootPlugin.BOM_COORDINATES)
annotationProcessor(springBootPlatform)
implementation(springBootPlatform)
//this version has to be searched for spring boot version
implementation(platform("org.springframework.cloud:spring-cloud-dependencies:2021.0.0"))
//put desired jackson dependencies
implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
}

Getting NoClassDefFoundError -> com/sun/jna/platform/win32/Psapi with Eclipse

My program relies on the following code to get available system memory:
import oshi.SystemInfo;
import oshi.hardware.HardwareAbstractionLayer;
SystemInfo si = new SystemInfo();
HardwareAbstractionLayer hal = si.getHardware();
// Next line throws exception: NoClassDefFoundError -> com/sun/jna/platform/win32/Psapi
long availableBytes = hal.getMemory().getAvailable();
double availableMegabytes = ((double) availableBytes) / 1048576;
double availableGigabytes = ((double) availableMegabytes)/1024;
Update: After deleting every occurrence of oshi-core from every project in Workspace (to remove possibility of transient conflict dependency - only 4.2.1 is left). Now the error I get is -> java.lang.NoClassDefFoundError: com/sun/jna/platform/win32/VersionHelpers
In pom.xml I've added oshi-core dependency - I've tried almost every version starting from version 3.4.0 to latest version 4.2.1 and they all result in the same error.
I realize oshi-core relies on jna and jna-platform. In Dependency Hierarchy I see both have resolved (compiled) to version 5.5.0.
What is causing this error and how can it be solved?
Thanks!
P.S
I've seen some other threads with similar error but could not find any thread with this exact problem (missing com/sun/jna/platform/win32/Psapi)

While you've pointed out in your comments that you think the latest version of JNA is being resolved, the errors indicate that your project does not have the most recent version of jna-platform (or possibly it has multiple versions linked on the classpath). This is nearly always the case for NoClassDefFoundError and while you're troubleshooting in the right direction, evidence indicates there's an old jna-platform version in your project somewhere.
The com.sun.jna.platform.win32.VersionHelpers class is in jna-platform version 5.3.0 and newer. The GetPerformanceInfo() method required for the method call giving you the error is in the com.sun.jna.platform.win32.Psapi class is in jna-platform version 4.3.0 and newer. If your classloader can't find these classes, then you don't have the correct jars linked to your project -- or you have incorrect jars linked alongside the correct ones.
Maven resolves dependencies by level... first it does all the dependencies you list in your POM (in order), then the transitive dependencies of those projects (in order) and so on. Ensuring the most recent version of JNA is used can be enforced by either (or both) of:
Specify oshi-core dependency earlier in your list of dependencies
in your POM, specifically, before any project that depends on an
earlier version of JNA.
Explicitly specify the jna and
jna-platform versions (5.5.0) in your top-level POM.
Also, in Eclipse, be sure to go through the menus to Update Maven Project to ensure your dependencies are in sync after changes in the POM.
It's possible that your local repository is not downloading the updated jar, in which case you can purge it (or just delete any JNA artifacts, or everything, from C:\Users\<username>\.m2\repository and let it rebuild.)
Also check the classpath in Eclipse. If you have manually added dependencies (e.g., to JNA) before setting up your POM to get them from Maven, you could be using those.
If the above hints do not resolve your problem, please post the contents of the dependencies section your pom.xml file so we can provide additional advice.

Seems oshi-core relies on internal undocumented features of the Sun / Oracle JVM, and you're running on a different and/or newer JVM that doesn't have that undocumented feature anymore. That's the risk of using undocumented features.
Get a newer/other version of oshi-core that supports the version of the JVM you're using, or switch to use a JVM that oshi-core supports.

Android/Gradle: how to find the good mix of Google dependencies versions?

I have often compiling errors due to the versions of the different Google dependencies that have bad interactions between them.
Typical gradle file:
implementation 'com.google.android.gms:play-services-analytics:16.0.1'
implementation 'com.google.android.gms:play-services-ads:17.1.1'
implementation 'com.google.firebase:firebase-core:16.0.1'
implementation 'com.google.firebase:firebase-messaging:17.1.0'
implementation 'com.google.ads.mediation:facebook:4.22.1.0'
At the end, the project doesn't compile with an error like this:
FAILURE: Build failed with an exception.
* What went wrong:
Could not determine the dependencies of task ':XXX:preDebugBuild'.
> In project 'XXX' a resolved Google Play services library dependency depends on another at an exact version (e.g. "[1
5.0.1]", but isn't being resolved to that version. Behavior exhibited by the library will be unknown.
Dependency failing: com.google.android.gms:play-services-tasks:15.0.1 -> com.google.android.gms:play-services-basement#[
15.0.1], but play-services-basement version was 16.0.1.
The following dependencies are project dependencies that are direct or have transitive dependencies that lead to the art
ifact with the issue.
-- Project 'XXX' depends onto com.google.firebase:firebase-config#16.0.0
-- Project 'XXX' depends onto com.google.android.gms:play-services-analytics#16.0.1
-- Project 'XXX' depends onto com.facebook.android:audience-network-sdk#4.22.1
-- Project 'XXX' depends onto com.google.android.gms:play-services-ads#17.1.1
-- Project 'XXX' depends onto com.google.firebase:firebase-core#16.0.1
-- Project 'XXX' depends onto com.google.firebase:firebase-messaging#17.1.0
For extended debugging info execute Gradle from the command line with ./gradlew --info :XXX:assembleDebug to see the
dependency paths to the artifact. This error message came from the google-services Gradle plugin, report issues at http
s://github.com/google/play-services-plugins and disable by adding "googleServices { disableVersionCheck = false }" to yo
ur build.gradle file.
* Try:
Run with --stacktrace option to get the stack trace. Run with --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 25s
How to solve this kind of issue with a reliable methodology ? (with the goal to have the latest possible version for each lib)

According to your Log file
Dependency failing: com.google.android.gms:play-services-tasks:15.0.1 -> com.google.android.gms:play-services-basement#[
15.0.1], but play-services-basement version was 16.0.1.
Its problem occurred due to different version of Google Play Service.
To resolve these kind of problems in android define a constant version in gradle.properties file
# Project-wide Gradle settings.
# IDE (e.g. Android Studio) users:
# Gradle settings configured through the IDE *will override*
# any settings specified in this file.
# For more details on how to configure your build environment visit
# http://www.gradle.org/docs/current/userguide/build_environment.html
# Specifies the JVM arguments used for the daemon process.
# The setting is particularly useful for tweaking memory settings.
org.gradle.jvmargs=-Xmx1536m
# When configured, Gradle will run in incubating parallel mode.
# This option should only be used with decoupled projects. More details, visit
# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
org.gradle.parallel=true
COMPILE_SDK_VERSION=26
BUILD_TOOLS_VERSION=27.0.3
TARGET_SDK_VERSION=26
MIN_SDK_VERSION=17
ANDROID_SUPPORT_VERSION=26.1.0
PLAY_SERVICE_VERSION=16.0.1
To use these constant in build.gradle(Module:app) define like below:
dependencies {
implementation fileTree(include: ['*.jar'], dir: 'libs')
implementation "com.android.support:appcompat-v7:${ANDROID_SUPPORT_VERSION as String}"
implementation "com.google.android.gms:play-services-analytics:${PLAY_SERVICE_VERSION as String}"
implementation "com.google.android.gms:play-services-ads:${PLAY_SERVICE_VERSION as String}"
}
Similarly you can define others library like firebase or others.

I don't think there is a straight answer to your question.
My recommendation would be to use com.google.firebase:firebase-ads:17.1.0 since it should also include both play-services-analytics and play-services-ads which can then be removed. And then keeping an eye on the release versions of your libraries every two weeks.
Yes, I know, this is probably not the answer you were looking for, but on the long run, it will give you less headaches.
If that's not enough to convince you, there is another way of reducing the amount of time it takes to keep the versions up to date using + in the minor version number (for instance 16.0.+ instead of 16.0.0).
WARNING: Automatically increasing the version numbers could lead to issues (i.e.: different versions resolved in your CI and your local machine, unexpected incompatibilities, irreproducible builds, etc.)
On your main build.gradle file define a constant:
allprojects {
ext {
global_version_firebase = '16.0.+'
}
}
And use it like implementation "com.google.firebase:firebase-core:$global_version_firebase"
And some version differences on firebase and play services are actually major changes (i.e.: firebase-core:16.0.4 and firebase-ads:17.1.0), so the convenient + on the minor version would not work for all cases, and you would need to put the + on the whole version number, which is a no-go.

Why does Gradle resolve a package with wrong version number?

I am building a web application and I am using Dropwizard 1.3.0, which has a dependency on jetty-io 9.4.8. This dependency has conflicts with another package (dropwizard-websocket-jee7-bundle 2.0.0), because it seem to fetch the wrong version number.
I looked into tha package, and found the method that has been renamed in 9.4.x - AbstractWebSocketConnection.java from 9.3.x - AbstractWebSocketConnection.java. The issue is that even though in Gradle the dependency tree shows I fetched 9.4.8 (the new one which I need), I still get the older, 9.3.x java file which causes the conflicts. I tried to Invalidate Caches / Restart and rebuild the whole project, but I seem to get the outdated file all the time.
What are the possible solutions for this?

If your bad class are imported by a transitive dependency, try to exclude explicit the transitive dependency.
For example if your required library is 'my.group:requiredLibrary:2.0.0' and there are another version in 'my.group:someDependency:0.1.5' you can do like this:
dependencies{
compile 'my.group:requiredLibrary:2.0.0'
compile ('my.group:someDependency:0.1.5'){
exclude group: 'my.group' module:'requiredLibrary'
}
}

Try forcing a particular version in your build.gradle
Example here: https://docs.gradle.org/current/dsl/org.gradle.api.artifacts.ResolutionStrategy.html