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Using Eclipse NonNull annotations with multiple Gradle projects

We've been using the Eclipse #NonNull and #Nullable annotations in our code for a while.
We are now adding some Spring projects defined with Gradle to our system. These projects will share quite a bit of code with our standalone projects as well.
We are seeing a problem due the Eclipse annotations (being compile time checking) don't work when a Spring/Gradle project refers to the shared code via Gradle generated .jar file. Eclipse needs to have the source of the shared jar in order for the annotations to work. Attaching the source in the Eclipse project only works until you need to do a Gradle Refresh, as that rebuilds the eclipse .project and .classpath files.
It's also a problem that you have to explicitly rebuild the shared .jar each time you make a change to the shared code. It's not done automatically.
I haven't found a way to have the Spring/Gradle projects just use a 2nd source directory for the shared code, and not need to have the shared code as a generated .jar file.
Is there any good way to have shared code between multiple Gradle projects in Eclipse - without using an intermediate .jar file? (Or some other way to get the Eclipse annotations to work.)
Not really sure how to give a full example, as most of this is gradle and eclipse configuration.
Here are the Gradle config files: settings.gradle
pluginManagement {
repositories {
maven { url 'https://repo.spring.io/milestone' }
gradlePluginPortal()
}
}
rootProject.name = 'App1-Account-Manager'
and build.gradle
plugins {
id 'org.springframework.boot' version '2.5.0-RC1'
id 'io.spring.dependency-management' version '1.0.11.RELEASE'
id 'java'
}
group = 'com.efi'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'
repositories {
mavenCentral()
maven { url 'https://repo.spring.io/milestone' }
}
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
implementation 'org.springframework.boot:spring-boot-starter-security'
implementation 'org.springframework.boot:spring-boot-starter-web'
implementation group: 'io.jsonwebtoken', name: 'jjwt', version: '0.2'
implementation 'org.springframework.boot:spring-boot-starter-amqp'
testImplementation 'org.springframework.boot:spring-boot-starter-test'
testImplementation 'org.springframework.amqp:spring-rabbit-test'
implementation files('lib/eflow/eFlowClientApi.jar',
'lib/eflow/eFlowCryptography.jar',
'lib/eflow/json-simple-1.1.1.jar',
'lib/eflow/commons-codec-1.4.jar',
'lib/eflow/commons-io-2.6.jar',
'lib/eflow/commons-lang-2.6.jar',
'lib/eflow/commons-logging-1.2.jar',
'../App1-Commons/build/libs/App1-Commons-0.0.1-SNAPSHOT.jar'
)
implementation group: 'org.eclipse.jdt', name: 'org.eclipse.jdt.annotation', version: '2.1.100'
implementation group: 'com.google.code.gson', name: 'gson', version: '2.8.7'
runtimeOnly 'org.postgresql:postgresql'
testImplementation 'org.springframework.security:spring-security-test'
}
test {
useJUnitPlatform()
}
App1-Commons is the project of shared code that multiple other projects depend on. That's where a bunch of the #NonNull annotations are.
I can set the App1-Account-Manager project to depend on the App1-Commons project in eclipse - but as soon as you run a Gradle Refresh, it looses that connection.
I'd prefer to just have the source from App1-Commons included in the App1-Account-Manager project - but I don't see how to configure Gradle to do that with Eclipse projects.

I think I found the solution. I need to add a SourceSets block to the build.gradle file like this:
sourceSets {
main {
java {
srcDir 'src/main/java'
srcDir '../App1-Commons/src/main/java'
}
}
}
And remove the reference to the App1-Commons jar file.

How to use gradle 'api' dependency

I tried using the 'api' dependency keyword in my project , but I got this error saying it cannot find method api()
I tried it on a new project. this is the build.gradle file:
plugins {
id 'java'
}
group 'com.test'
version '1.0-SNAPSHOT'
sourceCompatibility = 1.8
repositories {
mavenCentral()
}
dependencies {
testCompile group: 'junit', name: 'junit', version: '4.12'
api group: 'com.google.guava', name: 'guava', version: '27.0.1-jre'
}
I am using gradle V4.9.
when I run gradle build I get this:
Could not find method api() for arguments [{group=com.google.guava, name=guava, version=27.0.1-jre}] on object of type org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler
If I replace 'api' with 'implementation' everything works fine
What am I missing here?
Is there any setting that needs to be done?

The api configuration comes from the java-library plugin, in your build script you have just applied java plugin. See https://docs.gradle.org/current/userguide/java_library_plugin.html
The key difference between the standard Java plugin and the Java Library plugin is that the latter introduces the concept of an API exposed to consumers. A library is a Java component meant to be consumed by other components. It’s a very common use case in multi-project builds, but also as soon as you have external dependencies.
Just apply the java-library plugin (which extends java plugin) and it should work:
plugins {
id 'java-library'
}

For those using kotlin build scripts use the following:
plugins {
id("org.gradle.kotlin.kotlin-dsl")
}

java 10 gradle project : automatic module not found

I created a java 10 project with intelliJ, using gradle.
I copied some stuff into it (some "AppFx" class using the library guava and javaFx, and a personal build.gradle file).
I also added a module-info.java file in src/main/java with this content:
module biblio5.main {
requires javafx.graphics;
requires javafx.controls;
requires javafx.base;
requires guava;
}
in which grava is an automatic module.
here is the relevant part of build.gradle:
dependencies {
testCompile group: 'junit', name: 'junit', version: '4.12'
compile 'com.google.guava:guava:23.0'
}
intelliJ can compile the project (using the hammer-like icon) but when I run the compileJava gradle task from intelliJ, I get an error:
13:12:46: Executing task 'compileJava'...
Task :compileJava FAILED C:\Users\lolve\Documents\gradle_java\biblio5\src\main\java\module-info.java:5:
error: module not found: guava
requires guava;
^ 1 error
I spent a lot of time on the net but did not manage to find an answer.
thank you
ps: here is the entire build.gradle:
buildscript {
dependencies {
classpath group: 'de.dynamicfiles.projects.gradle.plugins', name: 'javafx-gradle-plugin', version: '8.8.2'
classpath 'eu.appsatori:gradle-fatjar-plugin:0.3'
}
repositories {
maven {url "https://mvnrepository.com/artifact/de.dynamicfiles.projects.gradle.plugins/javafx-gradle-plugin"}
mavenCentral()
maven { url "https://oss.sonatype.org/content/repositories/snapshots" }
jcenter()
}
}
plugins {
id 'java'
id 'application'
id 'edu.sc.seis.launch4j' version '2.4.4'
}
apply plugin: 'javafx-gradle-plugin'
apply plugin: 'eu.appsatori.fatjar'
group 'lorry'
version '1'
sourceCompatibility = 1.10
repositories {
// Use jcenter for resolving your dependencies.
// You can declare any Maven/Ivy/file repository here.
maven {url "https://mvnrepository.com/artifact/de.dynamicfiles.projects.gradle.plugins/javafx-gradle-plugin"}
jcenter()
mavenCentral()
maven { url "https://oss.sonatype.org/content/repositories/snapshots" }
}
dependencies {
testCompile group: 'junit', name: 'junit', version: '4.12'
compile 'com.google.guava:guava:23.0'
}
//********************************************************************************************
launch4j {
outfile='bibliotek-v3.exe'
mainClassName = 'lorry.AppFx'
icon = "${projectDir}\\icons\\hands2.ico"
copyConfigurable = project.tasks.fatJar.outputs.files
//jar = "lib/${project.tasks.fatJar.archiveName}"
//headerType = "console"
jar = "${buildDir}\\productFatJar\\fat.jar"
}
jar {
baseName = 'executable3'
version = ''
manifest {
attributes(
'Class-Path': configurations.compile.collect { it.getName() }.join(' '),
'Main-Class': 'lorry.AppFx'
)
}
}
task copyExecutable(type: Copy) {
from file("${buildDir}\\launch4j\\bibliotek-v3.exe")
into file("c:\\Users\\lolve\\Documents\\gradle_java\\produits")
}
task copyJar(type: Copy) {
from file("${buildDir}\\jfx\\app\\bibliotek-v3.jar")
into file("c:\\Users\\lolve\\Documents\\gradle_java\\produits")
}
task copyFatJar(type: Copy) {
from file("${buildDir}\\productFatJar\\fat.jar")
into file("c:\\Users\\lolve\\Documents\\gradle_java\\produits")
}
createExe.doLast{
tasks.copyExecutable.execute()
}
task createJar(){
doLast{
tasks.jfxJar.execute()
tasks.jfxNative.execute()
tasks.copyJar.execute()
}
}
jfx {
jfxMainAppJarName = "bibliotek-v3.jar"
// minimal requirement for jfxJar-task
mainClass = 'lorry.AppFx'
// minimal requirement for jfxNative-task
vendor = 'lolveley'
}
fatJar {
destinationDir=file("${buildDir}\\productFatJar")
archiveName="fat.jar"
manifest {
attributes(
'Class-Path': configurations.compile.collect { it.getName() }.join(' '),
'Main-Class': 'lorry.AppFx'
)
}
}
task createFats(){
doLast{
tasks.fatJar.execute()
tasks.copyFatJar.execute()
tasks.createExe.execute()
}
}
EDIT
well, I made the change, and now I have "com.google.commons" instead guava in module-info.java, but I still get this error:
Testing started at 14:20 ... 14:20:14: Executing task 'check'...
Task :compileJava FAILED C:\Users\lolve\Documents\gradle_java\biblio5\src\main\java\module-info.java:5:
error: module not found: com.google.common
requires com.google.common;
^ 1 error
I changed gradle in intelliJ (the default option - recommended - was "default gradle wrapper") to my local gradle (v4.9), but without any effect.
What do you mean by "compatible with java"? What about try with a java 9 installation?

Update: Gradle 6.4 added basic support for Jigsaw modules. See this sample in the documentation (which also links to other related documentation). Note that the Building Java 9 Modules article linked to in this answer has changed significantly since this answer was posted.
The issue is Gradle still (as of 4.10-rc-2) doesn't have first-class support for Jigsaw modules. All the tasks will use the classpath, not the modulepath, when executing. This obviously will cause issues when trying to create a modular library/application (with module-info.java).
If you want to use Jigsaw modules in your project you should read Building Java 9 Modules. Your scenario, as #nullpointer mentions, is best covered by this section of the linked document. The takeaway is to add the following to your build.gradle file:
ext.moduleName = 'your.module'
compileJava {
inputs.property('moduleName', moduleName)
doFirst {
options.compilerArgs = [
'--module-path', classpath.asPath
]
classpath = files()
}
}
They also have sections for modifying the compileTestJava task (here) and the test task (here). Personally, I tend to not modify those tasks as testing often requires a lot of reflection which in turn requires a lot of --add-opens arguments. If you find out that's not true (haven't tried it in a while) or there's a better way, please let me know.
If your Gradle project is an application you also want to read the section covering the run and assemble tasks.
There is an experimental Gradle plugin that does all this for you: experimental-jigsaw. The plugin is limited, however, and there is a fork on GitHub, named chainsaw, that adds more features. Note: I don't know how maintained either plugin is.
Another Gradle plugin is available: Gradle Modules Plugin.
If you want to watch for updates regarding Jigsaw support in Gradle they maintain an epic on GitHub.
Also, to include what #nullpointer commented, you should be using a version of Guava that includes an Automatic-Module-Name entry in its manifest. Without this entry (combined with no module-info) the name of the module is subject to the name of the jar file; which may change unexpectedly. In other words, the Automatic-Module-Name entry makes for a better contract regarding the name of an automatic module. The first version that Guava added this entry is 23.2:
Changelog
Added JPMS module name com.google.common for Guava.
...
However, the most recent version (as of writing this answer) is 26.0.
More information about automatic modules can be found:
in the Javadoc of ModuleFinder.of(Path...)
this section of The State of the Module System
and this Stack Overflow question

How do I include a single dependency in my JAR with Gradle?

I'm starting with Gradle and I was wondering how do I include a single dependency (TeamSpeak API in my case) into my JAR so that it could be available at the runtime.
Here is a part of my build.gradle :
apply plugin: 'java'
compileJava {
sourceCompatibility = '1.8'
options.encoding = 'UTF-8'
}
jar {
manifest {
attributes 'Class-Path': '.......'
}
from {
* What should I put here ? *
}
}
dependencies {
compile group: 'org.hibernate', name: 'hibernate-core', version: '4.3.7.Final'
compile group: 'org.spigotmc', name: 'spigot', version: '1.8-R0.1-RELEASE'
// Many other dependencies, all available at runtime...
// This one isn't. So I need to include it into my JAR :
compile group: 'com.github.theholywaffle', name: 'teamspeak3-api', version: '+'
}
Thanks for your help :)

The easiest way is to start with a separate configuration for the dependencies you want to include. I know you only asked about a single jar but this solution will work if you add more dependencies to your new configuration. Maven has a well known name for this sort of thing called provided, so that is what we will use.
configurations {
provided
// Make compile extend from our provided configuration so that things added to bundled end up on the compile classpath
compile.extendsFrom(provided)
}
dependencies {
provided group: 'org.spigotmc', name: 'spigot', version: '1.8-R0.1-RELEASE'
}
jar {
// Include all of the jars from the bundled configuration in our jar
from configurations.provided.asFileTree.files.collect { zipTree(it) }
}
Using provided as the name of the configuration is also important because when the jar gets published, any dependencies you have in the providedconfiguration will show up as provided in the POM.xml that gets published with the JAR. Maven dependency resolvers will not pull down provided dependencies and users of your jar will not end up with duplicate copies of classes on the classpath. See Maven Dependency Scopes

Gradle and Lwjgl 3 Natives

I'm new to gradle and I'm trying to configure gradle with lwjgl3. Because I didn't found a repo where lwjgl3 is hosted i decided that everybody who use this project has to define the path to the lwjgl lib. I created a user.gradle file with contains the paths to the jar and to the natives.
My build.gradle looks like this at the moment.
apply plugin: 'java'
apply from: 'user.gradle'
apply plugin: 'application'
sourceCompatibility = 1.8
targetCompatibility = 1.8
mainClassName = "mp.Main"
println("LWJGL jar path is configured to: ${config.lwjgl3Jar}")
println("LWJGL natives path is configured to: ${config.lwjgl3Natives}")
repositories {
mavenCentral()
flatDir {
dir config.lwjgl3Jar
}
}
dependencies {
compile 'com.google.code.gson:gson:2.3.1'
compile 'net.java.dev.jna:jna:4.1.0'
testCompile 'junit:junit:4.+'
testCompile 'com.carrotsearch:junit-benchmarks:0.7.2'
compile name: 'lwjgl'
}
tasks.withType(Test) {
scanForTestClasses = false
include "**/*Test.class" // whatever Ant pattern matches your test class files
}
sourceSets{
main {
java {
srcDir 'src'
exclude 'mp/graphics/gl/scene/Mesh.java'
exclude 'test'
}
}
test{
java {
srcDir 'src/test'
exclude '**/UnsafeTest.java'
exclude '**/DispatchTests/*'
exclude '**/MemoryTest.java'
exclude '**/SuperFastListTest.java'
exclude '**/MatrixTest.java'
exclude '**/SimulationTest.java'
}
}
}
task wrapper(type: Wrapper) {
gradleVersion = '2.3'
}
How to set the natives? I tried it different ways. Google didn't helped me out this time. All results are related to older versions of this lib and all are using repositories. Maybe I'm missing the forest for the trees in between. Any ideas?
Best regards!
PS: Not sure if it is important: We are using different IDE's like intelliJ and Eclipse on Windows, Linux, and Mac.

I have run into the same problem and wrote a plugin for handling the natives associated with Java jar files.
http://cjstehno.github.io/gradle-natives/
It will unpack them from the jar files so that you can use them and deploy them in your project.

I solved the problem for me. The problem for was that I didn't knew how to configure gradle to use the natives. Normally I set the the classpath in the run config. However:
The very simple solution how to set the classpath with gradle:
Apply the java plugin and use the function:
run {
systemProperty 'java.library.path', 'path to ur natives')
}
The simply run your application via gradle and it should work.
There were so many solutions by searching for "lwjgl gradle natives" that I didn't found the right one :-)
Hope the solution helps somebody.