Inconsistent build classes package structure with gradle java pugin - gradle

I am trying to run a simple gradle build with just one line in build.gradle:
apply plugin: 'java'
Java file is placed under- src/main/java/hello/Hello.java
When I run build.gradle, compiled Hello.class is generated under
build/classes/java/main/hello/Hello.class
What am I expecting is:
build/classes/main/java/hello/Hello.class
Hello.java-
package hello;
class Hello{
public static void main(String args[]){
System.out.println("Hello Java");
}
}
Can someone please explain this? Thanks.

This changed between Gradle 3.x and 4.x.
The reason we went with build/classes/java/main vs build/classes/main/java is that it was less likely to break in strange ways with builds and plugins that hardcoded the path to build/classes/main or snuck outputs into build/classes/main.
from Gradle forum discussion

Related

Spring Boot Gradle build fails with "Execution failed for task 'bootWarMainClassName'

I have a multi-project gradle build with Spring Boot structured per default gradle conventions.
root
-- common
-- src/main/java
-- bootproject
-- src/main/java
My current project is to (A) upgrade gradle from 5.x to 7.3.x and (B) use embedded tomcat with Spring Boot.
This is a project that has existed for many years and is Spring Boot but has always been deployed traditionally as a WAR file in Tomcat.
I have upgraded gradle to 7.3.3 following the gradle migration guide and have "common" building correctly (java-library). I am now trying to make "bootproject" build correctly again. I have migrated my build.gradle, and compilation happens correctly now but upon executing 'gradlew sub-project:build' I get the error:
Execution failed for task ':tx-main:bootWarMainClassName'.
java.lang.IllegalArgumentException (no error message)
My ROOT build.gradle is simple:
plugins {
id "org.springframework.boot" version "2.6.3"
}
subprojects {
apply plugin: 'java'
group = 'com.blah'
version = '2.1.1'
repositories {
mavenCentral()
}
There is a library sub-project (common) that builds fine.
The Spring Boot subproject build.gradle is:
plugins {
id 'org.springframework.boot'
id 'io.spring.dependency-management'
}
dependencies {
implementation project(path:':common', configuration:'default')
implementation 'org.springframework.boot:spring-boot-starter-web'
implementation ...
}
The main class was originally set up to make the app conventionally deployed (extends SpringBootServletInitializer), but has been replaced with (taken directly from docs):
package com.blah;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
The compilation works, this class appears to be in the build/classpath so I don't understand why Gradle-Spring-Boot is not finding it. I have also tried explicitly identifying the class with the same result.
Unfortunately I find little documentation about multi-project gradle builds so I suspect that is part of the problem. Hopefully someone here can point me in the right direction as to what is wrong.
Thanks
I discovered the issue here. We have custom code in /buildSrc that is apparently causing this.

.kts script in a Gradle project

I have a Kotlin Gradle project.
If I create a .kts file it runs in InteliJ alright except when it is in the /src/main/kotlin folder.
IDEA highlights the whole file in red.
Gradle throws out compilation exception.
The exception is
...src/main/kotlin/test.kts: (3, 1): Cannot access script base class 'kotlin.script.templates.standard.ScriptTemplateWithArgs'. Check your module classpath for missing or conflicting dependencies`.
What is the problem?
My build.gradle:
plugins {
id 'org.jetbrains.kotlin.jvm' version '1.3.0-rc-131'
}
group 'kotlin.tutorials.coroutines'
version '1.0-SNAPSHOT'
repositories {
maven { url 'http://dl.bintray.com/kotlin/kotlin-eap' }
mavenCentral()
jcenter()
maven { url "https://dl.bintray.com/kotlin/ktor" }
}
ext.ktor_version = '1.0.0-alpha-1'
ext.coroutines_version = '0.30.2-eap13'
dependencies {
compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
compile "io.ktor:ktor-server-netty:$ktor_version"
compile "ch.qos.logback:logback-classic:1.2.3"
//KTOR features
compile "io.ktor:ktor-jackson:$ktor_version"
compile "io.ktor:ktor-auth:$ktor_version"
compile "io.ktor:ktor-auth-jwt:$ktor_version"
compile "io.ktor:ktor-freemarker:$ktor_version"
compile "io.ktor:ktor-html-builder:$ktor_version"
}
compileKotlin.kotlinOptions.jvmTarget = "1.8"
compileTestKotlin.kotlinOptions.jvmTarget = "1.8"
.kts files should go to the src/main/resources folder since src/main/kotlin is for .kt files.
Scripts are a completely different animal in this sense, and you should use something like KtsRunner to execute them.
Related question is here.
If you just want to use scripts from IDEA, then you should use Scratch files which are supported out of the box.
The solution turned out to be very straight forward.
The compiler could not find utility classes that are usually added to any Kotlin script classpath. Adding one dependency to my build.gradle fixed it:
dependencies {
compile "org.jetbrains.kotlin:kotlin-scripting-jvm"
}
P.S.
I created 2 tickets to improve Kotlin script support in InteliJ:
https://youtrack.jetbrains.com/issue/KT-27542
https://youtrack.jetbrains.com/issue/KT-27544
If you care about those features, please vote them up!

How to share boilerplate Kotlin configuration across multiple Gradle projects?

The typical Kotlin configuration in a Gradle project is very boilerplate, and I'm looking for a way of abstracting it out into an external build script so that it can be reused.
I have a working solution (below), but it feels like a bit of a hack as the kotlin-gradle-plugin doesn't work out of the box this way.
It's messy to apply any non-standard plugin from an external script as you can't apply the plugin by id, i.e.
apply plugin: 'kotlin' will result in Plugin with id 'kotlin' not found.
The simple (well, usually) workaround is to apply by the fully qualified classname of the plugin, i.e.
apply plugin: org.jetbrains.kotlin.gradle.plugin.KotlinPluginWrapper
which in this case throws a nice little exception indicating that the plugin probably wasn't meant to be called this way:
Failed to determine source cofiguration of kotlin plugin.
Can not download core. Please verify that this or any parent project
contains 'kotlin-gradle-plugin' in buildscript's classpath configuration.
So I managed to hack together a plugin (just a modified version of the real plugin) which forces it to find the plugin from the current buildscript.
kotlin.gradle
buildscript {
ext.kotlin_version = "1.0.3"
repositories {
jcenter()
}
dependencies {
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
}
}
dependencies {
compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
compile "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
}
apply plugin: CustomKotlinPlugin
import org.jetbrains.kotlin.gradle.plugin.CleanUpBuildListener
import org.jetbrains.kotlin.gradle.plugin.KotlinBasePluginWrapper
import org.jetbrains.kotlin.gradle.plugin.KotlinPlugin
import org.jetbrains.kotlin.gradle.tasks.KotlinTasksProvider
/**
* Wrapper around the Kotlin plugin wrapper (this code is largely a refactoring of KotlinBasePluginWrapper).
* This is required because the default behaviour expects the kotlin plugin to be applied from the project,
* not from an external buildscript.
*/
class CustomKotlinPlugin extends KotlinBasePluginWrapper {
#Override
void apply(Project project) {
// use String literal as KOTLIN_COMPILER_ENVIRONMENT_KEEPALIVE_PROPERTY constant isn't available
System.setProperty("kotlin.environment.keepalive", "true")
// just use the kotlin version defined in this script
project.extensions.extraProperties?.set("kotlin.gradle.plugin.version", project.property('kotlin_version'))
// get the plugin using the current buildscript
def plugin = getPlugin(this.class.classLoader, project.buildscript)
plugin.apply(project)
def cleanUpBuildListener = new CleanUpBuildListener(this.class.classLoader, project)
cleanUpBuildListener.buildStarted()
project.gradle.addBuildListener(cleanUpBuildListener)
}
#Override
Plugin<Project> getPlugin(ClassLoader pluginClassLoader, ScriptHandler scriptHandler){
return new KotlinPlugin(scriptHandler, new KotlinTasksProvider(pluginClassLoader));
}
}
This can then be applied in any project (i.e. apply from: "kotlin.gradle") and you're up and running for Kotlin development.
It works, and I haven't had any issues yet, but I'm wondering if there is a better way? I'm not really keen on merging in changes to the plugin every time there's a new version of Kotlin.
Check out the nebula-kotlin-plugin. It seems very close to what you're trying to achieve there.
The problem here is that there is a known gradle bug about the inability to apply plugins by id from init scripts. That's why you need to use fully qualified class name as a workaround.
E.g. I have the following in the init script and it works:
apply plugin: org.jetbrains.kotlin.gradle.plugin.KotlinPlatformJvmPlugin
By the way, I created a gradle plugin for preparing custom gradle distributions with common setup defined in init script - custom-gradle-dist. It works perfectly for my projects, e.g. a build.gradle for a library project looks like this (this is a complete file, all repository, apply plugin, dependencies etc setup is defined in the init script):
dependencies {
compile 'org.springframework.kafka:spring-kafka'
}

call java function in gradle script

I have a java class which does some kind of functionality, one of these function returns something that I need to use it into gradle script to set the project properties.
I had achieved it by creating an artifact of project and used that artifact by adding it into classpath, that gave me accessibility of that class and function.
buildscript {
repositories {
jcenter()
maven{
url 'http:localhost:8081/artifactory/temp'
}
}
dependencies {
classpath "utility:sampleutility:1.0"
}
}
import com.polsys.utility.MyUtil
dependencies {
compile 'org.slf4j:slf4j-api:1.7.13'
compile 'HRP:'+new MyUtil().callMe()+':1.0'
//callme function returns the name of artifact.
testCompile 'junit:junit:4.12'
}
Now, I had achieved it by the way as mentioned above that is by creating artifact, add that artifact into classpath, then import classes and use function. Is this any way by which I can call functions of current project? so I can merge that functionality which is available in the artifact into current project.
Simple way is to put your Java/Groovy code under buildSrc dir. Gradle will compile it and you'll be able to call this code from your buildscript. Check https://docs.gradle.org/current/userguide/custom_plugins.html and related docs.
To make your java code available to gradle script you need to have your java code under the directory hierarchy given below:
ProjectRootDirectory
buildSrc
src
main
groovy/java
YourPackages(in my case java packages and classes)
This is the path where gradle script looking for external plugins. Now you can import and access classes into gradle script(you will not end up with "unable to resolve class" error).

Gradle artifactory plugin saying "Cannot cast object 'org.jfrog.gradle.plugin.artifactory.dsl.ArtifactoryPluginConvention'..."

Here's the configuration to get the artifactory plugin:
buildscript {
repositories {
mavenCentral()
maven { url 'http://jcenter.bintray.com' }
}
dependencies {
classpath group:'org.jfrog.buildinfo', name: 'build-info-extractor-gradle', version: '3.0.1'
}
}
apply plugin:'com.jfrog.artifactory'
apply plugin:'ivy-publish'
...some publish spec stuff...
I run gradle (2.3) and I get:
> Failed to apply plugin [id 'com.jfrog.artifactory']
> Cannot cast object 'org.jfrog.gradle.plugin.artifactory.dsl.ArtifactoryPluginConvention#6b6c7be4' with class 'org.jfrog.gradle.plugin.artifactory.dsl.ArtifactoryPluginConvention' to class 'org.jfrog.gradle.plugin.artifactory.dsl.ArtifactoryPluginConvention'
Certainly looks like a classpath issue, but I literally have this project and a sibling project using this same set of gradle/artifactory configurations and one works and the other does not. Both are part of the same top level project. Same JDK (1.8.0_20). Same Gradle. Same everything.
I'm baffled...
The problem was that when I added the various bits to the sibling project that meant I had two projects defining the buildscript {} section.
buildscript {
...
dependencies {
classpath group:'org.jfrog.buildinfo', name: 'build-info-extractor-gradle', version: '3.0.1'
}
}
Apparently that caused two different versions of the dependency to exist in the classpath, hence the error.
The solution was to move the buildscript bit into the master project so those dependencies are only defined once:
buildscript {
repositories {
maven { url "https://plugins.gradle.org/m2/" }
}
dependencies {
classpath group:'org.jfrog.buildinfo', name: 'build-info-extractor-gradle', version: '3.0.1'
}
}
Here's another potential cause. All of this looks to be a problem with rival classloaders defining the class. The full qualified classes include the loader. so, load A foo.bar is not loader B foo.bar and crossing that divide is a complex dance requiring interfaces and careful definition.
So, when using the Jenkins artifactory plugin to build your gradle project with the gradle artifactory plugin, you must add the usesPlugin or jenkins plugin will generate an init script which adds the gradle plugin on to a class loader.
def server = Artifactory.server "artifactory"
def rtGradle = Artifactory.newGradleBuild()
rtGradle.usesPlugin = true // Artifactory plugin already defined in build script
...
My problem was, desktop build OK, jenkins build shows this post's problem
I was getting a similar exception when building with Jenkins. For me the conflict was with Jenkin's version and the version in the Build script:
To address this the Artifactory section of the build has a flag you can check specifying that you want to use the version from the gradle file:
This fixed my issue. Hope it helps.
I had a similar problem. Gradle seems to try to reach across and do some checking or evaluation across siblings. I have a top level settings.gradle with 10 or so subprojects.
The fix for me was to put the buildscript block and dependencies at the top level build.gradle and put it in each of the individual subprojects build.gradle files where needed.
My guess as to the reason this works is that the plugin gets loaded in the parent which will be a parent classloader, then each child project inherits that classloader such that the declaration in the lower child script uses that classloaders class and CCE does not occur. The problem is they are the same class, but not assignable since the different classloaders per subproject if nothing is declared at the top. This was Gradle 2.4, and using IntelliJ 14.
In case it helps someone, I got the same error, but for a different reason.
I had the following in my build.gradle:
dependencies {
classpath "org.jfrog.buildinfo:build-info-extractor-gradle:+"
}
At some point the artifactory plugin updated itself from version 3.x to version 4.x while building, because no specific version was specified for the dependency. After it updated I got the error (Could not find any convention object of type ArtifactoryPluginConvention).
I guess the problem was that the rest of the configuration in my build script doesn't work with the new plugin version. Setting the dependency to use version 3.x fixed the problem for me:
dependencies {
classpath "org.jfrog.buildinfo:build-info-extractor-gradle:3.+"
}
While the currently accepted answer correctly identifies the cause of this issue, the proposed solution doesn't work when you still need to be able to build individual subprojects (because then of course they no longer have access to the buildscript defined repositories and dependencies). The solution that worked for me was to have identical buildscript blocks in each of my subprojects, that seemed to be the key. Any variations would cause the original error.
I got the same exception thrown by bamboo:
'org.jfrog.gradle.plugin.artifactory.dsl.ArtifactoryPluginConvention#18eb2827' with class 'org.jfrog.gradle.plugin.artifactory.dsl.ArtifactoryPluginConvention' to class 'org.jfrog.gradle.plugin.artifactory.dsl.ArtifactoryPluginConvention'
Since the bamboo Bamboo Artifactory Plugin by default looks for the gradle.propeties file in each sub-project module, it has to be provided there.
There is no need for publishing logic in the build.gradle file since the Bamboo Artifactory plugin will read the gradle.properties file for each module respectively, containing:
group=com.example
artifactId=your-project
version=1.0.0
The reason that I got the ArtifactoryPluginConvention exception thrown was that my configured build plan on Bamboo was misconfigured.
With misconfigured, the build ordered of the tasks was not correct. Have a look at your bamboo building tasks/preferably clone a Bamboo plan that is already working.

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