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Unable to use outside dependencies within custom gradle plugin implementation

When attempting to use outside dependencies within a custom gradle plugin I'm building, I am not able to import or use them in any regard.
I've attempted to specify in both the build script and the normal dependencies closure my dependencies. I'm using Gradle 5.5 (wrapper script) and I am using the buildSrc method of writing a custom gradle plugin.
// Necessary if loading custom plugins
apply plugin: 'java-gradle-plugin'
buildscript {
repositories {
mavenCentral()
jcenter()
}
dependencies {
classpath 'com.google.code.gson:gson:2.8.5'
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
group 'com.foo'
sourceCompatibility = 1.8
targetCompatibility = 1.8
repositories {
mavenCentral()
jcenter()
}
gradlePlugin {
plugins {
greeterPlugin {
id = 'com.foo.dbcreation-plugin'
implementationClass = 'com.foo.dbcreation.DbCreation'
}
}
}
dependencies {
compile 'com.google.code.gson:gson:2.8.5'
}

There are quite a few issues I see here.
buildscript does not control the dependencies for your plugin implementation.
Use the plugins {} DSL block to apply plugins. It is the preferred way: https://docs.gradle.org/current/userguide/plugins.html#sec:plugins_block
Should be using implementation over compile since compile is deprecated as noted in https://docs.gradle.org/current/userguide/java_plugin.html#tab:configurations
With that said, your Gradle file should be like:
plugins {
id 'java-gradle-plugin'
id 'eclipse'
id 'idea'
}
group 'com.foo'
sourceCompatibility = 1.8
targetCompatibility = 1.8
repositories {
mavenCentral()
jcenter()
}
gradlePlugin {
plugins {
greeterPlugin {
id = 'com.foo.dbcreation-plugin'
implementationClass = 'com.foo.dbcreation.DbCreation'
}
}
}
dependencies {
implementation 'com.google.code.gson:gson:2.8.5'
}

I figured out what my issue was. For projects being built using the buildSrc directory, you need to have the build.gradle file reside in that directory instead of the root project directory (where the build.gradle normally lives). I just converted the project to a normal gradle project and it works just fine.

Include distribution folder of frontend build in the JAR with Gradle

I am a gradle beginner and I am struggling to include the frontend distribution build folder in the backend jar (I use Spring Boot and the frontend is an ionic app). In the backend.gradle, I configured the jar-Task that should include the frontend-build folder (called www) into build folder of the backend. The jar task runs through, but the desired artifacts are not present in the backend-build folder and therefore not in the final jar. Would be glad for any help.
project structure:
project
build.gradle
settings.gradle
backend
--> backend.gradle
frontend
--> frontend.gradle
settings.gradle
include 'backend'
include 'frontend'
rootProject.children.each {
it.buildFileName = it.name + '.gradle'
}
build.gradle
allprojects {
buildscript {
repositories {
mavenCentral()
}
}
apply plugin: 'idea'
repositories {
mavenCentral()
}
}
frontend.gradle
plugins {
id "com.moowork.node" version "1.2.0"
}
task clean(dependsOn: 'npm_run_clean') {
}
task build(dependsOn: 'npm_run_build') {
}
backend.gradle
buildscript {
ext {
springBootVersion = '1.5.8.RELEASE'
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
apply plugin: 'java'
apply plugin: 'org.springframework.boot'
group = 'ch.renewinkler'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8
jar {
from('frontend/www') {
into('public')
}
}
processResources.dependsOn(':frontend:build')
dependencies {
compile('org.springframework.boot:spring-boot-starter-web')
testCompile('org.springframework.boot:spring-boot-starter-test')
}

You need to tell gradle that the jar task depends on the frontend's build task, otherwise it could run the jar file before the build task, and thus have nothing to include in the jar.
It's also a better idea to refer to projects by their name, instead of using absolute paths:
jar {
dependsOn(':frontend:build')
into('public') {
from "${project(':frontend').projectDir}/www"
}
}

Unable to Build Spring RestService Tutorial in IntelliJ

I am attempting to work through the Spring Framework Restful Web Service creation tutorial(https://spring.io/guides/gs/rest-service/#scratch) using Gradle and IntelliJ. I have followed everything to the letter but being fairly new to Spring, IntelliJ, and Java in general I'm unsure how to go about further debugging my issue.
When I attempt to build my project I receive a few errors stating "Java: package org.springframework.web.bind.annotation does not exist." I'm guessing I'm missing a library reference but am unsure how to check and include it.
buildscript {
ext {
springBootVersion = '1.3.5.RELEASE'
}
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
classpath("org.springframework:spring-web:${springBootVersion}")
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'spring-boot'
jar {
baseName = 'hello_springtest'
version = '0.0.1-SNAPSHOT'
}
repositories {
mavenCentral()
}
sourceCompatibility = 1.8
targetCompatibility = 1.8
dependencies {
compile('org.springframework.boot:spring-boot-starter-web')
testCompile('org.springframework.boot:spring-boot-starter-test')
}
task wrapper(type: Wrapper) {
gradleVersion = '2.3'
}
eclipse {
classpath {
containers.remove('org.eclipse.jdt.launching.JRE_CONTAINER')
containers 'org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8'
}
}
Just thought I'd add some additional information. I'm still seeing the errors and am unsure why but my project does report that the build was successful. When I attempt to make the project however that's when I receive the annotation does not exist error.

You have some dependency in your builds script, which seems to me redundant and causes Gradle to look up for additional dependencies.
Just remove this dependency from your buildscript dependencies
classpath("org.springframework:spring-web:${springBootVersion}")
I see no reason to use it within your buildscript.

build using gradle instead of eclipse

I'm very new to whole tomcat/spring/eclipse world.
I used gradle a little bit for android projects.
This is a project with tomcat/spring/eclipse and I 'd like to build it with gradle.
I copied a build.gradle file from one of tutorial on the web.
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:1.2.5.RELEASE")
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'spring-boot'
jar {
baseName = 'gs-serving-web-content'
version = '0.1.0'
}
repositories {
mavenCentral()
}
sourceCompatibility = 1.7
targetCompatibility = 1.7
dependencies {
compile("org.springframework.boot:spring-boot-starter-thymeleaf")
testCompile("junit:junit")
}
task wrapper(type: Wrapper) {
gradleVersion = '2.3'
}
Now I run > gradle build and I see tons of errors which says 'org.springframework.*** does not exist'
I guess I need to somehow tell gradle to include *.jar files under
WebContent/WEB-INF/lib directory, but don't know how.
Please let me know if need to supply more info.

To add all jar files from WebContent/WEB-INF/lib and subfolders you must include the first line:
dependencies {
compile(fileTree(dir: "WebContent/WEB-INF/lib", include: "**/*.jar"))
compile("org.springframework.boot:spring-boot-starter-thymeleaf")
testCompile("junit:junit")
}

How to compile project with Google Checkstyle rules with gradle?

I am trying to use Google checkstyle configuration (https://github.com/checkstyle/checkstyle/blob/master/src/main/resources/google_checks.xml) but I am constantly getting an error on gradle check:
Unable to create a Checker: cannot initialize module TreeWalker - Unable to instantiate EmptyCatchBlock
I used Gradle to build the project. Below is my gradle.build.
apply plugin: 'java'
apply plugin: 'idea'
apply plugin: 'checkstyle'
sourceCompatibility = 1.8
version = '1.0'
checkstyle {
toolVersion = "6.3"
}
task "create-dirs" << {
sourceSets*.java.srcDirs*.each { it.mkdirs() }
sourceSets*.resources.srcDirs*.each { it.mkdirs() }
}
jar {
manifest {
attributes 'Implementation-Title': 'xyz',
'Implementation-Version': 0.01
}
}
repositories {
mavenCentral()
}
dependencies {
compile (
['org.apache.logging.log4j:log4j-api:2.2'],
['org.apache.logging.log4j:log4j-core:2.2']
)
testCompile(
['junit:junit:4.11'],
['org.mockito:mockito-core:1.+']
)
}
test {
systemProperties 'property': 'value'
}
uploadArchives {
repositories {
flatDir {
dirs 'repos'
}
}
}
Also, when I try to add XML config file to Checkstyle plugin in IDEA I get similar error but with a stack trace:
org.infernus.idea.checkstyle.exception.CheckStylePluginException: <html><b>The CheckStyle rules file could not be loaded.</b><br>cannot initialize module TreeWalker - Unable to instantiate EmptyCatchBlock</html>
at org.infernus.idea.checkstyle.checker.CheckerFactory.blacklistAndShowMessage(CheckerFactory.java:234)
at org.infernus.idea.checkstyle.checker.CheckerFactory.createChecker(CheckerFactory.java:188)
at org.infernus.idea.checkstyle.checker.CheckerFactory.getOrCreateCachedChecker(CheckerFactory.java:98)
at org.infernus.idea.checkstyle.checker.CheckerFactory.getChecker(CheckerFactory.java:73)
at org.infernus.idea.checkstyle.checker.CheckerFactory.getChecker(CheckerFactory.java:41)
I cannot figure out what am I doing wrong. Any help would be appreciated.
Gradle version: 2.2

You can add this configuration into your build.gradle file:
configurations {
checkstyleOverride
}
dependencies {
checkstyleOverride('com.puppycrawl.tools:checkstyle:6.11.2')
}
tasks.withType(Checkstyle) {
checkstyleClasspath = project.configurations.checkstyleOverride
}
Enjoy!

The problem lies in the fact that com.puppycrawl.tools.checkstyle.checks.blocks.EmptyCatchBlockCheck was indeed added to checkstyle but for version 6.4-SNAPSHOT. As it can be seen in checkstyle repository (pom.xml history) version 6.4-SNAPSHOT was introduced on the 02.02.2015 and EmptyCatchBlockCheck class was created on 18.02.2015.
Gradle still uses version 6.3 as in the following log extract:
:checkstyleMain
Download https://repo1.maven.org/maven2/com/puppycrawl/tools/checkstyle/6.3/checkstyle-6.3.pom
So there's simply no class You'd like to use.
According to the docs checkstyle classpath can be specified with checkstyleClasspath property - you can try to set it up manually.
I've also prepared a demo with 6.4-SNAPSHOT version, it can be found here. Checkstyle jar was built with mvn clean package with source taken from this repo.

Here is an approach that works with the (currently) latest versions of Gradle & Checkstyle (Gradle 6.1.1 & Checkstyle 8.29):
plugins {
id 'java'
id 'checkstyle'
}
configurations {
checkstyleConfig
}
dependencies {
checkstyleConfig("com.puppycrawl.tools:checkstyle:8.29") { transitive = false }
}
checkstyle {
toolVersion '8.29'
config = resources.text.fromArchiveEntry(configurations.checkstyleConfig, 'google_checks.xml')
}
Note that the Checkstyle dependency excludes transitive dependencies, otherwise the resources.text.fromArchiveEntry will fail since multiple JAR files will be present, and it will be unable to select a single one.