Why does Kotlin JDK8 also include Kotlin JDK7 on the classpath? - java

I'm using Kotlin to build a web service and I stumbled upon what I consider to be a strange curiosity. With this build.gradle:
group 'com.example'
version '0.1.0'
buildscript {
ext.kotlinVersion = '1.2.71'
repositories {
mavenCentral()
}
dependencies {
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
}
}
apply plugin: 'kotlin'
sourceCompatibility = 1.8
repositories {
mavenCentral()
}
dependencies {
compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlinVersion"
compile 'com.fasterxml.jackson.module:jackson-module-kotlin:2.9.8'
}
compileKotlin {
kotlinOptions.jvmTarget = "1.8"
}
compileTestKotlin {
kotlinOptions.jvmTarget = "1.8"
}
I get this error during compilation:
w: Runtime JAR files in the classpath should have the same version. These files were found in the classpath:
.../kotlin-stdlib-jdk8-1.2.71.jar (version 1.2)
.../kotlin-stdlib-jdk7-1.2.71.jar (version 1.2)
.../kotlin-reflect-1.3.10.jar (version 1.3)
.../kotlin-stdlib-1.3.10.jar (version 1.3)
.../kotlin-stdlib-common-1.3.10.jar (version 1.3)
OK, no problem, jackson-module-kotlin is pulling in the kotlin 1.3 dependencies. I can exclude them. But the bit that caught my attention was the second line. kotlin-stdlib-jdk8 is also pulling in kotlin-stdlib-jdk7. In fact, I can exclude it and everything still runs as expected:
compile("org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlinVersion") {
exclude group: "org.jetbrains.kotlin", module: "kotlin-stdlib-jdk7"
}
Why is kotlin-stdlib-jdk8 pulling onto my classpath the seemingly unnecessary kotlin-stdlib-jdk7?

The warning you see during the compilation happens because jackson-module-kotlin:2.9.8 dependency apparently brings kotlin-stdlib:1.3.10 into the classpath and that version overrides your declared dependency on 1.2.71. To avoid warning you should either migrate your project to Kotlin 1.3.x or downgrade jackson-module-kotlin dependency to some previous version which depends on Kotlin 1.2.x.
kotlin-stdlib-jdk8 is an addition on top of kotlin-stdlib-jdk7, and the latter is addition on top of kotlin-stdlib. You should not exclude these transitive dependencies, otherwise you might get runtime errors.

The kotlin-stdlib-common, kotlin-stdlib-jdk7, and kotlin-stdlib-jdk8 seem to be mutually exclusive from what I could see inside the jars. That's why you need the jdk7 artifact even if you use the jdk8.
The kotlin-stdlib-jdk7 jar only contains things that were added in JDK7 like AutoCloseable and other internal apis. This is not included in the JDK8 artifact, which only include things added in JDK8.
If you don't use the use or closeFinally global functions, your code should work fine without the jdk7 artifact, but there is no real reason to exclude this jar IMHO.

Related

Gradle project is not able to find JavaFX Application class despite adding JavaFX plugin

I am new to both Gradle and JavaFX. I have added the JavaFX plugin to my build.gradle following this and this. However, my main class Library.java is not able to detect the Application class of JavaFX when I am trying to extend it.
build.gradle
plugins {
// Apply the java-library plugin to add support for Java Library
id 'java-library'
id 'application'
id 'org.openjfx.javafxplugin' version '0.0.8'
}
repositories {
// Use jcenter for resolving dependencies.
// You can declare any Maven/Ivy/file repository here.
jcenter()
mavenCentral()
}
dependencies {
// This dependency is exported to consumers, that is to say found on their compile classpath.
api 'org.apache.commons:commons-math3:3.6.1'
// This dependency is used internally, and not exposed to consumers on their own compile classpath.
implementation 'com.google.guava:guava:28.0-jre'
// Use JUnit test framework
testImplementation 'junit:junit:4.12'
}
jar {
manifest {
attributes 'Main-Class': 'Chess.Library'
}
}
mainClassName = 'Chess.Library'
Screenshot of Library Class
There's no Application from javafx package at all. What am I missing here?
I am using Spring Tool Suite 4.0 as my IDE with Buildship Gradle plugin if that's of any help. I am also running on Oracle Java 13
Edit 1:
I have added the changes suggested and this is how my build.gradle now looks
plugins {
// Apply the java-library plugin to add support for Java Library
id 'java-library'
id 'application'
id 'org.openjfx.javafxplugin' version '0.0.8'
}
repositories {
// Use jcenter for resolving dependencies.
// You can declare any Maven/Ivy/file repository here.
jcenter()
mavenCentral()
}
dependencies {
// This dependency is exported to consumers, that is to say found on their compile classpath.
api 'org.apache.commons:commons-math3:3.6.1'
// This dependency is used internally, and not exposed to consumers on their own compile classpath.
implementation 'com.google.guava:guava:28.0-jre'
// Use JUnit test framework
testImplementation 'junit:junit:4.12'
}
jar {
manifest {
attributes 'Main-Class': 'Chess.Library'
}
}
javafx {
version = "13"
modules = [ 'javafx.controls' ]
}
mainClassName = 'Chess.Library'
But the problem is still there
I also checked my Project and External Dependencies, there are all the libraries except for javafx
I fixed the issue myself although not sure what was causing it, but my project's buildpath had an unbounded Java 13. Fixing that and restarting the IDE took care of it

Android Gradle ResolutionStrategy force stil downloads previous version of lib

I have forced in my gradle to download this version of jsr305 as follows :
resolutionStrategy.force 'com.google.code.findbugs:jsr305:3.0.1'
I see that when I try to compile the gradle is resolving the version :
Inspite of that I see that during gradle sync the older versions (2.0.1 & 1.3.9) are still getting downloaded :
I am getting compile errors as follows :
com.android.build.api.transform.TransformException:
Error while generating the main dex list.
com.android.tools.r8.errors.CompilationError: Program type already present: javax.annotation.CheckForNull
Program type already present: javax.annotation.CheckForNull
I did a module level search and found that the CheckForNull.java is present at multiple places in
jsr305/2.0.1
jsr305/3.0.1
jsr305/1.3.9
I have tried deleting ./gradle folder and resync the project. I see that gradle still downloads the previous jsr305 version.
These are my dependencies in gradle :
implementation "com.facebook.react:react-native:${versions.reactNative}"
implementation ("com.google.code.findbugs:annotations:3.0.1") {
exclude group: 'net.jcip', module: 'jcip-annotations'
}
My questions :
Why is Gradle still downloading the older version of jsr305 ?
And in spite of the jsr305 version getting resolved why is multidex throwing that error ?
Created a test project that shows the behavior where the old lib versions are downloaded even after the forced resolution:
https://github.com/vineyugave/scratchpad
Also you can see the gradle scan here :
https://scans.gradle.com/s/tzrobr2zuar3c/dependencies?dependencies=jsr&expandAll
module :firstlib references implementation "com.google.code.findbugs:jsr305:2.0.0",
which should possibly be implementation "com.google.code.findbugs:jsr305:3.0.2" ...but the other one build.gradle does not really match the question, because it lacks react-native.
the dependencies of module :app should look alike (only the changes):
dependencies {
implementation "com.android.support:appcompat-v7:28.0.0"
implementation "com.android.support:recyclerview-v7:28.0.0"
implementation "com.android.support:support-v4:28.0.0"
implementation ("com.facebook.react:react-native:0.20.1") {
exclude group: "com.android.support", module: "recyclerview-v7"
exclude group: "com.android.support", module: "support-v4"
}
//noinspection GradleDependency
implementation "com.google.guava:guava:24.1-android"
}
configurations.all {
resolutionStrategy.force "com.google.code.findbugs:jsr305:3.0.2"
resolutionStrategy.force "com.google.guava:guava:24.1-android"
}
it's downloading elder versions, because they would need to be explicitly excluded from the dependencies, which demand them (as demonstrated above). one can list them all with ./gradlew app:dependencies and then exclude them accordingly.
task :app:transformClassesWithMultidexlistForDebug failed, because of support-library version conflicts caused by react-native (already fixed in the above example).
when moving those jniLibs from armeabi into armeabi-v7a, it wouldn't complain about a missing stripping tool anymore. however, then they wouldn't be loaded on arm64-v8a anymore.

Hibernate core being included from spring boot

I have a gradle project that has the following dependencies:
dependencies {
compile("com.googlecode.json-simple:json-simple:1.1.1")
compile("org.hibernate:hibernate-c3p0:5.2.12.Final")
compile("mysql:mysql-connector-java:5.1.44")
compile("org.springframework.boot:spring-boot-starter-aop")
compile("org.springframework.boot:spring-boot-starter-web")
compile group: 'org.springframework.boot', name: 'spring-boot-starter-log4j2'
}
And has the following to apply the spring boot plugin:
apply plugin: 'org.springframework.boot'
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:1.5.9.RELEASE")
}
}
The problem I am having is that when I include the spring boot plugin, an older version of hibernate-core seems to be being imported into my project (5.0.12.Final). But my code uses the 5.2.12.Final hibernate-core library.
I can't understand exactly why the hibernate core library comes with the spring boot plugin, as I can't see it listed in its dependencies on maven central, however when I remove that dependency, the older version of hibernate seems to disappear.
I've tried excluding the module when declaring the dependency but that doesn't seem to be syntactically correct when excluding in the buildscript section.
Has anyone else had this problem? Any workarounds to exclude that version? Or maybe my setup all together is wrong.. Any help would be much appreciated :)
Finally figured this one out after many hours/
Seems obvious now after a bit more research, the problem was due to spring boots own dependency management, so all I have to do is specify the version of a particular module I want to use (if spring boot already includes it), and it worked! Here is what I added to my build.xml file
dependencyManagement {
dependencies {
dependency 'org.hibernate:hibernate-core:5.2.12.Final'
}
}

What version of a library does gradle use by default?

I previously I had these dependancies defined in my gradle.build:
dependencies {
compile 'com.amazonaws:aws-java-sdk-core'
compile 'com.amazonaws:aws-java-sdk-s3'
compile 'com.amazonaws:aws-java-sdk-dynamodb'
My (incorrect?) assumption was that gradle would just use the latest versions.
But some packages seemed to not be in the version gradle was using:
I changed my dependencies list to have specific versions like this and it solved the issue above:
dependencies {
compile 'com.amazonaws:aws-java-sdk-core:1.11.106'
compile 'com.amazonaws:aws-java-sdk-s3:1.11.106'
compile 'com.amazonaws:aws-java-sdk-dynamodb:1.11.106'
So Im guess gradle was pulling the wrong version? What does it do if you don't specify a version and how do I see what version its using?

NoClassDefFoundError at Runtime with Gradle

I'm using gradle as the JavaFX plugin.
Everything works perfectly even after building and runnig the excecutable at distribution/, except with one class: CloseableHttpClient
For several purposes I create the following object like this:
CloseableHttpClient client = HttpClients.createDefault();
Running the program in the IDE is no problem, everything works fine. But if I build and try to run the .exe-File I get the following Throwable-StackTrace:
java.lang.NoClassDefFoundError: Could not initialize class org.apache.http.conn.ssl.SSLConnectionSocketFactory
at org.apache.http.impl.client.HttpClientBuilder.build(HttpClientBuilder.java:955)
at org.apache.http.impl.client.HttpClients.createDefault(HttpClients.java:58)
at ch.itcb.tools.lom.util.JsonSimpleUtil.http(JsonSimpleUtil.java:29)...
I really don't understand that. How can it be that just this class doesn't get found, but all my other classes do?
My build.gradle file:
apply plugin: 'java'
apply plugin: 'eclipse'
apply from: 'javafx.plugin'
sourceCompatibility = 1.8
version = '0.1'
jar {
manifest {
attributes 'Implementation-Title': 'LogoffManager',
'Implementation-Version': version
}
}
repositories {
mavenCentral()
}
dependencies {
compile fileTree(dir: 'lib', include: ['*.jar'])
compile 'ch.qos.logback:logback-classic:1.1.3'
compile 'org.apache.httpcomponents:httpclient:4.5.1'
compile 'com.googlecode.json-simple:json-simple:1.1'
compile group: 'commons-collections', name: 'commons-collections', version: '3.2'
testCompile group: 'junit', name: 'junit', version: '4.+'
}
test {
systemProperties 'property': 'value'
}
uploadArchives {
repositories {
flatDir {
dirs 'repos'
}
}
}
Please write a comment if you need more information. Thx.
it's a good question, which I came across just now while researching examples of the many ways Java developers can end up with class path fun :-)
I started with a minimal version of your build.gradle (including only what's directly relevant), specifically:
plugins {
id 'java'
}
sourceCompatibility = 1.8
repositories {
mavenCentral()
}
jar {
manifest {
attributes 'Main-Class': 'com.oliverlockwood.Main'
}
}
dependencies {
compile 'org.apache.httpcomponents:httpclient:4.5.1'
}
My 'Main' class, in this context, uses your code example, i.e.:
package com.oliverlockwood;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
public class Main {
public static void main(String[] args) {
CloseableHttpClient client = HttpClients.createDefault();
}
}
At this stage, I can run gradle clean build followed by java -jar build/libs/33106520.jar (my project was named after this StackOverflow question) and I see this:
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/http/impl/client/HttpClients
at com.oliverlockwood.Main.main(Main.java:8)
Caused by: java.lang.ClassNotFoundException: org.apache.http.impl.client.HttpClients
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
This is subtly different from your error, but before we dig and reproduce that, let me emphasise something: both this error and the one you're seeing are caused at runtime when the classloader is unable to find a class that it needs. There's quite a good blog post here with some more details about the difference between compile-time classpath and runtime classpaths.
If I run gradle dependencies I can see the runtime dependencies for my project:
runtime - Runtime classpath for source set 'main'.
\--- org.apache.httpcomponents:httpclient:4.5.1
+--- org.apache.httpcomponents:httpcore:4.4.3
+--- commons-logging:commons-logging:1.2
\--- commons-codec:commons-codec:1.9
I added these manually one-by-one to my runtime classpath. (For the record, this isn't generally considered good practice; but for the sake of the experiment, I copied these jars to my build/libs folder and ran with java -cp build/libs/33106520.jar:build/libs/* com.oliverlockwood.Main. Interestingly enough, this wasn't able to reproduce your exact problem. To recap:
Without org.apache.httpcomponents:httpclient available at runtime, then we fail because the HttpClients jar is not found.
With org.apache.httpcomponents:httpclient:4.5.1 available at runtime, then your problem does not manifest - and I note that the class your build fails to find (org.apache.http.conn.ssl.SSLConnectionSocketFactory) is part of this same Apache library, which is very suspicious indeed.
My suspicion is then that your runtime classpath contains a different version of the Apache httpclient library. Since there's a whole lotta versions out there, I'm not going to test every single combination, so I will instead leave you with the following advice.
If you want to fully understand the root cause of your issue, then identify exactly which jars (including their versions) are present in your error-case runtime classpath, including any jars that are packaged inside yours if you're creating a fat jar (more on this in point 3). It'd be great if you shared these details here; root cause analysis usually helps everyone to understand better :-)
Where possible, avoid using dependencies in the manner of compile fileTree(dir: 'lib', include: ['*.jar']). Managed dependencies based on a repository such as Maven or JCenter are much easier to work with consistently than dependencies in a random directory. If these are internal libraries that you don't want to publish to an open-source artifact repository, then it may be worth setting up a local Nexus instance or similar.
Consider producing a "fat jar" instead of a "thin jar" - this means that all runtime dependencies are packaged in the jar that you build. There's a good Shadow plugin for Gradle that I'd recommend - with this in place in my build.gradle, and running gradle clean shadow, I was able to run java -jar just fine without needing to manually add anything to my classpath.
For Spring boot users, this can be solved with one line of code. I am using Gradle/Kotlin, so:
id("org.springframework.boot") version "2.5.5"
inside the plugins {} section of your build.gradle.kts
For more information visit the Spring Boot Gradle Plugin Reference Guide.
For my case, I turned on my InteliJ after 3 months, got some runtime errors like noclassdeffounderror. I have to *** refresh gradle ***, then the errors are gone.

Categories

Resources