I'm building a jar file with Gradle. This jar file is being used as a library in another project. But when the project tries to use the jar file, a ClassNotFoundException is returned.
Caused by: java.lang.NoClassDefFoundError: com/auth0/jwt/JWT
I've included the jwt library in the gradle file building the jar:
compile group: 'com.auth0', name: 'java-jwt', version: '3.4.0'
The project using the jar can't seem to find this jar dependency in the jar.
I built the jar with the gradle command:
task fatJar(type: Jar) {
manifest {
attributes 'Implementation-Title': 'Jar File creation',
'Implementation-Version': version,
'Main-Class': 'com.group.me.name.MyJarClass'
}
baseName = project.name + '-all'
from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
with jar
exclude 'META-INF/*.RSA', 'META-INF/*.SF','META-INF/*.DSA'
}
How do I include the missing dependency in the jar?
You, generally, should not pack the dependencies inside a published JAR. It's better to declare them as dependencies in pom.xml and let the user of you JAR fetch them. It's just a good practice that should be enough.
If it's not enough, use Gradle Shadow:
plugins {
id 'com.github.johnrengelman.shadow' version '4.0.2'
}
Fat JAR is produced with shadowJar task in this case. Publishing is easy as well:
publishing {
publications {
shadow(MavenPublication) { publication ->
project.shadow.component(publication)
}
}
repositories {
maven {
url "http://your.repo"
}
}
}
I have a a fatjar, which is a deployable jar with main method defined, and which depedencies are copied via gradle.
This works fine.
I want to obsufucate/encrypt my jar.
Using proguard I can obsufucate myJar, and specify libraryjars. How do I get a farJar created from the obsufucated jar and its dependencies ?
So far I can only obsufucate the original jar, not obsufucate and bundle as fat jar.
task fatJar(type: Jar) {
manifest {
attributes 'Implementation-Title': 'Metriculous',
'Implementation-Version': version,
'Main-Class': 'au.com.metriculous.MetriculousServer'
}
baseName = project.name + '-all'
from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
with jar
}
my proguard task looks pretty much the same as the samples, the library jars don't get added to jar as fatJar. And I don't want to define lots of rules for not obsufucating injars, which I could do if I simply obsufucate the whole fatjar ?
I need to distribute one of our integration tests, it lives under src/test. So I'm using gradle to build a jar pointing to this class.
I figured this out from poking around the net:
task fatJar(type: Jar) {
zip64 = true
manifest {
attributes 'Implementation-Title': 'Gradle Jar File Example',
'Implementation-Version': 1.3,
'Main-Class': 'org.example.AnIntegrationTest'
}
from sourceSets.test.output
}
When I try running this I get the:
Error: Could not find or load main class org.example.AnIntegrationTest
The main method is there, and 'jar tf' does show me the class in the package.
What am I missing here?
Your jar file is missing test-runtime dependencies. One possible solution is to package all required dependencies into your jar as well. Note that this will increase the size of your distributable jar.
Add an additional from clause to your jar task:
task fatJar(type: Jar) {
zip64 = true
manifest {
attributes 'Implementation-Title': 'Gradle Jar File Example',
'Implementation-Version': 1.3,
'Main-Class': 'org.example.AnIntegrationTest'
}
from sourceSets.test.output
//collect all dependencies
from { configurations.testRuntime.collect { it.isDirectory() ? it : zipTree(it) } }
with jar
}
In a build.gradle script, I would perform the following task to include dependencies into a runnable application JAR file.
jar {
manifest {
attributes(
'Class-Path': configurations.compile.collect { it.getName() }.join(' '),
'Main-Class': 'org.somepackage.MyMainClass'
)
}
from configurations.compile.collect { entry -> zipTree(entry) }
}
However, in multi-project setups I was missing some dependencies in the JAR file. I ultimately discovered any dependencies specified in other project build.gradle scripts were not being included, unless the parent project had those dependencies too.
For example, Project A depends on Project B. Project B uses Google Guava. When I deployed Project A to a runnable JAR file, Google Guava would not be included and there would be runtime errors. If Project A redundantly specified Google Guava in its build.gradle script, then it runs just fine.
How can I modify my jar task above to include dependencies in multi-project setups?
I got some ideas from this post that seemed to work.
jar {
manifest {
attributes(
'Main-Class': 'com.swa.rm.pricing.reporting.ux.SaleMxReportingUI'
)
}
}
task fatJar(type: Jar) {
manifest.from jar.manifest
classifier = 'all'
from {
configurations.runtime.collect { it.isDirectory() ? it : zipTree(it) }
} {
exclude "META-INF/*.SF"
exclude "META-INF/*.DSA"
exclude "META-INF/*.RSA"
}
with jar
}
I would like my Gradle build script to add the complete Classpath to the manifest file contained in JAR file created after the build.
Example:
Manifest-Version: 1.0
Class-Path: MyProject.jar SomeLibrary.jar AnotherLib.jar
My build script already add some information to the manifest this way:
jar {
manifest {
attributes("Implementation-Title": project.name,
"Implementation-Version": version,
"Main-Class": mainClassName,
}
}
How do I get the list of dependencies to add to the manifest?
This page of Java tutorials describes more in detail how and why adding classpath to the manifest: Adding Classes to the JAR File's Classpath
Found a solution on Gradle's forum:
jar {
manifest {
attributes(
"Class-Path": configurations.compile.collect { it.getName() }.join(' '))
}
}
Source: Manifest with Classpath in Jar Task for Subprojects
In the latest versions of gradle, compile and runtime becomes deprecated. Instead, use runtimeClasspath as follows:
'Class-Path': configurations.runtimeClasspath.files.collect { it.getName() }.join(' ')
EDIT:
Note that if you are using Kotlin DSL, you can configure the manifest as follows:
configure<JavaPluginConvention> {
sourceCompatibility = JavaVersion.VERSION_1_8
targetCompatibility = JavaVersion.VERSION_1_8
manifest {
attributes(
"Manifest-Version" to "1.0",
"Main-Class" to "io.fouad.AppLauncher")
}
}
tasks.withType(Jar::class) {
manifest {
attributes["Manifest-Version"] = "1.0"
attributes["Main-Class"] = "io.fouad.AppLauncher"
}
}
Place this at the end of the buid.gradle file. Change the com.example.Main to your own Main class.
jar {
doFirst {
manifest {
if (!configurations.compile.isEmpty()) {
attributes(
'Class-Path': configurations.compile.collect{it.toURI().toString()}.join(' '),
'Main-Class': 'com.example.Main')
}
}
}
}
The top answers helped me a lot. Here is what worked for me:
jar {
manifest {
attributes "Main-Class": "your.package.classWithMain"
attributes "Class-Path": configurations.compile.collect { it.absolutePath }.join(" ")
}
}
So, instead of name, I had to use absolutePath. This may or may not work for you. Some suggest using runtime instead of compile. I used compile because, I have a compile section in dependencies in my build.gradle. So, the jar step picks up dependencies from there. The best thing to do is pick up something that you think will work, do a gradle build, then find the JAR file and expand it to find the META-INF/MANIFEST.MF file. You should be able to see all the directories separated by spaces. If not, you should try something different. Autocomplete feature of your IDE should be helpful in seeing what all methods or fields are available under configurations/compile etc. All this can be done easily in IntelliJ.
Oh.. and if you want to see where the library JARs are physically located on your disk, right click on your project->open module settings->Libraries and then click on any library.
This is another solution for Kotlin DSL (build.gradle.kts).
When running your app, the library files are supposed to be in libs/ subdirectory of the app.
tasks.jar {
manifest.attributes["Main-Class"] = "com.example.MyMainClass"
manifest.attributes["Class-Path"] = configurations
.runtimeClasspath
.get()
.joinToString(separator = " ") { file ->
"libs/${file.name}"
}
}
I know this is likely trivial for the groovy people here, but in my case, I wanted to change the location of the Class-Path in the manifest file depending on whether I was going to run in the production environment or local environment. I did this by making my build.gradle's jar section look like this:
jar {
from configurations.runtime
manifest {
attributes ('Main-Class': 'com.me.Main',
'Class-Path': configurations.runtime.files.collect { jarDir+"/$it.name" }.join(' ')
)
}
}
In this case, the argument to gradle build is passed like so:
$ gradle build -PjarDir="/opt/silly/path/"
Looks like gradle has evolved. This is another answer that looks similar to others, but there is a key difference: if you use a new keyword implementation in the dependencies, none of the other answers will work and you'll get an empty class path
dependencies {
// ensure the keyword here matches what
// you have in the jar->manifest->attributes
// that is "implementation"
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.3'
// ...
}
// by default, implementation cannot be referenced,
// this allows us to use it below
project.configurations.implementation.setCanBeResolved(true)
jar{
manifest {
attributes(
"Main-Class": "app.Program",
"Class-Path": configurations.implementation.collect { it.name }.join(' ')
)
}
dependsOn ('dependencies')
}
If your project has external library dependencies, you could copy the jars to a folder and add the classpath entries in the manifest.
def dependsDir = "${buildDir}/libs/dependencies/"
task copyDependencies(type: Copy) {
from configurations.compile
into "${dependsDir}"
}
task createJar(dependsOn: copyDependencies, type: Jar) {
manifest {
attributes('Main-Class': 'com.example.gradle.App',
'Class-Path': configurations.compile.collect { 'dependencies/' + it.getName() }.join(' ')
)
}
with jar
}
More details can be read here
I managed to create a custom Jar file with its own manifest file like so:
task createJar(type : Jar) {
manifest {
attributes(
'Manifest-Version': "1.0",
'Main-Class': "org.springframework.boot.loader.JarLauncher",
'Start-Class': "com.my.app.AppApplication",
'Spring-Boot-Version': "2.2.4.RELEASE",
'Spring-Boot-Classes': "BOOT-INF/classes/",
'Spring-Boot-Lib': "BOOT-INF/lib/"
)
}
def originDir = file("${buildDir}/unpacked")
def destinationFile = "${buildDir}/repackaged/${project.name}-${version}"
entryCompression ZipEntryCompression.STORED // no compression in case there are files in BOOT-INF/lib
archiveName destinationFile
from originDir
archiveFile
}
I had a similar yet not identical problem.
I was publishing my lib jar L into Artifactory, and later fetching it as a dependency of module M, but the transitive dependencies, the ones which L need for compile and runtime, did not arrive with it. It took me sometime to realize that my jar was published into Artifactory with an empty pom file, hence gradle was not able to know which are L's transitive dependencies to be fetched.
The missing piece was an instruction, in the L's build.gradle, to publish the pom.
As often with gradle, the connection between the name of the instruction, and its meaning, is completely:
apply plugin: 'maven'
uploadArchives {
repositories {
mavenDeployer {
repository(url: "file://localhost/tmp/myRepo/")
}
}
}
Source: uploading_to_maven_repositories