Most often, we need to build runnable jars for java library, and I go though several solutions, including shadow, and most of them process the dependencies as classes files in jar file which is not what we expected. and what we want are the runnable jar which includes user classes filles as well as all the dependencies jars in jar format. but in this way , we need extra classloader to load the jar libs in jar files and the following has provided the way of doing it.and I go though some most importance web pages and found three solutions for it.1. Eclipse jarinjarloader https://github.com/raisercostin/eclipse-jarinjarloader
apply plugin: 'java'
apply plugin: 'eclipse'
sourceCompatibility = 1.6
targetCompatibility = 1.6
version = "4.3.3"
processResources{
exclude '**'
}
repositories {
//jcenter()
//maven { url "http://clojars.org/repo" }
}
dependencies {
compile files('lib/jlibs-core.jar')
compile files('lib/jlibs-xml.jar')
compile files('lib/autonomyPiB.jar')
}
//add Class-Path to manifest
task addDependToManifest {
doFirst{
if (!configurations.runtime.isEmpty()) {
jar.manifest.attributes('Rsrc-Class-Path': "./ lib/" + configurations.runtime.collect { it.name }.join(' lib/'))
}
}
}
jar.dependsOn += addDependToManifest
//copy libs to output/mylibs/lib folder
task copyDependencies(type: Copy) {
from configurations.runtime
destinationDir = file('build/mylibs/lib')
}
jar.dependsOn += copyDependencies
jar{
//include contents of output dir
from "build/mylibs"
from zipTree("lib/jar-in-jar-loader.zip")
manifest {
attributes 'Implementation-Title': project.name,
'Class-Path': '.',
'Rsrc-Main-Class': 'com.test.TestA',
'Main-Class': 'org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader'
}
}
2. spring boot gradle pluginwe can also use spring boot gradle plugin to build our runnable jars.
apply plugin: 'java'
apply plugin: 'eclipse'
//setting up spring boot gradle plugin which is used for building runnable jars
buildscript {
repositories {
maven { url 'https://repo.spring.io/libs-milestone' }
}
dependencies {
classpath 'org.springframework.boot:spring-boot-gradle-plugin:1.5.4.RELEASE'
}
}
apply plugin: 'org.springframework.boot'
sourceCompatibility = 1.6
targetCompatibility = 1.6
//version = "4.3.3"
tasks.withType(JavaCompile) {
options.bootClasspath = "$JDK6_HOME/jre/lib/rt.jar"
}
if (project.hasProperty('env')) {
println "Target environment: $env"
sourceSets.main.resources.srcDir "src/main/profile/$env"
}
processResources{
exclude 'TagNames.properties'
}
repositories {
//jcenter()
//maven { url "http://clojars.org/repo" }
}
dependencies {
compile files('lib/jlibs-core.jar')
compile files('lib/jlibs-xml.jar')
compile files('lib/autonomyPiB.jar')
}
bootRepackage {
mainClass = 'com.test.TestA'
}
3. the one-jar plugin in https://github.com/rholder/gradle-one-jar and this way also works, but if we upgrade to gradle 4.0+ we need to change the OneJar.groovy writeOneJarManifestFile as some function is deprecated.
File writeOneJarManifestFile(Manifest manifest) {
File manifestFile = File.createTempFile("one-jar-manifest", ".mf")
manifestFile.deleteOnExit()
manifest.attributes.put("Main-Class", "com.simontuffs.onejar.Boot")
manifest.attributes.put("One-Jar-Main-Class", mainClass)
manifest.attributes.put("One-Jar-Show-Expand", showExpand)
manifest.attributes.put("One-Jar-Confirm-Expand", confirmExpand)
manifest.writeTo(manifestFile)
return manifestFile
}
//create a runnable jar with all the dependencies using one-jar "gradle aweSomeFunJar"
apply plugin: 'java'
apply plugin: 'eclipse'
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath 'com.github.rholder:gradle-one-jar:1.0.4'
}
}
apply plugin: 'gradle-one-jar'
sourceCompatibility = 1.6
targetCompatibility = 1.6
version = "4.3.3"
processResources{
exclude 'TagNames.properties'
}
repositories {
//jcenter()
//maven { url "http://clojars.org/repo" }
}
configurations{
fatJarBuild
}
dependencies {
compile files('lib/jlibs-core.jar')
compile files('lib/jlibs-xml.jar')
compile files('lib/autonomyPiB.jar')
fatJarBuild files('lib/jlibs-core.jar')
fatJarBuild files('lib/jlibs-xml.jar')
fatJarBuild files('lib/autonomyPiB.jar')
}
task awesomeFunJar(type: OneJar) {
mainClass = 'com.test.TestA'
}
and I found for the first solution, the runnable jar can read external properties(properties in the same folder as the jar) and for other solution we can only include all our properties in the jar files.
----------------------JarInJarLoader Manifest---------------------------
Manifest-Version: 1.0Implementation-Title: dataProcessingRsrc-Class-Path: ./ lib/jlibs-core.jar lib/jlibs-xml.jar lib/autonomyP iB.jarClass-Path: .Rsrc-Main-Class: com.test.TestAMain-Class: org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader---------------------- spring boot gradle plugin Manifest---------------------------