How to convert all the contents of a .aar package to a .jar package?

Question

I am trying to convert a .aar package to a .jar package according to the title above. I have tried several procedures(including those mentioned here), but all without success. It seems that it is necessary to convert all the contents of the package (including resources, manifest, etc.) to .jar.

The reason for this is that I need to publish .jar files together with my library in an artifactory repository, since .aar gets the following error when referencing it in 'libs /' in the assemble process:

Execution failed for task ':integration-lib:bundleReleaseAar'.
> Direct local .aar file dependencies are not supported when building an AAR. The resulting AAR would be broken because the classes and Android resources from any local .aar file dependencies would not be packaged in the resulting AAR. 
Previous versions of the Android Gradle Plugin produce broken AARs in this case too (despite not throwing this error). The following direct local .aar file dependencies of the :integration-lib project caused this error: /Users/thomas/Projetos/mobile-integration-lib/integration-lib/libs/PPCompAndroid-v1.32.aar

I also tried to import it by creating a new module with .jar/.aar file and referencing it in the library gradle, but it is not deployed in the artifactory repository.

My Gradle library:

apply plugin: 'com.android.library'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'com.jfrog.artifactory'
apply plugin: 'maven-publish'

def application = new Application()

class Application {

    def packageName = 'com.soufan.integration-lib'
    def versionMajor = 0
    def versionMinor = 0
    def versionPatch = 27

    def versionName() {
        return (versionPatch > 0 ? "${versionMajor}.${versionMinor}.${versionPatch}" : "${versionMajor}.${versionMinor}")
    }

    def static gitVersion() {
        def process = ['/bin/bash', '-c', 'git rev-list HEAD | wc -l | xargs'].execute()
        return process.text.toInteger()
    }
}

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.0"

    defaultConfig {
        minSdkVersion 22
        targetSdkVersion 30
        versionCode application.gitVersion()
        versionName application.versionName()

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        consumerProguardFiles "consumer-rules.pro"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }

    publishing {
        publications {
            aar(MavenPublication) {
                groupId application.getPackageName()
                version application.versionName()
                artifactId project.getName()
                artifact("$buildDir/outputs/aar/${project.getName()}-release.aar")

                pom.withXml {
                    def dependenciesNode = asNode().appendNode('dependencies')

                    configurations.compile.allDependencies.each { dependency ->

                        if (dependency.group != null) {

                            def dependencyNode = dependenciesNode.appendNode('dependency')
                            dependencyNode.appendNode('groupId', dependency.group)
                            dependencyNode.appendNode('artifactId', dependency.name)
                            dependencyNode.appendNode('version', dependency.version)
                        }
                    }
                }
            }
        }
    }

    artifactory {
        contextUrl = URL_DEPLOY
        publish {
            repository {
                repoKey = DEPLOY_REPO_KEY
                username = USER_NAME
                password = API_KEY
            }
            defaults {
                publications('aar')
                publishArtifacts = true
                properties = ['qa.level': 'basic', 'dev.team': 'core']
                publishPom = true
            }
        }
    }

}


dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    implementation 'androidx.core:core-ktx:1.3.0'
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
    implementation 'com.journeyapps:zxing-android-embedded:3.6.0'
    implementation 'com.squareup.okhttp3:okhttp:4.0.1'

    // Dependencies
    implementation files('libs/NeptuneLiteApi_V2.04.00_20180329.jar')
    implementation files('libs/PPCompAndroid-v1.32.aar')
    implementation files('libs/libposdigital-1.5.1-4-release.aar')
    implementation files('libs/zoop-emv-connect-pax-a920-pos_0.10.jar')
}

My Project Gradle:

buildscript {
    ext.kotlin_version = "1.3.72"
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:4.0.1'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath "org.jfrog.buildinfo:build-info-extractor-gradle:4.10.0"
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}