How to build mrm.jar using Gradle

apply plugin: 'java'
apply plugin: 'idea'

sourceCompatibility = 1.5
// version = '1.0'
jar.baseName = 'mrm'
gems_common_lib='../apps/build/ext/components/bndl_gems/build/gems_common/build/libs'

buildDate = new Date()
changes = 'Removed the usage of gems_common'

defaultTasks 'clean', 'build'

sourceSets {
    main {
        java {
            srcDir 'src'
        }
        resources {
            srcDir 'src/resources'
        }
    }
}

repositories {
    mavenCentral()
}

dependencies {
    compile files("${gems_common_lib}/gems_common.jar")
    testCompile group: 'junit', name: 'junit', version: '4.+'
}

jar {
    manifest {
        attributes  'Manifest-Version': 1.0,
                    'Created-By': 'David Chang',
                    'Created-Date': buildDate,
                    'Change-Log': changes
    }
}