A simple gradle build file that you can drop into your typical Netbeans java project to build the jar using gradle from the command-line.

netbeans-project-gradle.build

apply plugin: 'java'
libsDirName = '../dist'
docsDirName = '../dist'
sourceSets {
	main {
		java {
			srcDirs = ['src']
		}
	}
}
javadoc {
	failOnError = false // permissive javadoc generation
}
repositories {
	flatDir {
		dirs 'lib' // add libraries folder to build path
	}
	// jcenter() // repo for "standard" java tools like JUnit
	// mavenCentral() // repo with lots of LGPL/MIT/Apache open source libraries
}

dependencies {
	//testCompile "junit:junit:+"
	
	// import xxx.jar from the libraries folder:
	//compile name: 'xxx' 
	
	// import artifactId "libname" in groupId "zzz.xyz" from Maven repository:
	//compile "zzz.xyz:libname:version"
}