Groovy: writing dynamically compiled class to disc

In my app I need to compile classes / scripts in runtime.

as a Class:

Class<? extends LoginAdapter> clazz = groovyClassLoader.loadClass name
LoginAdapter la = clazz.newInstance id, logo

or as a Closure:

Closure action = groovyShell.evaluate( script, name ) as Closure

Both ways work like charm.

Now I need to be able to write the compiled classes/scripts to some persistant storage (disc) and later restore them back without compiling from scratch.

How can this be done?

For those who might be interested, this is my programming kata:

class Base {
  String answer() { null }
  String question() { 'WHAT IS.... ?' }
}

class ClazzSpec extends Specification {

  def "test compile"() {
    given:
    String packageName = 'some.pckg'
    String body = """
package $packageName

class SomeClass extends Base {
  Closure cl = { a -> println a }
  @Override String answer(){ '42' }
  String json( m ){ JsonOutput.toJson( m ) }
  String longOne( int times ){ 
    times.times{ sleep 100 }
    'done'
  }
}
"""

    CompilerConfiguration cc = new CompilerConfiguration( targetDirectory:new File( './out' ) )
    ImportCustomizer imp = new ImportCustomizer()
    imp.addStarImports 'groovy.json', Base.package.name
    cc.addCompilationCustomizers imp, new ASTTransformationCustomizer( value:1, TimedInterrupt )

    new Compiler( cc ).compile packageName + '.SomeClass', body

    File base = new File( './out' )

    GroovyClassLoader gcl = new GroovyClassLoader()
    gcl.addClasspath './out'
    Class clazz = gcl.loadClass 'some.pckg.SomeClass'

    when:
    def inst = clazz.newInstance()

    then:
    inst.question() == 'WHAT IS.... ?'
    inst.answer() == '42'
    inst.json( [ q:42 ] ) == '{"q":42}'
    inst.longOne( 2 ) == 'done'

    when:
    inst.longOne 11

    then:
    thrown TimeoutException
  }

}