Sample of failure when calling the LOG generated by the @slf4j annotation.

TestLogASTAnnotation.groovy

import groovy.util.logging.Slf4j

/**
 * Created by User: ngandriau - Date: 7/6/13 - Time: 5:52 PM
 */
@Slf4j(value = "LOG")
class TestLogASTAnnotation {

    static TestLogASTAnnotation staticInstanceOfMyClass = new TestLogASTAnnotation()

    TestLogASTAnnotation() {
        // !!! This call fails
        // Caused by: java.lang.NullPointerException: Cannot invoke method info() on null object
        LOG.info "constructor call"
    }

    def test2Log(){
        // This call works
        LOG.info "test in instance method"
    }

    public static void main(String[] args) {
        // This call works
        LOG.debug "test in static method"

        staticInstanceOfMyClass.test2Log()
    }
}

// It's a problem with static initializer ordering. This is a simple fix.

import groovy.util.logging.Slf4j

/**

• Created by User: ngandriau - Date: 7/6/13 - Time: 5:52 PM
  */
  @slf4j(value = "LOG")
  class TestLogASTAnnotation {

  // This must not have an initializer because LOG gets added as the last static member of the class.
  static TestLogASTAnnotation staticInstanceOfMyClass

  // This can go anywhere (and refer to any static member, regardless of where it is placed)
  // even before the member declaration above and it will still get executed after all the
  // static member initializers.
  static {
  staticInstanceOfMyClass = new TestLogASTAnnotation()
  }

  TestLogASTAnnotation() {
  // !!! This call fails
  // Caused by: java.lang.NullPointerException: Cannot invoke method info() on null object
  // logger.info "constructor call"
  LOG.info "constructor call"
  }

  def test2Log(){
  // This call works
  LOG.info "test in instance method"
  }

  public static void main(String[] args) {
  // This call works
  LOG.debug "test in static method"

  staticInstanceOfMyClass.test2Log()
  

  }
  }