@Override public long getLastModified() {
                        synchronized (DirConfigSource.this) {
                            if ( ! checked.add(name)) {
                                doubleChecked = true;
                                DirConfigSource.this.notifyAll();
                            }
                            return super.getLastModified();
                        }
                    }
@author Tony Vaagenes
@author gjoranv
@author ollivir
container-core/src/test/java/com/yahoo/container/di/DirConfigSource.java