/src/main/java/org/htmlunit/WebClientInternals.java
listeners_ ;
listeners_ = Collections.synchronizedList ( new ArrayList<> ( ) ) ;
private Collection<Listener> listeners_; WebClientInternals() { } public void addListener(final Listener listener) { synchronized (this) { if (listeners_ == null) { <extra_id_0> } } listeners_.add(listener); } public void removeListener(final Listener listener) { listeners_.remove(listener);