src/main/java/com/workplacesystems/utilsj/collections/decorators/SynchronizedSortedMap.java
public Comparator<? super K> comparator() {
        return SyncUtils.synchronizeRead(lock, new Callback<Comparator<? super K>>() {
            @Override
            protected void doAction() {
                _return(getSortedMap().comparator());
            }
        });
    }
public Comparator<? super K> comparator() {
        return SyncUtils.synchronizeRead(lock, new Callback<Comparator<? super K>>() {
            @Override
            protected void doAction() {
                _return(getSortedMap().comparator());
            }
        });
    }
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