Queue without vowels:[B, C, D, F, G, H, J, K, L, M, N, P, Q, R, S, T, V, W, X, Y, Z] 例子2 importjava.util.ArrayList;importjava.util.List;importjava.util.concurrent.ConcurrentLinkedQueue;publicclassConcurrentLinkedQueueRemoveAllExample2{publicstaticvoidmain(String[] args)...
list.add(null); queue.retainAll(list); System.out.println("Queue = "+queue); } } 輸出: Exception in thread "main" java.lang.NullPointerException at java.util.TreeMap.put(TreeMap.java:563) at java.util.TreeSet.add(TreeSet.java:255) at com.javaTpoint.ConcurrentLinkedQueueRetainAllExampl...