Java Programming, 1st Edition by Pearson

Set Containers 325

HashSet, 317 Set algebraic operations, 318 TreeSet, 317

LinkedHashSet, 317 Set interface, 317

Multiple-choice Questions

1. What is the output?

HashSet set = new HashSet();

set.add(1);

set.add(2);

set.add(1);

System.out.println(set);

a. [1,2,1] b. [1,2]

c. [1] d. IllegalArgumentException

2. What is the output?

HashSet set1 = new HashSet();

set1.add(1);

set1.add(2);

set1.add(1);

HashSet set2 = new HashSet();

set2.add(4);

set2.add(3);

set1.addAll(set2);

System.out.println(set1);

a. [1,2,3,4] b. [1,2,1,4,3]

c. [1,2,4,3] d. [2,1,4,3]

3. What is the output?

HashSet set1 = new HashSet();

set1.add(1);

set1.add(3);

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