자격증/OCJP_ExamC

QUESTION 25

IT grow. 2018. 7. 24. 03:10
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QUESTION 25
Given:
public class Person {
private name;
public Person(String name) {
this.name = name;
}
public int hashCode() {
return 420;
}
}
Which statement is true?
A. The time to find the value from HashMap with a Person key depends on the size of the map.
B. Deleting a Person key from a HashMap will delete all map entries for all keys of type Person.
C. Inserting a second Person object into a HashSet will cause the first Person object to be removed as a duplicate.
D. The time to determine whether a Person object is contained in a HashSet is constant and does NOT depend on the size of the map.
Solution : A



plus imformation


when use to Hashmap class in java 

1. A HashMap contains values based on the key.

2.It contains only unique elements.

3.It may have one null key and multiple null values.

4.It maintains no order.



https://www.javatpoint.com/java-hashmap

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