Java Maps Review

Front

Which of the following statement about Set is true? A HashSet cannot have a null value. Set allows duplicate values. Set allows null values but only single occurrence. Set extends the Java.util.collection interface.

Back

Set extends the Java.util.collection interface.

Front

Which interface of the java.util package offers the specified behavior: -Entries are organized as key/value pairs. -Duplicate entries replace old entries. -Entries are sorted using a Comparator or the Comparable interface?

Back

SortedMap

Front

Back

{1=C, 2=JavaEE, 3=Python, 4=PHP}

Front

Back

{null=null, a=null, b=JavaSE, c=PHP, d=Python}

Front

Back

5

Front

Which of the following TreeMap instantiations would create a TreeMap that could store String-Integer pairs? Options: TreeMap<String,Integer> map; map = new TreeMap <String,Integer>();, TreeMap<Integer,String> map; map = new TreeMap <Integer,String>();, TreeMap<Double,String> map; map = new TreeMap <Double,String>();, TreeMap<Boolean,String> map; map = new TreeMap <Boolean,String>();

Back

TreeMap<String,Integer> map;
map = new TreeMap <String,Integer>();

Front

Which of the following Map methods will add a pair to a Map? Options: add(), get(), set(), put(), append()

Back

put()

Front

Which of the following is an interface?
Options:
ArrayList,
HashSet,
TreeMap,
Collection,
LinkedList

Back

Collection

Front

Which of the following is a child of SortedMap? ArrayList, HashMap, TreeMap, Map, LinkedList

Back

TreeMap

Front

What is the output by the code below?

Back

null