Collecting & Aggregating Streams QuizJ8 Home « Collecting & Aggregating Streams Quiz

The questions in this quiz on Java are on the topics covered in the Streams section of the site. The table below lists the lesson used for each quiz, a description of the lesson content and the quiz number and questions associated with that lesson.

Lesson Summary

Click on a lesson in the table to go to that lesson for a refresher on the topics for that quiz.

Click on a quiz in the table to go straight to the quiz for a particular lesson.

Generics Lessons Description Quiz Info.
Lesson 1 - Introducing StreamsIn our first lesson on on Streams we test your knowledge of the topics covered in the Introducing Streams lesson.Quiz1
9 questions
Lesson 2 - Stream PipelinesIn this lesson on streams we look at stream pipelines and how they work.Quiz2
9 questions
Lesson 3 - Stream Operations OverviewIn this lesson on streams we present an overview of the intermediate and terminal operations available.Quiz3
9 questions
Lesson 4 - Array Type StreamsIn this streams lesson we look at the various ways of creating streams from arrays.Quiz4
8 questions
Lesson 5 - Numeric StreamsIn this lesson on streams we look at numeric streams and the operations associated with them.Quiz5
7 questions
Lesson 6 - Other Stream CreationIn this lesson we take a final look at stream creation by creating streams from files, functions and iterations and also find out about creating infinite streams.Quiz6
9 questions
Lesson 7 - Finding & MatchingIn this streams lesson we look at the various ways of finding and matching values within our streams.Quiz7
9 questions
Lesson 8 - Reduction OperationsIn this streams lesson we look at reduction operations and how to use them.Quiz8
7 questions
Lesson 9 - Stream CollectorsIn this lesson we take a high level look at stream collectors by investigating the Collector<T,A,R> interface and the Collectors class implementation of it.Quiz9
8 questions
Lesson 10 - Collecting & Aggregating StreamsIn this lesson we look at how to create collections and aggregations from our streams.This quiz.
8 questions
Lesson 11 - Grouping & Partitioning StreamsThis lesson on streams is all about grouping & partitioning our streams.Quiz11
9 questions
Lesson 12 - Parallel StreamsThis lesson is all about parallel streams.Quiz12
8 questions

Streams Quiz 10

The quiz below tests your knowledge of the material learnt in Streams - Lesson 10 - Collecting & Aggregating Streams.

Question 1 : Which Collectors method concatenates input elements into a String?
- The <code>joining()</code> method of the <code>Collectors</code> class concatenates input elements into a <code>String</code>.
Question 2 : The toMap() method can deal with duplicate keys?
- There is an override of the <code>toMap()</code> method which takes a third parameter to deal with duplicate keys.
Question 3 : Which of these methods requires a comparator?
- Both the <code>max()</code> and <code>maxBy()</code> methods require a comparator.
Question 4 : Streams can handle collections but not their implementations?
- Streams can handle collection implementations using the <code>toCollection()</code> static method of the <code>Collectors</code> class to pass a stream to an implementation such as <code>LinkedHashSet</code>.
Question 5 : Which interface does the Collectors class offer implementations of?
- The <code>Collectors</code> class implements the <code>Collector</code> interface.
Question 6 : Methods of the Collectors class are imported statically?
- Methods of the <code>Collectors</code> class ARE imported statically, as all methods in this class are static.
Question 7 : In which order are elements returned from the no parameter sorted() method of the Stream interface?
- The elements are returned in NATURAL order from the no parameter <code>sorted()</code> method of the <code>Stream</code> interface.
Question 8 : The sorted() method of the Stream interface is a terminal operation?
- The <code>sorted()</code> method of the <code>Stream</code> is NOT a terminal operation.
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What's Next?

In the next quiz we test your knowledge of grouping and partitioning our streams.