What happens if we put a key object in a HashMap which exists?

The new object replaces the older object

The old object is removed from the map

It throws an exception as the key already exists in the map

If two threads access the same hashmap at the same time, what would happen?

ConcurrentModificationException

How to externally synchronize hashmap?

Collections.synchronizedMap(new HashMap<String, String>());

HashMap.synchronize(HashMap a);

HashMap a = new HashMap(); a.synchronize();

Collections.synchronize(new HashMap<String, String>());

What will be the output of the following Java code snippet? https://gyazo.com/536fd105502737a2e2f69b680f818239

{1=null, 2=null, 3=null, 4=null, 5=null}

{1=null, 5=null, 3=null, 2=null, 4=null}

If large number of items are stored in hash bucket, what happens to the internal structure?

The bucket will switch from LinkedList to BalancedTree

The bucket will increase its size by a factor of load size defined

The LinkedList will be replaced by another hashmap

Any further addition throws Overflow exception

How can we remove an object from ArrayList?

c) remove() method and using Iterator

How to remove duplicates from List?

HashSet<String> listToSet = new HashSet<String>(duplicateList);

HashSet<String> listToSet = duplicateList.toSet();

HashSet<String> listToSet = Collections.convertToSet(duplicateList);

HashSet<String> listToSet = duplicateList.getSet();

When two threads access the same ArrayList object what is the outcome of the program?

ConcurrentModificationException is thrown

Both are able to access the object

One thread is able to access the object and second thread gets Null Pointer exception

One thread is able to access the object and second thread will wait till control is passed to the second one

How is Arrays.asList() different than the standard way of initialising List?

Arrays.asList() returns a fixed length list and doesn’t allow to add or remove elements

Arrays.asList() throws compilation error

We cannot access the list returned using Arrays.asList()

What is the difference between length() and size() of ArrayList?

length() returns the capacity of ArrayList and size() returns the actual number of elements stored in the list

length() and size() return the same value

length() is not defined in ArrayList

size() is not defined in ArrayList

What does Collections.emptySet() return?

The type of Set depends on the parameter passed to the emptySet() method

What is the difference between TreeSet and SortedSet?

SortedSet is an interface; TreeSet is a concrete class

TreeSet is more efficient than SortedSet

SortedSet is more efficient than TreeSet

TreeSet is an interface; SortedSet is a concrete class

What happens if two threads simultaneously modify TreeSet?

ConcurrentModificationException is thrown

Both threads can perform action successfully

IteratorModificationException is thrown

What is the unique feature of LinkedHashSet?

It maintains the insertion order and guarantees uniqueness

It provides a way to store key values with uniqueness

The elements in the collection are linked to each other

java.util – Collections Framework-9

Authored by ANIL KUMAR

English

Professional Development

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MULTIPLE CHOICE QUESTION

20 sec • 1 pt

Which of these standard collection classes implements a dynamic array?

AbstractList

LinkedList

ArrayList

AbstractSet

MULTIPLE CHOICE QUESTION

20 sec • 1 pt

Which of these class can generate an array which can increase and decrease in size automatically?

ArrayList()

DynamicList()

LinkedList()

MallocList()

MULTIPLE CHOICE QUESTION

20 sec • 1 pt

Which of these method can be used to increase the capacity of ArrayList object manually?

Capacity()

increaseCapacity()

increasecapacity()

ensureCapacity()

MULTIPLE CHOICE QUESTION

20 sec • 1 pt

Which of these method of ArrayList class is used to obtain present size of an object?

size()

length()

index()

capacity()

MULTIPLE CHOICE QUESTION

20 sec • 1 pt

Which of these methods can be used to obtain a static array from an ArrayList object?

Array()

covertArray()

toArray()

covertoArray()

MULTIPLE CHOICE QUESTION

20 sec • 1 pt

Which of these method is used to reduce the capacity of an ArrayList object?

trim()

trimSize()

trimTosize()

trimToSize()

MULTIPLE CHOICE QUESTION

20 sec • 1 pt

What will be the output of the following Java program? https://gyazo.com/33f13b49749f6661b34ad51e60ca84b0

[A, B, C, D]

[A, D, B, C]

[A, D, C]

[A, B, C]

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java.util – Collections Framework-9

Which of these standard collection classes implements a dynamic array?

Which of these class can generate an array which can increase and decrease in size automatically?

Which of these method can be used to increase the capacity of ArrayList object manually?

Which of these method of ArrayList class is used to obtain present size of an object?

Which of these methods can be used to obtain a static array from an ArrayList object?

Which of these method is used to reduce the capacity of an ArrayList object?

What will be the output of the following Java program? https://gyazo.com/33f13b49749f6661b34ad51e60ca84b0

What will be the output of the following Java program?
https://gyazo.com/3cb2900c0b07825763f60c2bc10b0258

What will be the output of the following Java program?
https://gyazo.com/f523cd35b2806fb4fd9efca1fecf9520

What will be the output of the following Java program?
https://gyazo.com/4ea3062c5f17dbe07cfa2b9a49d379de

Access all questions and much more by creating a free account

Similar Resources on Wayground

Popular Resources on Wayground

java.util – Collections Framework-9

Which of these standard collection classes implements a dynamic array?

Which of these class can generate an array which can increase and decrease in size automatically?

Which of these method can be used to increase the capacity of ArrayList object manually?

Which of these method of ArrayList class is used to obtain present size of an object?

Which of these methods can be used to obtain a static array from an ArrayList object?

Which of these method is used to reduce the capacity of an ArrayList object?

What will be the output of the following Java program? https://gyazo.com/33f13b49749f6661b34ad51e60ca84b0

What will be the output of the following Java program?https://gyazo.com/3cb2900c0b07825763f60c2bc10b0258

What will be the output of the following Java program?https://gyazo.com/f523cd35b2806fb4fd9efca1fecf9520

What will be the output of the following Java program? https://gyazo.com/4ea3062c5f17dbe07cfa2b9a49d379de

Access all questions and much more by creating a free account

Similar Resources on Wayground

Popular Resources on Wayground

What will be the output of the following Java program?
https://gyazo.com/3cb2900c0b07825763f60c2bc10b0258

What will be the output of the following Java program?
https://gyazo.com/f523cd35b2806fb4fd9efca1fecf9520

What will be the output of the following Java program?
https://gyazo.com/4ea3062c5f17dbe07cfa2b9a49d379de