Unlock hundreds more features
Save your Quiz to the Dashboard
View and Export Results
Use AI to Create Quizzes and Analyse Results

OR
Sign inSign in with Facebook
Sign inSign in with Google
Quizzes > Quizzes for Business > Technology

Take the Java Developer Assessment Quiz

Assess Your Core Java Development Skills Now

Difficulty: Moderate
Questions: 20
Learning OutcomesStudy Material
Colorful paper art depicting elements related to Java Developer Assessment Quiz

Looking to evaluate your Java expertise? The Java Developer Assessment Quiz offers a challenging Java quiz to test programming fundamentals and advanced topics. Ideal for students, educators, or hiring teams to gauge coding skills, it helps uncover strengths in OOP, collections, and concurrency. This assessment can be freely modified in our editor to match any learning or hiring need. Explore similar Java Fundamentals Quiz, Basic Java Knowledge Test, and dive into more quizzes to expand your learning journey.

Which of these best illustrates the concept of encapsulation in Java?
Using private fields with public getters and setters.
Using multiple inheritance.
Overloading constructors.
Declaring a class as final.
Encapsulation is about restricting direct access to an object's data and providing controlled access through methods. Using private fields with public getters and setters hides implementation details and enforces access rules.
Which Java Collection interface does not allow duplicate elements?
Map
Queue
Set
List
The Set interface prohibits duplicate elements, ensuring each element is unique. Other collections like List and Queue allow duplicates, while Map handles key-value pairs.
Which of these exceptions is unchecked in Java?
IOException
NullPointerException
SQLException
ClassNotFoundException
NullPointerException is a subclass of RuntimeException and is therefore unchecked. Checked exceptions like IOException and SQLException must be declared or handled.
How do you start a new thread of execution in Java?
Call the start() method on a Thread instance.
Call the run() method directly on a Thread instance.
Invoke the main() method of the Thread class.
Use the sleep() method on a Thread instance.
Calling start() on a Thread instance creates a new thread and then invokes its run() method asynchronously. Directly calling run() executes code on the current thread.
Which class is best suited for reading text from a file efficiently?
FileReader
FileInputStream
BufferedReader
DataInputStream
BufferedReader wraps a Reader and buffers characters for efficient reading of text data. FileReader reads one character at a time without buffering, while BufferedReader reduces I/O overhead.
What is the correct wildcard notation to allow a List of Number or any of its subclasses?
List
List
List
List
List accepts Number and any subclass of Number, ensuring type safety when reading elements. The super wildcard works in the opposite direction.
Which Java Collection class is synchronized by default?
ArrayList
LinkedList
Vector
HashSet
Vector methods are synchronized, providing thread safety by default. Other collections like ArrayList and LinkedList are not synchronized and require external synchronization.
Which class provides a thread-safe Map implementation without locking the entire map?
Hashtable
HashMap
TreeMap
ConcurrentHashMap
ConcurrentHashMap uses finer-grained locking and lock stripping to allow concurrent reads and writes without locking the entire map. Hashtable locks the entire map on each operation.
What guarantee does declaring a variable as volatile provide in Java?
Visibility of changes across threads
Lock-free initialization
Mutual exclusion
Atomicity of compound operations
The volatile keyword ensures that reads and writes to a variable are directly from and to main memory, making changes visible to all threads immediately. It does not provide atomicity for compound operations.
Which of the following is a terminal operation in the Java Streams API?
map
collect
peek
filter
collect is a terminal operation that triggers the processing of the stream and gathers the results. Methods like map and filter are intermediate operations that build the pipeline.
Which statement automatically closes resources in Java 7 and later?
A finally block
A try-with-resources statement
A try-catch block
A try-finally block
The try-with-resources statement automatically closes any AutoCloseable resources when the try block is exited. This eliminates the need for explicit finally cleanup code.
How does TreeMap differ from HashMap?
HashMap sorts entries by insertion order.
TreeMap allows null keys, HashMap does not.
HashMap uses a red-black tree for storage.
TreeMap maintains keys in sorted order.
TreeMap implements a sorted map using a red-black tree, keeping keys in ascending order. HashMap uses a hash table and does not guarantee any ordering of keys.
What is the time complexity of retrieving an element by index in LinkedList?
O(1)
O(n log n)
O(n)
O(log n)
LinkedList must traverse from the head or tail to the desired index, resulting in O(n) time. ArrayList can retrieve by index in O(1) time because it uses an array internally.
Which class supports non-blocking I/O operations introduced in Java NIO?
BufferedReader
SocketChannel
FileInputStream
Socket
SocketChannel is part of Java NIO and supports non-blocking I/O, allowing select-based multiplexing. Traditional streams and Socket block on I/O operations.
What is the default initial capacity of a HashMap when no capacity is specified?
32
8
16
64
The default initial capacity of a HashMap is 16. This capacity is doubled during resizing to maintain performance and manage the load factor.
Which API is used for composing asynchronous tasks and callbacks in Java 8 and above?
CompletableFuture
Future
RunnableFuture
ExecutorService
CompletableFuture extends Future and adds methods for chaining and composing asynchronous tasks with callbacks. Future alone does not support dependency chaining.
What is the purpose of ThreadLocal in Java?
To provide a separate variable instance per thread
To yield thread execution
To manage thread pools
To synchronize threads
ThreadLocal provides a separate copy of a variable for each thread, ensuring that concurrent threads cannot interfere with each other's values. This is useful for thread-specific context data.
How can you map a region of a file directly into memory in Java?
Using FileChannel.map()
Using Files.readAllBytes()
Using RandomAccessFile.read()
Using FileInputStream.read()
FileChannel.map() creates a MappedByteBuffer that maps a region of a file directly into memory for high-performance I/O. Other methods read into user-space buffers instead.
In a ForkJoinTask, which method is used to asynchronously schedule a subtask?
join()
submit()
fork()
invoke()
The fork() method asynchronously schedules the subtask within the ForkJoinPool. The join() method waits for completion and returns the result.
Which type of reference allows the garbage collector to reclaim the object only when memory is low?
StrongReference
WeakReference
PhantomReference
SoftReference
SoftReference objects are only reclaimed when the JVM is low on memory, making them suitable for memory-sensitive caches. WeakReferences are cleared on any GC cycle.
0
{"name":"Which of these best illustrates the concept of encapsulation in Java?", "url":"https://www.quiz-maker.com/QPREVIEW","txt":"Which of these best illustrates the concept of encapsulation in Java?, Which Java Collection interface does not allow duplicate elements?, Which of these exceptions is unchecked in Java?","img":"https://www.quiz-maker.com/3012/images/ogquiz.png"}

Learning Outcomes

  1. Evaluate proficiency in Java core concepts like OOP and collections
  2. Identify best practices for exception handling and error management
  3. Apply knowledge of concurrency and multithreading principles
  4. Demonstrate understanding of Java I/O and file operations
  5. Analyse performance optimization and memory management techniques
  6. Master efficient use of Java Streams and lambda expressions

Cheat Sheet

  1. Master Java's OOP Principles - Dive into encapsulation, inheritance, and polymorphism to build neat, modular code that's easy to maintain. Think of classes as blueprints and objects as real-world gadgets you create. These superpowers will help you craft robust applications like a coding wizard. Cornell University: CS211 Course Materials
  2. Conquer the Collections Framework - Get cozy with Lists, Sets, and Maps to stash and manage your data like a pro. Choosing the right collection can turbocharge your code's performance and memory usage. Soon you'll be juggling elements with the finesse of a circus performer. Cornell University: CS211 Course Materials
  3. Learn Rock-Solid Exception Handling - Use try-catch blocks and custom exceptions to guard against runtime surprises. Proper error handling keeps your program from crashing and makes debugging a breeze. You'll write code that bounces back from mistakes like a rubber ball. Cornell University: CS211 Course Materials
  4. Unlock Java Concurrency & Multithreading - Run multiple tasks at once to make your apps lightning-fast and responsive. Master thread creation, synchronization, and the Executor framework to avoid race conditions. With this knowledge, your code will multitask better than an octopus juggling eight tasks! Cornell University: CS211 Course Materials
  5. Get Hands-On with I/O Streams - Read and write data seamlessly using InputStream, OutputStream, Readers, and Writers. Handling files and network streams becomes a walk in the park with the right tools. Soon you'll be streaming data like a DJ spinning tracks. Cornell University: CS211 Course Materials
  6. Optimize Performance with Profiling - Profile your Java Streams to spot bottlenecks and supercharge your pipelines. Learn techniques for profiling CPU and memory usage so you can trim the fat. Your app will run smoother than a sports car on a freshly paved road. Profiling and Optimizing Java Streams
  7. Master Memory Management & Garbage Collection - Discover how Java allocates and reclaims memory behind the scenes. Tweak GC settings to prevent leaks and keep your heap in tip-top shape. You'll avoid memory pitfalls and write lean, efficient code. Cornell University: CS211 Course Materials
  8. Leverage Java Streams & Lambdas - Write concise, functional-style code that's a joy to read and maintain. Stream operations and lambda expressions help you process collections with minimal boilerplate. Get ready to code like a functional programming ninja! Clash of the Lambdas
  9. Explore Java Parallel I/O Libraries - Handle massive datasets in record time with parallel I/O strategies. Understand techniques for splitting work across threads and nodes to maximize throughput. Your data crunching will be as powerful as a supercomputer cluster. Design and Development of a Java Parallel I/O Library
  10. Stay Updated with Java's Latest Features - Keep an eye on official docs, academic papers, and community blogs to learn new APIs and best practices. Continuous learning is the secret sauce to becoming a top-tier Java developer. You'll always be armed with the freshest tricks and tools. Cornell University: CS211 Course Materials
Make a Quiz (FREE) Copy & Edit This Quiz Create a Quiz with AI

Technology Quizzes

Powered by: Quiz Maker