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Java MCQ: Which Java 9 feature allows developers to interactively evaluate code snippets? a) JavaFX b) JShell c) JConsole d) Javadoc Answer: b) JShell Explanation: JShell is a feature introduced in Java 9 that allows developers to interactively evaluate code snippets. JShell, also known as the REPL (Read-Eval-Print Loop) tool, provides an environment where developers […]

Java MCQ: What is the primary purpose of the Java Module System introduced in Java 9? a) To improve multithreading capabilities b) To encapsulate packages and improve code organization c) To replace the JDK d) To enhance the GUI framework Answer: b) To encapsulate packages and improve code organization Explanation: The primary purpose of the

Java MCQ: Which of the following best describes the purpose of the DateTimeFormatter class in Java 8? a) To convert a date-time object to a String and vice versa b) To manage time zones c) To parse legacy date formats d) To store time zone rules Answer: a) To convert a date-time object to a

Java MCQ: Which Stream API method is used to execute a terminal operation that does not produce a result but applies an action to each element? a) collect() b) reduce() c) forEach() d) map() Answer: c) forEach() Explanation: The forEach() method in the Stream API is used to execute a terminal operation that does not

Java MCQ: What does the Optional.empty() method return? a) An empty List b) An Optional containing a null value c) An Optional with no value present d) An Optional containing an empty string Answer: c) An Optional with no value present Explanation: The Optional.empty() method returns an Optional with no value present. This method is

Java MCQ: What is the purpose of the method reference in Java 8? a) To reference the name of a method without invoking it b) To create multiple instances of a method c) To allow methods to be called using reflection d) To enable functions to be passed as arguments in a lambda expression Answer:

Java MCQ: What does the reduce() method in the Stream API do? a) Filters the elements of a stream b) Combines the elements of a stream into a single result c) Converts elements of a stream to another type d) Collects the elements of a stream into a List Answer: b) Combines the elements of

Java MCQ: Which Java 8 feature allows interfaces to include methods with implementations? a) Functional interfaces b) Default methods c) Lambda expressions d) Stream API Answer: b) Default methods Explanation: Default methods in Java 8 allow interfaces to include methods with implementations. This feature was introduced to enable interface evolution without breaking existing implementations. A

Java MCQ: Which method in the Stream API is used to convert elements to another type? a) filter() b) collect() c) map() d) reduce() Answer: c) map() Explanation: The map() method in the Stream API is used to convert elements of a stream to another type. It applies the provided function to each element in

Java MCQ: What is a functional interface in Java? a) An interface with only static methods b) An interface that contains exactly one abstract method c) An interface with only one method d) An interface that cannot be extended Answer: b) An interface that contains exactly one abstract method Explanation: A functional interface in Java

Java MCQ: What is the main advantage of using lambda expressions in Java? a) They improve runtime performance b) They reduce the amount of boilerplate code required for anonymous classes c) They enforce immutability in Java classes d) They allow for multiple inheritance Answer: b) They reduce the amount of boilerplate code required for anonymous

Java MCQ: Which method in the Stream API is used to filter elements based on a predicate? a) map() b) filter() c) collect() d) reduce() Answer: b) filter() Explanation: The filter() method in the Stream API is used to filter elements based on a predicate. A predicate is a functional interface that represents a boolean-valued

Java MCQ: Which method in the Optional class is used to provide a default value if the Optional is empty? a) orElse() b) get() c) ifPresent() d) orElseThrow() Answer: a) orElse() Explanation: The orElse() method in the Optional class is used to provide a default value if the Optional is empty. This method returns the

Java MCQ: Which of the following statements is true about static methods in interfaces in Java 8? a) Static methods in interfaces can only be called on an instance of the interface b) Static methods in interfaces can be called without an instance of the interface c) Static methods in interfaces must be overridden in

Java MCQ: Which package in Java 8 provides the new Date and Time API? a) java.util.time b) java.date c) java.time d) java.timezone Answer: c) java.time Explanation: The java.time package in Java 8 provides the new Date and Time API. This API was introduced to address the shortcomings of the older java.util.Date and java.util.Calendar classes, which

Java MCQ: What is the purpose of the Optional class in Java 8? a) To replace all null checks b) To provide a container object which may or may not contain a non-null value c) To handle exceptions in a functional style d) To provide default values for method parameters Answer: b) To provide a

Java MCQ: What is the primary use of the Stream API introduced in Java 8? a) To manage files and directories b) To process collections of data in a functional style c) To handle exceptions in a new way d) To create and manage threads Answer: b) To process collections of data in a functional

Java MCQ: Which interface in Java 8 is annotated with @FunctionalInterface? a) List b) Runnable c) Comparator d) Map Answer: b) Runnable Explanation: The Runnable interface in Java is annotated with @FunctionalInterface in Java 8. A functional interface is an interface that contains exactly one abstract method. These interfaces can be used as the assignment

Java MCQ: Which feature introduced in Java 8 allows interfaces to have methods with implementations? a) Abstract methods b) Default methods c) Static methods d) Anonymous methods Answer: b) Default methods Explanation: Java 8 introduced default methods, which allow interfaces to have methods with implementations. This feature was added to enable the evolution of interfaces

Java MCQ: Which of the following is a valid example of a lambda expression in Java? a) int add(int a, int b) b) (a, b) -> a + b c) a + b => int d) lambda(int a, int b) { return a + b; } Answer: b) (a, b) -> a + b Explanation:

Java MCQ: What is the primary purpose of Java Lambda Expressions? a) To define anonymous classes b) To enable functional programming by passing behavior as an argument c) To enhance exception handling d) To manage multithreading Answer: b) To enable functional programming by passing behavior as an argument Explanation: Java Lambda Expressions were introduced in

Java MCQ: Which of the following best describes atomic variables in Java? a) Variables that are read and written atomically, ensuring thread safety without synchronization b) Variables that can be divided into smaller parts for parallel processing c) Variables that are synchronized using the synchronized keyword d) Variables that hold references to multiple objects simultaneously

Java MCQ: Which class in Java provides a mechanism for creating reentrant locks? a) ReentrantLock b) LockManager c) SynchronizedLock d) ThreadLock Answer: a) ReentrantLock Explanation: The ReentrantLock class in Java provides a mechanism for creating reentrant locks. It is part of the java.util.concurrent.locks package and is used as an alternative to the synchronized keyword for

Java MCQ: What is a Future in Java concurrency? a) A type of thread that executes tasks b) A placeholder for a result that will be available in the future c) A mechanism to run tasks in parallel d) A new Java keyword for defining multithreaded tasks Answer: b) A placeholder for a result that

Java MCQ: Which interface in Java is used to define a task that returns a result and can be executed by an ExecutorService? a) Runnable b) Callable c) Executable d) Task Answer: b) Callable Explanation: The Callable interface in Java is used to define a task that returns a result and can be executed by