Java Programming

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

Java MCQ: Which of the following is true about the ExecutorService in Java? a) It allows for direct management of threads b) It is used for managing a pool of threads c) It cannot return results from submitted tasks d) It is a subclass of the Thread class Answer: b) It is used for managing

Java MCQ: What is the purpose of the wait() method in Java? a) To pause the execution of a thread indefinitely b) To release the lock held by a thread and wait until another thread notifies it c) To start a new thread d) To terminate a thread Answer: b) To release the lock held

Java MCQ: Which of the following mechanisms is used to achieve thread synchronization in Java? a) Semaphore b) Synchronized block c) Deadlock d) Thread pool Answer: b) Synchronized block Explanation: The synchronized block in Java is used to achieve thread synchronization. Synchronization is the mechanism that ensures that only one thread can access a resource

Java MCQ: Which of the following best describes the lifecycle of a Java thread? a) New, Runnable, Running, Blocked, Dead b) New, Ready, Executing, Blocked, Terminated c) New, Runnable, Blocked, Waiting, Terminated d) New, Runnable, Running, Waiting, Terminated Answer: d) New, Runnable, Running, Waiting, Terminated Explanation: The lifecycle of a Java thread consists of the

Java MCQ: Which method must be overridden when implementing the Runnable interface? a) start() b) run() c) execute() d) call() Answer: b) run() Explanation: When implementing the Runnable interface in Java, you must override the run() method. The run() method contains the code that defines the task to be executed by the thread. The Runnable

Java MCQ: What is the primary purpose of the Thread class in Java? a) To execute SQL queries b) To represent and control threads of execution in a program c) To manage file I/O operations d) To create graphical user interfaces Answer: b) To represent and control threads of execution in a program Explanation: The

Java MCQ: Can the Builder Pattern be used with Java Records? a) No, Java Records do not support the Builder Pattern b) Yes, but only through a third-party library c) Yes, by manually implementing a Builder class d) Yes, by using a built-in Java Builder API Answer: c) Yes, by manually implementing a Builder class

Java MCQ: Can you customize the default behavior of the canonical constructor in Java Records? a) No, the canonical constructor cannot be customized b) Yes, by defining a compact constructor c) Yes, by overriding the constructor method d) Yes, but only for records with a single field Answer: b) Yes, by defining a compact constructor

Java MCQ: How do you access the fields of a Java Record? a) Using getter methods like getName() and getAge() b) Using field names directly like name and age c) Using generated methods with the same name as the fields like name() and age() d) Using reflection only Answer: c) Using generated methods with the