What happens to the result of a relational operation if both operands are NaN?
- It returns false.
- It returns true.
- It throws a NaNException.
- It throws a NullPointerException.
When both operands of a relational operation are NaN, Java returns false. This behavior is consistent with the IEEE 754 floating-point standard, which defines the behavior of floating-point numbers, including NaN. Options 2, 3, and 4 are incorrect because they don't reflect the actual behavior of Java in this situation.
A thread that goes into the ________ state will not be brought back to the running state when its sleep time has elapsed or its operation is complete.
- blocked
- sleeping
- terminated
- waiting
Once a thread enters the "terminated" state, it cannot be brought back to the running state. The thread has completed its execution or has been explicitly terminated and cannot be resumed.
What will happen if an exception is not caught by any catch block?
- The exception will be automatically caught by the JVM.
- The program will continue to execute normally.
- The program will enter an infinite loop.
- The program will terminate with an error.
In Java, if an exception is not caught by any catch block within the current method, it will propagate up the call stack, and if not caught anywhere, it will lead to program termination with an error message. This is essential for identifying and handling exceptional situations in a program.
Which class is primarily used for implementing UDP sockets?
- DatagramPacket
- DatagramSocket
- ServerSocket
- Socket
In Java, the DatagramSocket class is primarily used for implementing UDP (User Datagram Protocol) sockets. It provides methods to send and receive UDP packets. The other options are not specific to UDP sockets.
What is the result of Double.POSITIVE_INFINITY == Double.POSITIVE_INFINITY in Java?
- It depends on the context of the comparison.
- It returns false.
- It returns true.
- It throws an ArithmeticException.
In Java, comparing Double.POSITIVE_INFINITY to itself using the == operator returns true. This behavior is consistent with the IEEE 754 standard, which defines the behavior of floating-point numbers. Double.POSITIVE_INFINITY is considered equal to itself. Options 2 and 3 are incorrect because they don't accurately represent the result of this comparison. Option 4 is incorrect because the comparison of infinity values is well-defined in Java.
How does the linear search algorithm find the target value in its input?
- It divides the array into two halves and checks each half separately
- It jumps to a random location and checks if the element is present there
- It starts from the first element and compares each element one by one
- It uses a mathematical formula to calculate the position of the target element
The linear search algorithm finds the target value by starting from the first element of the array and comparing each element one by one until it either finds a match or reaches the end of the array. It is a straightforward and sequential search method, which means it has a worst-case time complexity of O(n), where 'n' is the number of elements in the array.
Using ________, we can perform cleanup operations when the stream is closed.
- catch
- close
- finally
- try
In Java's Stream API, the close() method is used to perform cleanup operations when the stream is closed. This can be helpful when you need to release external resources or perform any necessary cleanup before the stream is no longer in use.
In a multi-threaded environment, which class (StringBuffer or StringBuilder) would you primarily use and why?
- Both StringBuffer and StringBuilder can be used interchangeably
- Neither StringBuffer nor StringBuilder should be used in a multi-threaded environment
- StringBuffer
- StringBuilder
In a multi-threaded environment, StringBuilder is primarily used due to its better performance. Unlike StringBuffer, StringBuilder is not synchronized, which makes it more efficient when thread safety is not a concern. StringBuffer is synchronized and is used when thread safety is required. Using both interchangeably may lead to synchronization overhead.
Which data structure is preferred for implementing Binary Search effectively?
- Array
- Binary Tree
- Hash Table
- Linked List
Binary Search is most effectively implemented with a sorted array. This is because arrays provide direct access to elements by index, which is crucial for the binary search algorithm's efficiency. Binary trees and hash tables do not provide direct index-based access, making them less suitable for binary search. Linked lists can be used, but they may not offer the same performance advantages as arrays.
Synchronized methods prevent thread interference and memory consistency errors by allowing ________ thread(s) to execute the method's entire body.
- all but one
- multiple
- no additional thread(s)
- only one
Synchronized methods in Java allow only one thread to execute the method's entire body at a time. This ensures that there is no concurrent execution, preventing thread interference and memory consistency errors. Other threads are blocked until the executing thread completes the synchronized method. This is a fundamental concept in Java for ensuring thread safety.