Which JavaFX layout class allows you to arrange components in a resizable grid of rows and columns?
- BorderPane
- FlowPane
- GridPane
- HBox
The GridPane layout class in JavaFX is used to create a grid-based layout where components can be arranged in rows and columns. This layout is suitable for resizable grids, making it ideal for creating forms and other structured interfaces. Components can be placed in specific grid cells, allowing for precise positioning and alignment.
How does Java determine which overloaded method to call?
- Java calls the method randomly, as it cannot determine which one to call.
- Java calls the method that exactly matches the arguments provided during the method call.
- Java calls the method with the fewest number of parameters.
- Java calls the method with the most number of parameters.
Java determines which overloaded method to call by examining the number and types of arguments provided during the method call. It looks for the method that exactly matches the provided arguments. If no exact match is found, it results in a compilation error.
Which exception might be thrown when trying to create a new Socket instance?
- IOException
- NetworkException
- SocketCreationException
- SocketException
When attempting to create a new Socket instance, you may encounter an IOException if there's an issue with the network connection or if the host is unreachable. It's a common exception in socket programming. The other options are not standard exceptions related to socket creation.
In Java, if an if statement does not have any braces {}, only the ________ line after the if condition is considered part of the if block.
- first
- last
- middle
- next
In Java, when an if statement does not have braces {}, only the first line of code immediately following the if condition is considered part of the if block. Any subsequent lines of code are executed outside of the if block. This can lead to unexpected behavior if not used carefully.
What is the return type of the map() function in Java Streams API?
- List
- Stream
- int
- void
The map() function in Java Streams API transforms the elements of a stream and returns a new stream of the transformed elements. Therefore, the return type of map() is Stream. It allows you to apply a function to each element and map them to a new value or type.
BufferedReader uses a default buffer size of ________ characters unless specified otherwise.
- 1024
- 4096
- 512
- 8192
BufferedReader uses a default buffer size of 1024 characters unless you specify a different size during its initialization. Choosing an appropriate buffer size can optimize input operations.
What is the correct syntax for the switch statement in Java?
- select(expr) { }
- switch { case: ... break; }
- switch(expr) { case: ... }
- switch(expression) { }
In Java, the correct syntax for a switch statement is: switch (expression) { case value1: // Code for value1 break; case value2: // Code for value2 break; // Add more cases as needed default: // Code to execute if no case matches } The switch statement is used for multi-way branching based on the value of the expression.
How does Java store a two-dimensional array in memory?
- Java stores a two-dimensional array as a contiguous block of memory, with rows and columns laid out sequentially.
- Java stores a two-dimensional array as a set of separate arrays, where each row is a distinct array stored in memory.
- Java stores a two-dimensional array as a single array where each element points to another array holding the row data.
- Java uses a linked list data structure to store elements in a two-dimensional array, providing dynamic memory allocation.
In Java, a two-dimensional array is stored as a contiguous block of memory, with rows and columns laid out sequentially. This ensures efficient memory access and better cache performance. The other options are not how Java stores two-dimensional arrays and may lead to inefficiencies.
In which case(s) does Binary Search perform in O(1) time complexity?
- When the array is empty
- When the target element is at the first index of the array
- When the target element is at the middle of the array
- When the target element is not present in the array
Binary Search performs in O(1) time complexity when the target element is at the first index of the sorted array. In this case, it can directly access the element and return it. When the array is empty, it still performs in O(1) time complexity as there are no elements to search. In other cases, it performs in O(log n) time complexity, where 'n' is the number of elements in the array.
Which exception type must be explicitly handled or declared to be thrown in a method?
- Checked exceptions
- Errors
- None of the above
- Unchecked exceptions (Runtime)
In Java, checked exceptions (which extend the Exception class but not RuntimeException) must be explicitly handled or declared to be thrown in a method. This requirement ensures that the code handles potentially problematic situations.
Which of the following event types is not a mouse event in JavaFX?
- KeyEvent
- MouseDragEvent
- MouseEvent
- TouchEvent
In JavaFX, KeyEvent is not a mouse event; it represents keyboard events. Mouse events, such as MouseEvent and MouseDragEvent, are related to mouse input. TouchEvent deals with touch input. Understanding the distinction between these event types is essential when working with JavaFX event handling.
The process of hiding the internal details of a class and showing only the things that are necessary is known as ________.
- Abstraction
- Encapsulation
- Inheritance
- Polymorphism
In Java, encapsulation is the process of hiding the internal details of a class and exposing only the essential parts. It helps in maintaining the integrity of the class and prevents unauthorized access to its data. This concept is fundamental to object-oriented programming.