What is the impact of using Lambda expressions on Java's Garbage Collection?
- Lambda-generated objects are never collected by Garbage Collection.
- Lambda-generated objects may lead to more frequent Garbage Collection.
- Lambdas are directly managed by Garbage Collection.
- Lambdas have no impact on Garbage Collection.
Lambda expressions in Java can generate additional objects, known as "captured variables" or "closure instances." These objects may lead to more frequent Garbage Collection, as they are subject to memory management. However, Java's Garbage Collection system is designed to efficiently handle short-lived objects, so the impact is often minimal. Understanding this impact is essential for optimizing memory usage in applications that heavily use Lambdas.
The method ________ of the RandomAccessFile class sets the file-pointer offset.
- moveFilePointer()
- seek()
- setFilePointer()
- setPointerOffset()
The method seek() of the RandomAccessFile class in Java is used to set the file-pointer offset to a specified location within the file. It allows you to navigate within the file and start reading or writing data from that position.
What happens if a superclass is not serializable but its subclass is, and we serialize an object of the subclass?
- Only the subclass fields will be serialized.
- Serialization will fail.
- Serialization will proceed without errors.
- The superclass fields will be serialized, but not the subclass fields.
If a superclass is not serializable but its subclass is, attempting to serialize an object of the subclass will result in a java.io.NotSerializableException. This happens because the superclass needs to be serializable for the serialization process to work correctly. The other options are incorrect, as they imply successful serialization without issues.
What is the purpose of using URL Encoding in Java?
- To encrypt URLs for secure communication
- To ensure special characters are transmitted properly
- To optimize URL routing for faster navigation
- To shorten URLs for better performance
URL Encoding in Java is used to ensure that special characters, such as spaces or symbols, are properly transmitted in URLs. It replaces reserved characters with escape sequences to prevent issues in URL handling and parsing. The other options do not accurately describe the purpose of URL Encoding.
Which class is commonly used for reading characters from a file in Java?
- FileInputReader
- FileOutputReader
- FileReader
- FileWriter
In Java, the commonly used class for reading characters from a file is FileReader. It is part of the java.io package and is specifically designed for character input. Other options like FileWriter, FileInputReader, and FileOutputReader are not standard classes in Java for file reading.
To obtain a string representation of a primitive data type, you can use the static valueOf method of the ________ class.
- Double
- Float
- Integer
- String
In Java, you can use the static valueOf method of the Integer class to obtain a string representation of a primitive data type. For example, Integer.valueOf(42) will return the string "42". The other options do not provide this specific functionality.
How does the Merge Sort algorithm behave in terms of space complexity?
- It has a space complexity of O(1) as it sorts the array in place without using additional memory.
- It has a space complexity of O(log n) because it divides the array into smaller subarrays, reducing memory usage.
- It has a space complexity of O(n) because it creates a temporary array to hold the merged subarrays.
- It has a space complexity of O(n^2) due to the need for additional memory for merging subarrays.
Merge Sort has a space complexity of O(n) because it creates a temporary array to hold the merged subarrays during the sorting process. Unlike some other sorting algorithms like Quick Sort, Merge Sort does not use a constant amount of extra memory (O(1)) or divide the memory usage logarithmically (O(log n)).
What does the Serializable interface contain?
- A set of methods for creating new objects
- A set of methods for mathematical calculations
- A set of methods for serializing objects
- A set of methods for sorting objects
The Serializable interface in Java does not contain any methods. Instead, it serves as a marker interface, indicating that the class implementing it can be serialized. Serialization allows objects to be converted into a byte stream for storage or transmission. It's used for objects that need to be saved to a file or sent over a network.
The process of defining a new exception by extending an existing exception class is known as ________.
- Customization of exception
- Exception chaining
- Exception creation
- Exception handling
In Java, when you define a new exception by extending an existing exception class, it's called "Customization of exception." This process allows you to create your own exception classes that suit your application's specific needs while maintaining compatibility with Java's exception hierarchy.
Which of the following methods is used to read data from an InputStream object connected to a socket?
- read()
- readData()
- readFromSocket()
- readStream()
To read data from an InputStream object connected to a socket, you typically use the read() method. This method reads a single byte of data and returns an integer representation of that byte. You can then cast it to the appropriate data type. The other options are not standard methods for reading from sockets.