The InputStream and OutputStream classes are part of the java.io package in Java. These classes are used for reading and writing data in a byte-oriented manner, making them essential for I/O operations.

When a thread tries to access a synchronized block in Java, it must first obtain the "Lock" on the object. This ensures that only one thread can execute the synchronized code block at a time, preventing race conditions.

The correct answer is getPort(). In Java, the URL class provides the getPort() method, which allows you to obtain the port number of a URL. This is useful when working with network-related tasks where you need to know the port associated with a particular URL.

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.

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.

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)).

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.

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.

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.

A thread enters the "Terminated" state in Java once its "run()" method has completed execution. In this state, the thread has finished its task and is no longer actively executing code.