In Java, you can cancel a task submitted to an ExecutorService using the cancel method on a Future object. The argument true passed to cancel(true) means an attempt to interrupt the task, while false means attempting a graceful cancellation. Using stop() and interrupt() is not recommended for canceling tasks, and shutdown() is used to shut down the entire ExecutorService, not to cancel a specific task.

In Java, the String class creates an immutable sequence of characters. This means that once a string is created, its content cannot be changed. The other options, StringBuilder, StringBuffer, and CharArray, are used for mutable character sequences.

A private constructor is commonly used in the Singleton design pattern. The Singleton pattern ensures that a class has only one instance, and the private constructor prevents external instantiation. It is not typically used for inheritance, polymorphism, or abstraction.

In Java, a two-dimensional array int[][] arr is essentially an array of arrays. It means that each element of arr is itself an array, which can hold integers or other data types. This concept allows you to create tables or matrices of data.

In Java, the static block is executed before constructors. Static blocks are used for performing class-level initialization tasks. They run when the class is loaded, and they are executed only once. Constructors, on the other hand, are used to initialize instance variables and are called when an object is created.

The flatMap() method in the Stream API is used to flatten a stream of streams into a single stream. It is particularly useful when you have a stream of elements, and each element is itself a stream (e.g., a stream of lists). flatMap() will merge all these sub-streams into one, providing a single stream of elements. This is different from map(), which produces a stream of streams.

DriverManager is not a part of the JDBC API. It is a class in the Java standard library used to manage a list of database drivers. The other options are part of the JDBC API for working with databases in Java.

In Java, if a method in an interface is declared without an access modifier, it is implicitly considered public. This means that the method is accessible from any class that implements the interface, even if it is in a different package. The other access modifiers (private, protected, and package-private) cannot be used for interface methods.

The average-case time complexity of Binary Search is O(log n), where 'n' is the number of elements in the array. This is because, on average, Binary Search eliminates half of the remaining elements with each comparison, resulting in a logarithmic growth rate. In the worst-case, it is still O(log n), but in the best-case, it can be O(1) as mentioned in the first question.

In Java, the ^ operator is the bitwise XOR operator. It performs a bitwise XOR operation on the binary representations of the two operands. In this case, 7 in binary is 0111, and 3 in binary is 0011. Performing XOR, we get 0100, which is 4 in decimal. So, the result is 4.