The intern() method of the String class is used to add the String to the string pool if it's not already there and returns a reference to that String. This can reduce memory usage by ensuring only one copy of a particular string exists in the string pool, which is useful for memory optimization. The intern() method has been available since early versions of Java, not just in Java 9 and later.

In Java, the shutdown() method of ExecutorService attempts to stop all actively executing tasks and halts the processing of waiting tasks. It's a graceful way to shut down an executor, allowing it to finish executing tasks before terminating. It is essential to manage thread pools effectively in concurrent applications.

Using SocketChannel in non-blocking mode (option a) can lead to improved performance with lower CPU usage compared to traditional blocking I/O sockets. Non-blocking SocketChannels can handle multiple connections concurrently. Option c is incorrect because non-blocking SocketChannels are often favored for high-throughput scenarios. Option d is not accurate as data integrity is not directly related to blocking or non-blocking mode.

A Callable in Java is a result-bearing computation that can be canceled and can compute the result asynchronously. It is typically used with ExecutorService to perform tasks that return values or throw exceptions.

To securely serialize and deserialize objects to protect sensitive information, you should use encryption techniques. Encrypting the data before serialization and decrypting it after deserialization ensures that the data remains confidential. While access modifiers and marking classes as final provide some level of security, they don't directly address the need for encryption. Custom logic with encryption and authentication is a comprehensive approach to security.

You can use the conditional (ternary) operator ? : to achieve this. If the condition is true, it negates the numericValue by using the unary minus operator. If false, it leaves the numericValue unchanged. Option 1 demonstrates this technique.

The ObjectOutputStream class in Java is used to serialize objects into a byte stream. It's responsible for writing the state of an object to the output stream. Conversely, ObjectInputStream is used for reading serialized objects from a stream. It is an essential part of Java's serialization mechanism.

When you try to execute a DML operation (such as INSERT, UPDATE, DELETE) using the executeQuery() method, option b is correct. It will throw a SQLException because executeQuery() is meant for querying data and returns a ResultSet, which is not applicable to DML operations. Options a and c are incorrect because they suggest that the DML operation can proceed, which is not the case. Option d is also incorrect; it does not represent the actual behavior of executeQuery().

In JavaFX, long-running tasks like database operations should be executed on background threads to avoid freezing the UI. The recommended approach is to use the Task class and Platform.runLater() to safely update the UI from background threads. The other options are not suitable for ensuring UI responsiveness during long tasks.

Yes, Java allows interfaces to contain static methods, introduced in Java 8. Static methods in interfaces can be called without creating an instance of the interface and are often used for utility functions or factory methods.

Deadlocks occur when two or more threads are blocked, each waiting for a resource that the other holds. To resolve deadlocks involving synchronized methods or blocks, one approach is to use fewer threads or to minimize the usage of synchronized sections to reduce the chances of threads waiting indefinitely, thereby avoiding ________.

The reference data type Character is used for storing a single character in Java. It is different from the primitive data type char, which also stores a single character but is not a reference data type. String is used to store sequences of characters, and Integer is for integer values.