What are lambda expressions in Java?

Lambda expressions in Java are a key feature introduced in Java 8 that provide a concise way to represent anonymous methods or functions. In essence, they allow for the implementation of functional interfaces in a more readable and shorter syntax, enabling developers to write cleaner and more expressive code for tasks such as passing behavior as arguments to methods, filtering collections, and more.

The main advantage of lambda expressions is that they simplify the process of using functional programming paradigms in Java. For example, instead of writing a full class or anonymous inner class to implement a single method of an interface, you can now use a lambda expression to succinctly express the behavior. This contributes to less boilerplate code, improved readability, and ease of maintenance.

Using lambda expressions also enables better utilization of the Streams API and other functional-style programming constructs in Java, making operations like filtering and mapping collections both efficient and straightforward.

The other options describe concepts that do not accurately represent the purpose or functionality of lambda expressions in Java. For instance, they are unrelated to databases, debugging, or accusations of adding complexity—rather, they are intended to reduce complexity and enhance the flexibility and clarity of code.