Can you describe the concept of stream in Java Stream API and its main applications?

In Java Stream API, a stream is a sequence of elements that supports data processing operations such as filtering, transforming, and aggregating. Streams allow writing declarative code for working with collections and other data sources, facilitating parallel processing and improving readability.

Main areas of application:

• Processing collections (List, Set, etc.)
• Filtering, sorting, transforming data
• Performing aggregate operations (sum, average, count)
• Parallel data processing using parallel streams

Example:

List<String> names = Arrays.asList("Anna", "Bob", "Charlie");
List<String> filtered = names.stream()
    .filter(name -> name.startsWith("A"))
    .collect(Collectors.toList());