The Java Map interface is a powerful data structure for handling key-value pairs. Present in the java.util package, it’s ideal for managing data associations where each key maps to a specific value. Common use cases include counting occurrences (e.g., word frequency in text), grouping data (e.g., products by category), or accessing items by specific identifiers (e.g., user IDs).

Strings are important concepts in programming and are data types that allow storage of character sequences. String methods are built-in functions that are called on a string to either get information or manipulate data. In Java, strings are treated as immutable data, therefore their values cannot be changed. To work with strings and perform operations on them, you need to understand string methods in Java and how they work.