Java Constant Definition: The final Keyword and Constants, Avoiding Reassignment

In Java, a constant is a value that cannot be modified after assignment, commonly defined using the `final` keyword. The syntax is `final dataType constantName = initialValue`; it must be initialized upon declaration and cannot be modified repeatedly after assignment. Constants have significant roles: preventing accidental modifications (compiler errors), enhancing readability (naming convention with uppercase letters and underscores), and facilitating maintenance (changes take effect globally). Class constants are defined with `static final` (e.g., `AppConfig.DB_URL`) for sharing across multiple classes. It is important to note common pitfalls: the reference of a `final` object is immutable, but its attributes can still be modified; the naming convention must be clear. Proper use of constants reduces bugs, improves code reliability, and is a core concept in Java's basic syntax.