What mechanism in Java provides strict type control during compilation and program execution?

In Java, strict type control is ensured by the static typing system and the type checking mechanisms during compilation and runtime.

The main elements of this mechanism:

• Static typing: the types of variables and expressions are checked at compile time, preventing incompatible type assignments.
• Generics: allow creating type-safe collections and methods, reducing the need for type casting and eliminating runtime errors.
• Runtime type checking: for example, during casting, the JVM checks the correctness of the cast and throws a ClassCastException if an error occurs.

Example:

List<String> list = new ArrayList<>();
list.add("Hello");
// list.add(123); // Compilation error: cannot add Integer to List<String>

Object obj = "test";
String str = (String) obj; // correct cast
Integer num = (Integer) obj; // ClassCastException at runtime