Java SE 8 Programmer

The code demonstrates the difference between passing objects and primitive values in Java. In Java, objects (like 'Product' here) are passed by reference, meaning changes to the object's properties remain after the method call. On the other hand, primitive data types (like 'double' here) are passed by value, meaning changes to the variable inside the method do not affect the original value. Within the 'updatePrice' method, 'price' is a local variable and multiplying it by 2 doesn't affect the original 'newPrice' value. However, 'product.price' is updated through its reference. Initially, 'product.price' is 200. After calling 'updatePrice', 'product.price'+price' becomes 200+200 = 400. Therefore, the output is 'product.price: 400.0' and 'newPrice: 100.0', resulting in '400.0 : 100.0'.

The break statement at the end of each case block in a switch statement is optional. However, if it is omitted, the program will continue to execute the subsequent cases until a break statement is encountered or the switch ends. This feature is often used intentionally in fall-through scenarios, but if not used carefully, it can lead to unintended behavior.

The code will throw an exception at runtime. The LocalDate class represents a date without time, while the ISO_DATE_TIME formatter expects both date and time components. Since the parsed LocalDate object does not contain time information, attempting to format it with DateTimeFormatter.ISO_DATE_TIME will result in an UnsupportedTemporalTypeException because it will look for time fields such as HourOfDay which are missing.

Compilation fails at line n2 due to an invalid cast. The code attempts to cast a long to a String, which is not permissible in Java. In detail, objects of primitives type like `long` cannot be directly cast to a non-primitive type like `String`. A suitable approach would be to use `String.valueOf()` method or concatenation with an empty string to convert the result into a String.

The Java concept that uses access modifiers to protect variables and hide them within a class is called encapsulation. Encapsulation involves using access modifiers like private to restrict access to the class's fields, ensuring that the data can only be accessed or modified through public methods, known as getters and setters. This protects the integrity of the data and hides the internal workings of the class from outside interference.