What does the following statement sequence print? final String str = "Java"; str += " is powerful"; System.out.println(str);

The code sequence provided actually does not result in a compile-time error. It correctly defines a final String variable str, assigns it the value "Java", then concatenates the string " is powerful" to it, and finally prints the resulting string.

To break it down, when the statement str += " is powerful"; is executed, it creates a new string that combines the existing value of str ("Java") with the new text (" is powerful"). Because strings in Java are immutable, the concatenation produces a new string ("Java is powerful") while leaving the original str unchanged.

Therefore, when System.out.println(str); is called, it prints "Java is powerful" to the console.

The correct result of the series of statements is that it prints "Java is powerful". The option that reflects this outcome is not pointed out in the answer provided, suggesting there may have been a misunderstanding regarding the behavior of final variables and string concatenation in Java.