Mastering Java: The Ultimate Quiz for 'Thinking in Java'

Which operation can be used for both string concatenation and arithmetic addition in Java?

1. +

2. *

3. -

4. +=

The correct answer is: +

In Java, the + operator can be used for both string concatenation and arithmetic addition. This operator is most commonly associated with addition, but it can also be used to concatenate strings. The * and - operators are used for multiplication and subtraction, respectively. The += operator is a compound assignment operator, which combines addition and assignment. It is not used for string concatenation. Therefore, the correct answer would be A.