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

Where do you use 'flip()' method?

1. Before writing data to a buffer

2. After writing data to a buffer and before reading

3. After reading data from a buffer

4. Before locking a buffer

The correct answer is: After writing data to a buffer and before reading

The 'flip()' method is typically used after writing data to a buffer and before reading from it. This is because 'flip()' resets the buffer's limit to the current position and sets the position to 0, allowing for the buffer to be read from. Using 'flip()' after writing ensures that the buffer is in the correct state to be read from. Option A, using 'flip()' before writing data to a buffer, would reset the position to 0 and overwrite any data that was already in the buffer. Option C, using 'flip()' after reading from a buffer, is incorrect because 'flip()' does not reset the position back to 0, which could lead to unexpected results when reading from the buffer again. Option D, using 'flip()' before locking a buffer, is also incorrect because 'flip()' is not related to locking and would not affect the functionality of locking