Connecting Java Streams - Quiz Explanation

The answers you selected are indicated below, along with text that explains the correct answers.

1.	Which of the following requires a separate stream object to provide raw data? Please select the best answer.
	A.	ByteArrayInputStream
	B.	DataInputStream
	C.	FileInputStream
	D.	System.in
	The correct answer is B. A DataInputStream only reinterprets the raw bytes of data provided by another, underlying stream such as System.in, a ByteArrayInputStream, or a FileInputStream.

2.	Which of the following cannot be chained to a FileOutputStream? Please select the best answer.
	A.	BufferedOutputStream
	B.	DataOutputStream
	C.	PrintStream
	D.	ByteArrayOutputStream
	The correct answer is D. ByteArrayOutputStream does not extend FilterOutputStream, so it cannot be chained to nonfilter streams. Semantically, a byte array is a destination like a file, not a filter or a buffer. If you were somehow able to chain a FileOutputStream to a ByteArrayOutputStream, the same data would end up in two different places.

3.	If you wanted a class that could write little-endian data, you would most likely extend: Please select the best answer.
	A.	FilterOutputStream
	B.	FilterInputStream
	C.	DataOutputStream
	D.	OutputStream
	The correct answer is A. FilterOutputStream. Since you will want to read data from an underlying source and modify it before passing it on, you need a filter stream. This is an output problem so Answer B is ruled out. You could extend OutputStream directly, but extending FilterOutputStream is easier since you don't have to implement write(). Furthermore, other programmers who use this class will find it easier to understand. Similarly, you could extend DataOutputStream, but you don't need the extra methods of the DataOutputStream class. It's best to use FilterOutputStream for what it was meant for, exactly this sort of problem.