JBG_HS_Ch10_SelfTest

JBG_HS_Ch10_SelfTest

SelfTest01

SelfTest Problem

Why does Java define both byte and character streams?

SelfTest Solution

The byte streams are the original streams defined by Java. They are especially useful for binary I/O, and they support random-access files. The character streams are optimized for Unicode.

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SelfTest02

SelfTest Problem

Even though console input and output is text-­based, why does Java still use byte streams for this purpose?

SelfTest Solution

The predefined streams, System.in, System.out, and System.err, were defined before Java added the character streams.

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SelfTest03

SelfTest Problem

Show how to open a file for reading bytes.

SelfTest Solution

Here is one way to open a file for byte input:

FileInputStream fin = new FileInputStream("test")

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SelfTest04

SelfTest Problem

Show how to open a file for reading characters.

SelfTest Solution

Here is one way to open a file for reading characters:

FileReader fr = new FileReader("test");

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SelfTest05

SelfTest Problem

Show how to open a file for random-­access I/O.

SelfTest Solution

Here is one way to open a file for random access:

randFile = new RandomAccessFile("test", "rw");

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SelfTest06

SelfTest Problem

How can you convert a numeric string such as "123.23" into its binary equivalent?

SelfTest Solution

To convert numeric strings into their binary equivalents, use the parsing methods defined by the type wrappers, such as Integer or Double.

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SelfTest07

SelfTest Problem

Write a program that copies a text file. In the process, have it convert all spaces into hyphens. Use the byte stream file classes. Use the traditional approach to closing a file by explicitly calling close().

SelfTest Solution

JBG_HS_Ch10_SelfTest07

$ java Hyphen file1.txt file2.txt 

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SelfTest08

SelfTest Problem

Rewrite the program described in question 7 so that it uses the character stream classes. This time, use the try­-with-­resources statement to automatically close the file.

SelfTest Solution

JBG_HS_Ch10_SelfTest08

$ java Hyphen file1.txt file2.txt

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SelfTest09

SelfTest Problem

What type of stream is System.in?

SelfTest Solution

InputStream

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SelfTest10

SelfTest Problem

What does the read() method of InputStream return when an attempt is made to read at the end of the stream?

SelfTest Solution

-1

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SelfTest11

SelfTest Problem

What type of stream is used to read binary data?

SelfTest Solution

DataInputStream

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SelfTest12

SelfTest Problem

Reader and Writer are at the top of the ____________ class hierarchies.

SelfTest Solution

Character-based I/O.

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SelfTest13

SelfTest Problem

The try­-with-­resources statement is used for ___________________________________.

SelfTest Solution

Automatic resource management.

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SelfTest14

SelfTest Problem

If you are using the traditional method of closing a file, then closing a file within a finally block is generally a good approach. True or False?

SelfTest Solution

True.

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SelfTest15

SelfTest Problem

Can local variable type inference be used when declaring the resource in a try­-with­-resources statement?

SelfTest Solution

Yes.

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