SWE211 Java I/O Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What mode allows both reading and writing when creating a RandomAccessFile object?

rw (correct)

In the RandomAccessFile, which number corresponds to the initial position of the file?

555

0 (correct)

If the current file length is 800 and new data increases the length to 804, how many bytes were added?

4 (correct)

Which method can be implemented to check if a specific line exists in a file using RandomAccessFile?

readLine() Signup and view all the answers

What is the purpose of the file pointer in a random access file?

To indicate where the next read or write operation occurs. Signup and view all the answers

What happens to the file pointer when data is read from a random access file?

It moves forward to the next data location. Signup and view all the answers

What is the primary purpose of a RandomAccessFile?

To allow random access for reading and writing Signup and view all the answers

How many bytes are referenced by the line representing the eleventh number in the RandomAccessFile?

555 Signup and view all the answers

Which method in RandomAccessFile is used to set the file pointer to a specific position?

seek(long pos) Signup and view all the answers

Which statement about the method writeChars(String s) is true?

It writes a string as a sequence of characters. Signup and view all the answers

Which mode would you use to create a RandomAccessFile for read-only access?

r Signup and view all the answers

What feature is provided by the RandomAccessFile to count the occurrence of a word in a file?

checkWordExists() Signup and view all the answers

How is the length of a random access file obtained?

By calling the length() method. Signup and view all the answers

What does the method getFilePointer() return?

The current offset from the beginning of the file. Signup and view all the answers

Which of the following methods can also be found in DataInputStream and DataOutputStream?

writeInt() Signup and view all the answers

When the RandomAccessFile is opened, where is the file pointer initially positioned?

At the beginning of the file. Signup and view all the answers

What is a key characteristic of data stored in binary files?

It is designed for programs to read and process efficiently. Signup and view all the answers

How does a text file represent the decimal integer 199?

As a sequence of characters '1', '9', '9'. Signup and view all the answers

What is the primary advantage of binary files over text files?

They offer more efficient processing. Signup and view all the answers

What encapsulates the properties of a file or a path in Java?

File Signup and view all the answers

Which of the following statements about binary files is correct?

They contain data in a format primarily for machine processing. Signup and view all the answers

What do you need to create in order to perform I/O operations in Java?

Objects from appropriate Java I/O classes. Signup and view all the answers

What does a File object in Java NOT contain?

Methods for reading and writing data Signup and view all the answers

When saving the integer 199 in a binary file, what form does it take?

As a byte-type value C7. Signup and view all the answers

Study Notes

Object-Oriented Programming (SWE211) - Java I/O

I/O Handling in Java: A File object stores file properties but not I/O methods. To read/write, use Java I/O classes (e.g., Scanner, PrintWriter).
Text File vs. Binary File: Text files store data in human-readable form (e.g., "199"). Binary files store data in binary form (e.g., 'C7'). Binary files are more efficient to process. Text files are readable by text editors.
Binary I/O Classes: Java provides classes (FileInputStream, DataInputStream, FileOutputStream, DataOutputStream) for efficient binary I/O. The hierarchy includes InputStream, OutputStream, FilterInputStream, FilterOutputStream, and BufferedInputStream, BufferedOutputStream.
Input Streams (java.io.InputStream):
- read(): Reads a byte as an integer (0-255); returns -1 at end of stream.
- read(byte[] b): Reads up to b.length bytes; returns actual count or -1.
- read(byte[] b, int off, int len): Reads bytes into b[off] to b[off+len-1]; returns number read or -1 at end.
- available(): Returns number of bytes readable.
- close(): Releases resources associated with the stream.
- skip(long n): Skips n bytes of data(discards).
Output Streams (java.io.OutputStream):
- write(int b): Writes a byte (integer representation).
- write(byte[] b): Writes the entire byte array.
- write(byte[] b, int off, int len): Writes b[off] to b[off+len-1].
- close(): Releases resources.
- flush(): Writes buffered bytes to the stream.
FileInputStream/FileOutputStream: Connects to a file as an input or output stream.
FileInputStream Constructors: FileInputStream(String filename), FileInputStream(File file).
FileOutputStream Constructors: FileOutputStream(String filename), FileOutputStream(File file), FileOutputStream(String filename, boolean append), FileOutputStream(File file, boolean append).
DataInputStream: Reads primitive data types (e.g., integers, characters) from a byte stream
DataOutputStream: Writes primitive data types (e.g., integers, characters) to a byte stream
ObjectInputStream/ObjectOutputStream: Handle object serialization to files.
Serializable Interface: Classes that implement this interface allow Java to serialize object instances.
BufferedInputStream, BufferedOutputStream: Use buffers to improve I/O performance.
RandomAccessFile: Enables random access read/write operations to files.
File Pointer: A marker indicating the current location in a file during read/write operations in RandomAccessFile.
RandomAccessFile Methods: seek, getFilePointer, length.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on Java I/O handling in the course SWE211. This quiz covers topics such as text and binary file processing, input/output classes, and stream management in Java. Perfect for students looking to solidify their understanding of I/O operations.