Podcast
Questions and Answers
What mode allows both reading and writing when creating a RandomAccessFile object?
What mode allows both reading and writing when creating a RandomAccessFile object?
- r+
- w
- r
- rw (correct)
In the RandomAccessFile, which number corresponds to the initial position of the file?
In the RandomAccessFile, which number corresponds to the initial position of the file?
- 1
- 9
- 555
- 0 (correct)
If the current file length is 800 and new data increases the length to 804, how many bytes were added?
If the current file length is 800 and new data increases the length to 804, how many bytes were added?
- 8
- 4 (correct)
- 6
- 2
Which method can be implemented to check if a specific line exists in a file using RandomAccessFile?
Which method can be implemented to check if a specific line exists in a file using RandomAccessFile?
What is the purpose of the file pointer in a random access file?
What is the purpose of the file pointer in a random access file?
What happens to the file pointer when data is read from a random access file?
What happens to the file pointer when data is read from a random access file?
What is the primary purpose of a RandomAccessFile?
What is the primary purpose of a RandomAccessFile?
How many bytes are referenced by the line representing the eleventh number in the RandomAccessFile?
How many bytes are referenced by the line representing the eleventh number in the RandomAccessFile?
Which method in RandomAccessFile is used to set the file pointer to a specific position?
Which method in RandomAccessFile is used to set the file pointer to a specific position?
Which statement about the method writeChars(String s) is true?
Which statement about the method writeChars(String s) is true?
Which mode would you use to create a RandomAccessFile for read-only access?
Which mode would you use to create a RandomAccessFile for read-only access?
What feature is provided by the RandomAccessFile to count the occurrence of a word in a file?
What feature is provided by the RandomAccessFile to count the occurrence of a word in a file?
How is the length of a random access file obtained?
How is the length of a random access file obtained?
What does the method getFilePointer() return?
What does the method getFilePointer() return?
Which of the following methods can also be found in DataInputStream and DataOutputStream?
Which of the following methods can also be found in DataInputStream and DataOutputStream?
When the RandomAccessFile is opened, where is the file pointer initially positioned?
When the RandomAccessFile is opened, where is the file pointer initially positioned?
What is a key characteristic of data stored in binary files?
What is a key characteristic of data stored in binary files?
How does a text file represent the decimal integer 199?
How does a text file represent the decimal integer 199?
What is the primary advantage of binary files over text files?
What is the primary advantage of binary files over text files?
What encapsulates the properties of a file or a path in Java?
What encapsulates the properties of a file or a path in Java?
Which of the following statements about binary files is correct?
Which of the following statements about binary files is correct?
What do you need to create in order to perform I/O operations in Java?
What do you need to create in order to perform I/O operations in Java?
What does a File object in Java NOT contain?
What does a File object in Java NOT contain?
When saving the integer 199 in a binary file, what form does it take?
When saving the integer 199 in a binary file, what form does it take?
Flashcards
File Pointer
File Pointer
A special marker within a random access file that indicates the current reading or writing position.
Random Access File
Random Access File
A file that allows data to be accessed in any order, regardless of its physical location within the file.
seek(long pos)
seek(long pos)
A method that moves the file pointer to a specified position within a RandomAccessFile.
getFilePointer()
getFilePointer()
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length()
length()
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writeChar(int v)
writeChar(int v)
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writeChars(String s)
writeChars(String s)
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RandomAccessFile
RandomAccessFile
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What is a Random Access File?
What is a Random Access File?
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What is the purpose of RandomAccessFile raf = new RandomAccessFile("test.dat", "rw");
?
What is the purpose of RandomAccessFile raf = new RandomAccessFile("test.dat", "rw");
?
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What is the purpose of RandomAccessFile raf = new RandomAccessFile("test.dat", "r");
?
What is the purpose of RandomAccessFile raf = new RandomAccessFile("test.dat", "r");
?
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How does the file pointer work in a RandomAccessFile?
How does the file pointer work in a RandomAccessFile?
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What is the purpose of the seek(long pos)
method?
What is the purpose of the seek(long pos)
method?
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What purpose does the getFilePointer()
method serve?
What purpose does the getFilePointer()
method serve?
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What is the purpose of the length()
method?
What is the purpose of the length()
method?
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How does the writeChar(int v)
method work?
How does the writeChar(int v)
method work?
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Scanner Class
Scanner Class
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PrintWriter Class
PrintWriter Class
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Text Files
Text Files
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Binary Files
Binary Files
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Input
Input
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Output
Output
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Input/Output Stream
Input/Output Stream
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File Object
File Object
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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 includesInputStream
,OutputStream
,FilterInputStream
,FilterOutputStream
, andBufferedInputStream
,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 tob.length
bytes; returns actual count or -1.read(byte[] b, int off, int len)
: Reads bytes intob[off]
tob[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)
: Skipsn
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)
: Writesb[off]
tob[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
.
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