Java IO Streams Interview Questions and Answers
- What is an IO stream?
It is a stream of data that flows from source to destination. A good example is file copying. Two streams are involved – input stream and output stream. An input stream reads from the file and stores the data in the process (generally in a temporary variable). The output stream reads from the process and writes to the destination file.
- What is the necessity of two types of streams – byte streams and character streams?
Byte streams were introduced with JDK 1.0 and operate on the files containing ASCII characters. We know Java supports other language characters also known as Unicode characters. To read the files containing Unicode characters, the designers introduced character streams with JDK 1.1. As ASCII is a subset of Unicode, for the files of English characters, we can go with either byte streams or character streams.
- What are the super most classes of all streams?
All the byte stream classes can be divided into two categories (input stream classes and output stream classes) and all character streams classes into two (reader classes and writer classes). There are four abstract classes from which all these streams are derived. The super most class of all byte stream classes is java.io.InputStream and for all output stream classes, java.io.OutputStream. Similarly for all reader classes is java.io.Reader and for all writer classes are java.io.Writer.
- What are FileInputStream and FileOutputStream?
These two are general purpose classes used by the programmer very often to copy the file to file. These classes work well with files containing fewer data of a few thousand bytes as by performance these are very poor. For larger data, it is preferred to use BufferedInputStream (or BufferedReader) and BufferedOutputStream (or BufferedWriter).
- Which you feel better to use – byte streams or character streams?
I feel personal to go with character streams as they are the latest. Many features exist in character streams that do not in byte streams like a) using BufferedReader in place of BufferedInputStreams and DataInputStream (one stream for two) and b) using newLine()method to go for next line and for this effect we must go for extra coding in byte streams etc.
- What System.out.println()?
"println()" is a method of PrintStream class. "out" is a static object of PrintStream class defined in "System" class. The system is a class from java.lang package used to interact with the underlying operating system by the program.
- What are the filter streams?
Filter streams are a category of IO streams whose responsibility is to add extra functionality (advantage) to the existing streams like giving line numbers in the destination file that do not exist in the source file or increasing performance of copying etc.
- Name the filter streams available?
There are four filter streams in the java.io package – two on the byte streams side and two in the character streams side. They are FilterInputStream, FilterOutputStream, FilterReader and FilterWriter. These classes are abstract classes and you cannot create objects of these classes.
- Name the filter stream classes on the reading side of byte stream?
There are four classes – LineNumberInputStream (the extra functionality is it adds line numbers in the destination file), DataInputStream (contains special methods like readInt(), readDouble() and readLine() etc that can read an int, a double and a string at a time), BufferedInputStream (gives buffering effect that increases the performance to the peak) and PushbackInputStream (pushes the required character back to the system). - .Java IO Streams Interview Questions and Answers
- What is the functionality of SequenceInputStream?
It is very useful to copy multiple source files into one destination file with very less code.
- What are PrintStream and PrintWriter?
Functionally both are the same but belong to two different categories – byte streams and character streams. println() method exists in both classes.
- Which streams are advised to use to have maximum performance in file copying?
BufferedInputStream and BufferedOutputStream on byte streams side and BufferedReader and BufferedWriter on character streams side.
- What are piped streams?
There are four piped streams – PipedInputStream, PipedOutputStream, PipedReader, and PipedWriter. These streams are very useful to pass data between two running threads (say, processes). Java IO Interview Questions and Answers
- What is File class?
It is a non-stream (not used for file operations) class used to know the properties of a file like when it was created (or modified), has read and write permissions, size, etc.
- What is RandomAccessFile?
It is a special class from the java.io package which is neither an input stream nor an output stream (because it can do both). It is directly a subclass of Object class. Generally, a stream does only one purpose of either reading or writing: but RandomAccessFile can do both readings from a file and writing to a file. All the methods of DataInputStream and DataOutStream exist in RandomAccessFile.
refer sites:
web2.0:
tech-we-in.blogspot.comIt is a stream of data that flows from source to destination. A good example is file copying. Two streams are involved – input stream and output stream. An input stream reads from the file and stores the data in the process (generally in a temporary variable). The output stream reads from the process and writes to the destination file.
Byte streams were introduced with JDK 1.0 and operate on the files containing ASCII characters. We know Java supports other language characters also known as Unicode characters. To read the files containing Unicode characters, the designers introduced character streams with JDK 1.1. As ASCII is a subset of Unicode, for the files of English characters, we can go with either byte streams or character streams.
All the byte stream classes can be divided into two categories (input stream classes and output stream classes) and all character streams classes into two (reader classes and writer classes). There are four abstract classes from which all these streams are derived. The super most class of all byte stream classes is java.io.InputStream and for all output stream classes, java.io.OutputStream. Similarly for all reader classes is java.io.Reader and for all writer classes are java.io.Writer.
These two are general purpose classes used by the programmer very often to copy the file to file. These classes work well with files containing fewer data of a few thousand bytes as by performance these are very poor. For larger data, it is preferred to use BufferedInputStream (or BufferedReader) and BufferedOutputStream (or BufferedWriter).
I feel personal to go with character streams as they are the latest. Many features exist in character streams that do not in byte streams like a) using BufferedReader in place of BufferedInputStreams and DataInputStream (one stream for two) and b) using newLine()method to go for next line and for this effect we must go for extra coding in byte streams etc.
"println()" is a method of PrintStream class. "out" is a static object of PrintStream class defined in "System" class. The system is a class from java.lang package used to interact with the underlying operating system by the program.
Filter streams are a category of IO streams whose responsibility is to add extra functionality (advantage) to the existing streams like giving line numbers in the destination file that do not exist in the source file or increasing performance of copying etc.
There are four filter streams in the java.io package – two on the byte streams side and two in the character streams side. They are FilterInputStream, FilterOutputStream, FilterReader and FilterWriter. These classes are abstract classes and you cannot create objects of these classes.
There are four classes – LineNumberInputStream (the extra functionality is it adds line numbers in the destination file), DataInputStream (contains special methods like readInt(), readDouble() and readLine() etc that can read an int, a double and a string at a time), BufferedInputStream (gives buffering effect that increases the performance to the peak) and PushbackInputStream (pushes the required character back to the system).
It is very useful to copy multiple source files into one destination file with very less code.
Functionally both are the same but belong to two different categories – byte streams and character streams. println() method exists in both classes.
BufferedInputStream and BufferedOutputStream on byte streams side and BufferedReader and BufferedWriter on character streams side.
There are four piped streams – PipedInputStream, PipedOutputStream, PipedReader, and PipedWriter. These streams are very useful to pass data between two running threads (say, processes). Java IO Interview Questions and Answers
It is a non-stream (not used for file operations) class used to know the properties of a file like when it was created (or modified), has read and write permissions, size, etc.
It is a special class from the java.io package which is neither an input stream nor an output stream (because it can do both). It is directly a subclass of Object class. Generally, a stream does only one purpose of either reading or writing: but RandomAccessFile can do both readings from a file and writing to a file. All the methods of DataInputStream and DataOutStream exist in RandomAccessFile.
javatutorialtuto.blogspot.com
techworld1207.blogspot.com
tutuappus.blogspot.com
tcswebmailus.blogspot.com
bookzzus.blogspot.com
jntu-worldin.blogspot.com
sankranthi123.blogspot.com
numberusa.blogspot.com
wrestlemaniaus.blogspot.com
gadgetsus.blogspot.com
banknumberus.blogspot.com
techweb-in.blogspot.com
techupdates-us.blogspot.com
techgadgets-us.blogspot.com
world-lienews-us.blogspot.com
education-indianews.blogspot.com
studyus-now.blogspot.com
tiktok-us.blogspot.com
walmartone-login.blogspot.com
c-languagetutorials.blogspot.com
lite-blue.blogspot.com
usps-packagetracking.blogspot.com
ups-packagetracking.blogspot.com
fedex-tracking.blogspot.com
hotmail-loginguide.blogspot.com
pubg-litee.blogspot.com
bank-routingnumbers.blogspot.com
new-latestbikes.blogspot.com
tutorialswebonline.blogspot.com
nice post. www.tellpopeyes.com survey questions and answers
ReplyDelete