Core Java - Interview Questions and Answers for 'Input output' | Search Interview Question

Core Java - Interview Questions and Answers for 'Input output' - 13 question(s) found - Order By Rating

Q1. Why do we need to close the Scanner ?

Core Java

Ans. For releasing input stream reference (System.in), you should close scanner.

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Q2. What is the difference between hasNextInt and nextInt method of scanner class ?

Core Java

Ans. The hasNextInt() is used to check if there are any more elements left and the nextInt() is used to access that element.

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Q3. Difference between System.out.printf and System.out.println ?

Core Java

Ans. println prints an additional end of line whereas printf doesnt.

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Q4. Explain System.out.println ?

Core Java

Ans. System is a class within java.lang package that contains several useful class fields and methods. It cannot be instantiated and hence can use only statically.even in this case this has been used statically i.e with class name itself and without creating an instance.

out is the static reference of Printstream declared as following in the System Class -

public final static PrintStream out = null;

println is the method of PrintStream class.

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Q5. What is System.in in Java ?

Core Java

Ans. It is an InputSream which is usually connected to the keyboard input of console program.

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Q6. What is the difference between System.console.write and System.out.println ?

Ans. System.console() returns null if your application is not run in a terminal (though you can handle this in your application)System.console() provides methods for reading password without echoing charactersSystem.out and System.err use the default platform encoding, while the Console class output methods use the console encoding

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Q7. Tell something about BufferedWriter ? What are flush() and close() used for ?

Ans. BufferedWriter is temporary source for data storage.BufferedWriter is used to write character data to the file.Flush() is method available in B.W which ensures that all data items are written to file including last character.Close() is used to closes the character output stream.

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Q8. Name few Buffered IO classes and interfaces ?

Ans. http://www.buggybread.com/2015/01/java-io-buffered-classes-and-interfaces.html

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Q9. Name few IO Stream classes and interfaces ?

Core Java

Ans. http://www.buggybread.com/2015/01/java-stream-io-classes-and-interfaces.html

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Q10. Name few Writer classes ?

Ans. http://www.buggybread.com/2015/01/java-output-writer-classes-and.html

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Q11. Name few Reader classes ?

Ans. http://www.buggybread.com/2015/01/java-input-reader-classes-and-interfaces.html

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Q12. Name few File IO related classes and interfaces ?

Core Java

Ans. http://www.buggybread.com/2015/01/java-file-io-classes-and-interfaces.html

Sample Code for File

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Q13. Difference between Scanner and BufferedReader ? Which one is faster and Why ?

Core Java

Ans. Scanner is used for parsing tokens from the contents of the stream while BufferedReader just reads the stream.

BufferedReader read files efficiently by using a buffer to avoid physical disk operations.

Buffer size of Scanner is usually smaller than the Buffered Writer.

BufferedReader is faster that Scanner as it just reads the Stream and doesn't Parse the tokens to read the stream into primitive data types.

Sample Code for Scanner

Sample Code for BufferedReader

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