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

Core Java - Interview Questions and Answers for 'Scanner' - 6 question(s) found - Order By Newest

Q1. What is Scanner class used for ? when was it introduced in Java ?

Ans. Scanner class introduced in Java 1.5 for reading Data Stream from the imput device. Previously we used to write code to read a input using DataInputStream. After reading the stream , we can convert into respective data type using in.next() as String ,in.nextInt() as integer, in.nextDouble() as Double etc

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Q2. Write code explaining use of Scanner class ?

Ans. Scanner sc = new Scanner(System.in);
int i = sc.nextInt();

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Q3. 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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Q4. Write a program / method to input few numbers and then print the sum.

Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?&category=code&searchOption&keyword=946

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Q5. 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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Q6. 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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