Answer Posted / deepak divvela

String hostname=Inetaddress.getAddress("portno of tcs
mail").getHostName();

Difference between error and exception

6008

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What is string in java is it a data type?

1002

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Does a class inherit the constructors of its superclass in java programming?

1082

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The following program reads data (details of students) from a file named students.txt and converts it into e-mail addresses. The results are written to a file named studentemail.txt. students.txt consists of a number of lines, each containing the data of a student in colon delimited format: Last Name:First Name:Student Number Each input record is converted to an e-mail address and written to studentemail.txt in the following format: the first character of the last name + the first character of the first name + the last four digits of the student number + “@myunisa.ac.za” import java.io.*; public class EmailConverter { public static void main(String[] args) throws IOException { BufferedReader input = new BufferedReader(new FileReader ("students.txt")); PrintWriter output = new PrintWriter(new FileWriter ("studentemail.txt")); String line = input.readLine(); while (line != null) { // Extract the information for each student String[] items = line.split(":"); // Generate the email address String email = "" + items[0].charAt(0) + items[1].charAt(0) + items[2].substring(4,8) + "@myunisa.ac.za"; email = email.toLowerCase(); // Output output.println(email); line = input.readLine(); } input.close(); output.close(); } } Rewrite the class so that it handles possible errors that may occur. In particular, it should do the following: • It should catch at least three appropriate exceptions that might occur, and display suitable messages. • At this stage, the program will not run correctly if there is an empty line in the input file. Change the program so that if an empty line is encountered, an exception is thrown and the empty line is ignored. This exception should be handled with the display of a suitable error message. • Before the e-mail address is added to the output file, check if the student number has 8 digits. If not, throw an InvalidFormatException (which the program should not handle itself)

1927

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Does java linked list allow duplicates?

952

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Write a java program for binary search?

1036

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Why java is considered dynamic?

1148

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What are the six ways to use this keyword?

1046

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How do you check if two given string are anagrams?

945

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How do I convert a numeric ip address like 192.18.97.39 into a hostname like java.sun.com?

998

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Is hashset ordered?

1040

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What are constants?

1037

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Why java doesn’t support multiple inheritances?

1012

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How can we create an immutable class in java?

1053

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What does it mean that a method or field is “static”?

960

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