Answer Posted / ramana

override methos have same method name with same
signature.which methods are apper in super class to sub
class.

what happens when a thread cannot acquire a lock on an object? : Java thread

1014

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What is the difference between int and integer in java?

985

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what are the states associated in the thread? : Java thread

1001

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How can I right-justify a string?

1100

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Can we assign integer value to char in java?

963

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What is wrapper class example?

935

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Why main() method is public, static and void in java ?

1032

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What is parsing in java?

904

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what is thread? : Java thread

935

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I don’t want my class to be inherited by any other class. What should I do?

967

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What is a parameter used for?

916

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Which is the best approach for creating thread ?

1138

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What is this keyword used for?

1067

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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)

1878

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Is string a datatype?

931

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