Answer Posted / md. abid hossain

In 3 ways..
1)Using a Static Factory Method
ABC.getInstance();
2)Using newInstance() method...
class A=(A)Class.forName("A").newInstance();
3)Using clone() method.

What does nextint () do in java?

1054

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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)

1988

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How do you remove spaces in java?

1081

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What kind of variables a class can consist of?

1156

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What are default methods ?

1107

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Why are functions called methods in java?

1044

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What is an object’s lock and which object’s have locks?

1011

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Can final class have constructor?

971

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what is optional in java 8?

1118

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Can we sort set in java?

1009

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Can you extend main method in java?

1254

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What is the purpose of static methods and static variables?

1125

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What are the differences between checked exception and unchecked exception?

1012

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What is the implementation of destroy method in java. Is it native or java code?

1019

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How to make a non daemon thread as daemon?

1112

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