Answer / v.raju

The Null interfaces are called as Marker interfaces or
tagged interfaces they doesnt contain any code , they will
just declared to give some information about the class,

For example Serializable is a marker interface , it states
that the class can be serializable


cheers,
varahala raju

What is the best definition for data?

0 Answers  

---

Can we restart a dead thread in java?

0 Answers  

---

i don't want fullforms of JDK an JVM i want definitions for them

2 Answers  

---

What do you mean by inner class in java?

0 Answers  

---

wht is mean by dirty read?

1 Answers  

---

What does t in java mean?

0 Answers  

---

Which is bigger double or float?

0 Answers  

---

What is the difference between preemptive scheduling and time slicing?

0 Answers  

---

Can we declare variables inside a method as Final Variables?

3 Answers  

---

How many types of parsers are there?

0 Answers  

---

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)

0 Answers  

---

Which is better arraylist or vector?

0 Answers  

---