Question

1.

What does the following code print to the console?
LocalDate date = LocalDate.of(1976, Month.JANUARY, 1);
DateTimeFormatter dtf = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM);
System.out.println(dtf.format(date));

	a.	01/01/1976
	b.	Jan 1, 1976
	c.	1976-01-01
	d.	01/01/76

2.

What is the value of s2 after the code that follows is executed?
String s1 = "118-45-9271";
String s2 = "";
for (int i = 0; i < s1.length(); i++) {
    if (s1.charAt(i) != '-') {
        s2 += s1.charAt(i);
    }
}
s2 = s2.replace('-', '.');

	a.	118.45.9271
	b.	118-45-9271
	c.	118 45 9271
	d.	118459271

3.

What is the minimum modification needed to make the code that follows compile?
public void readData() {
    boolean dataNotFound = true;
    if (dataNotFound) {
        throw new IOException();
    }
    catch(IOException e) {
        System.out.println("data file can't be found");
    }
}

	a.	Place the if statement within a try block.
	b.	Add a throws clause to the method declaration.
	c.	Set dataNotFound to false.
	d.	No modification is needed

4.

How many streams are used in the following statement?
DataInputStream in = new DataInputStream(
                     new BufferedInputStream(
                     new FileInputStream(file)));

	a.	3
	b.	2
	c.	1
	d.	4

5.

If the getBalance() method in the BankDB class throws an IOException and the BalanceException class is derived from the Exception class, which of the following is a valid method declaration for a method that contains only this code?
balance = BankDB.getBalance(accountNumber);
if (balance < 0) {
    throw new BalanceException("Negative balance");
}

	a.	public void processTransaction() throws IOException{...}
	b.	public void processTransaction() throws BalanceException{...}
	c.	public void processTransaction() throws IOException, BalanceException{...}
	d.	public void processTransaction(){...}

Answer 1

1] Format style enum has four constants SHORT, MEDIUM, FULL, LONG. They are used to format date and time in different length. Predefined style for MEDIUM DateTimeFormatter is : month day, year.

b] jan 1, 1976

  

 import java.util.*; import java.lang.*; import java.io.*; import java.time.*; import java.time.format.DateTimeFormatter; import java.time.format.FormatStyle; class DateFormat {     public static void main (String[] args) throws java.lang.Exception      {               LocalDate date = LocalDate.of(1976, Month.JANUARY, 1); DateTimeFormatter dtf = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM); System.out.println(dtf.format(date));     } }

Output Jan 1, 1976

2] s1 = "118-45-9271"

s1.length() = 11

Loop : 1st iteration

for i =0 if (s1.charAt(0) != '-') (where s1.charAt(0) = '1' )    therefore we will enter into if block and s2 = '1'

2nd iteration

for i =1 if( s1.charAt(1) != '-') (where s1.charAt(1) = '1' )    therefore we will enter into if block and s2 = '11'

3rd iteration

for i =2 if( s1.charAt(2) != '-') (where s1.charAt(2) = '8' )    therefore we will enter into if block and s2 = '118'

4th iteration

for i =3 if(s1.charAt(1) != '-') (where s1.charAt(1) = '-' )    therefore we will not enter into if block and s2 = '118'

and so on, finally we will have s2 = 118459271

Statement s2 = s2.char.At('-' ,'.') means replace every '-' with '.' in string s2. But it won't have any effect as s2 doesn't contain character '-' .

OUTPUT : d] 118459271

 import java.util.*; import java.lang.*; import java.io.*; class Output {        public static void main (String[] args) throws java.lang.Exception      {               String s1 = "118-45-9271"; String s2 = ""; for (int i = 0; i < s1.length(); i++) { if (s1.charAt(i) != '-') { s2 += s1.charAt(i); } } s2 = s2.replace('-', '.'); System.out.println(s2); } } 

Output 118459271

3] Option a) Place the if statement within a try block.

In the given code snippet we can clearly see a Catch block. Catch block must only be used after a try block. Multiple catch blocks can be used with a single try block.

Try block is used to enclose a part of code which might throw exception and the exception is catched by a catch block.

When an exception occurs JVM checks if the exception is handled. Try-Catch blocks are used to handle exception.

4] Answer should be 3

import java.io.BufferedInputStream

import java.io.DataInputStream

import java.io.FileInputStream