Java Comp274
1. What is the Java source filename extension? What is the Java bytecode filename extension?

Source file should use a .java extension and a bytecode should use a .class extension.

2. Write a Java statement to display the string “The value is 100” to a user in a plain dialog box.

import javax.swing.JOptionPane;

public class ValueMessage
{
public static void main (String[] args) { JOptionPane.showMessageDialog(null, “The value is 100”); }
}

3. What is the command you would use to compile the file Addition.java?

Javac

4. What is the command you would use to execute the Addition class?

Java

5. What does a Java class contain that identifies it as a Java application?

A main method.

public static void main(String args[])

6. Write a Java statement that declares a constant called MAX which has a value of 1000.

Final int MAX = 1000

7. How do C++ chars differ from Java chars?

The char in C++ is an 8-bit type that uses the ASCII character set while Java is a 16-bit type that uses the Unicode character set.

8. Given a double variable called dval, write a single Java statement to prompt the user to enter the price of an item using JOptionPanes, convert the result and store it into dval.

dval = Double.parseDouble(JOptionPane.showInputDialog(null, "Enter a Price"));

9. Write one Java statement to display the string “The average is xxx” to the console, where the xxx displays the value from the double variable sum divided by 3. Make sure the value is displayed with 3 digits following the decimal point.

System.out.printf("The average is %.3f\n", sum/3);

10. Write one Java statement to create a string containing “The average is xxx” where the xxx contains the formatted value from the double variable sum divided by 3. Make sure the formatted string contains only 2 digits following the decimal point. Store the formatted string into a