Is it unsafe to call methods from a thread?

How do I call methods in my program? I need to fill methods in the areas with comments labeled?

• import java.util.Scanner; import java.lang.Math; public class LucVincentGeometry { public static void printMenu() { System.out.print("This is a geometry calculator. "); System.out.println("Choose what would you like to calculate: "); System.out.println("1. Find the area of a circle "); System.out.println("2. Find the area of a rectangle "); System.out.println("3. Find the area of a triangle "); System.out.println("4. Find the circumference of a circle "); System.out.println("5. Find the perimeter of a rectangle "); System.out.println("6. Find the perimeter of a triangle "); System.out.println("Enter the number of your choice "); } public static double circleArea( double radius ) { return Math.PI*radius*radius; } public static double rectangleArea( double length, double width ) { return length*width; } public static double triangleArea( double base, double height ) { return 0.5*base*height; } public static double circleCircumference( double radius ) { return 2*Math.PI*radius; } public static double rectanglePerimeter( double length, double width ) { return (2*length + 2*width); } public static double trianglePerimeter( double side1, double side2, double side3 ) { return side1 + side2 + side3; } public static void main (String [] args) { int choice; //the user's choice double value = 0; //the value returned from the method char letter; //the Y or N from the user's decision to exit double radius; //the radius of the circle double length; //the length of the rectangle double width; //the width of the rectangle double height; //the height of the triangle double base; //the base of the triangle double side1; //the first side of the triangle double side2; //the second side of the triangle double side3; //the third side of the triangle //create a scanner object to read from the keyboard Scanner keyboard = new Scanner (System.in); //do loop was chosen to allow the menu to be displayed first do { System.out.println(); //call the printMenu method printMenu(); choice = keyboard.nextInt(); switch (choice) { case 1: System.out.print("Enter the radius of the circle: "); radius = keyboard.nextDouble(); //call the circleArea method and store the result in the value variable System.out.println("The area of the circle is " + value); break; case 2: System.out.print("Enter the length of the rectangle: "); length = keyboard.nextDouble(); System.out.print("Enter the width of the rectangle: "); width = keyboard.nextDouble(); //call the rectangleArea method and store the result in the value variable System.out.println("The area of the rectangle is " + value); break; case 3: System.out.print("Enter the height of the triangle: "); height = keyboard.nextDouble(); System.out.print("Enter the base of the triangle: "); base = keyboard.nextDouble(); //call the triangleArea method and store the result in the value variable System.out.println("The area of the triangle is " + value); break; case 4: System.out.print("Enter the radius of the circle: "); radius = keyboard.nextDouble(); //call the circumference method and store the result in the value variable System.out.println("The circumference of the circle is " + value); break; case 5: System.out.print("Enter the length of the rectangle: "); length = keyboard.nextDouble(); System.out.print("Enter the width of the rectangle: "); width = keyboard.nextDouble(); //call the perimeter method and store the result in the value variable System.out.println("The perimeter of the rectangle is " + value); break; case 6: System.out.print("Enter the length of side 1 of the triangle: "); side1 = keyboard.nextDouble(); System.out.print("Enter the length of side 2 of the triangle: "); side2 = keyboard.nextDouble(); System.out.print("Enter the length of side 3 of the triangle: "); side3 = keyboard.nextDouble(); //call the perimeter method and store the result in the value variable System.out.println("The perimeter of the triangle is " + value); break; default: System.out.println("You did not enter a valid choice."); } keyboard.nextLine(); //consumes the new line character after the number System.out.println("Do you want to exit the program (Y/N)?: "); String answer = keyboard.nextLine(); letter = answer.charAt(0); }while (letter != &#3

• Answer:

  A method is declared using syntax that resembles the following form: [modifiers] [name]([type 1] [argument 1],[type 2] [argument 2][etc]) { [code block] } Given that declaration, you call the method inside any code block by using syntax resembling the following form: name([expression of type 1],[expression of type 2][etc]) If the method call stands alone, it must also be terminated by a semicolon. This is not required if the call is part of another expression (although whole instructions must also be terminated by semicolons).