Answer. A type specifies a set of possible values. Every variable has a type, which specifies the kind of values that can be stored in that variable. A constant such as 17 has a type, which tells what kind of value it is. An expression has a type, which tells what kind of value is computed by that expression.

The three most common primitive types in Java are int, double, and boolean. (The complete list of primitive types also includes char, long, short, byte, and float.)

Answer. A literal is a notation (that is, a sequence of character) that is used in a program to represent a constant value. For example, "Hello" is a literal of type String, that represents a constant string value consisting of the sequence of characters H-e-l-l-o. (The quotation marks are part of the literal, but they are not part of the value that is represented!) The literals of type boolean are true and false. Literals of type char are written using single quotation marks, such as 'A', '*', and '\t'.  17 is a literal of type int, and 17L is a literal of type long. (Actually, 17 is a literal of type byte, since it can be represented using 8 bits; however, that's a technicality that rarely makes a difference.)

Answer.

public class Area {
   public static void main(String[] args) {
      String name;
      System.out.print("Please enter your name: ");
      name = TextIO.getln();
      System.out.println("Hello, " + name);
   }
}

Answer.

public class Greet {
   public static void main(String[] args) {
      double number, answer;
      System.out.print("Please enter a number: ");
      number = TextIO.getlnDouble();
      answer = Math.sqrt(number);
      System.out.println("The square root of " + number + " is " + answer);
   }
}