title: Exception in thread "main" java.lang.Error: Unresolved compilation problems:
body: <p>This is the error I'm getting</p>
  
  <pre><code>Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
      Scanner cannot be resolved to a type
      Scanner cannot be resolved to a type
  
      at hello.main(hello.java:11)
  </code></pre>
  
  <p>This is my code.</p>
  
  <pre><code>public class hello {
  
      public static void main(String[] args) {
          // TODO Auto-generated method stub
  
          double area;
          double radius;  
  
          Scanner input = new Scanner(System.in);
          System.out.print("반지름을 입력하시오: ");
          radius = input.nextDouble();
          area = 3.14 * radius * radius;
  
          System.out.println(area);
      }    
  }
  </code></pre>