Problem med String og java.util.Scanner

Java kode 

 import java.util.Scanner;
 public class Test 
 {
     public static void main(String args[])
     {
         Scanner input = new Scanner(System.in); 
         System.out.println("Do you want to activate the rest of the program?");
         String x = input.nextString();
         //Får fejl: "This method nextString() is undefined for the type Scanner".
         
         if(x = ja)
         {
             System.out.println("You just activated this sentence.");
         }
     }
 }