ObscureCoder wrote Your error is rather trivial.
You've messed up the switch statement.
That's the incorrect syntax for a switch statement, you don't use curly braces.

Fixed code:



      while (!monster.eaten(dave)) {
         int move = in.nextInt();
         
         switch (move) {
         case 8:
            dave.moveUp();
            break;
         case 2:
            dave.moveDown();
            break;
         case 4:
            dave.moveLeft();
            break;
         case 6:
            dave.moveRight();
            break;
         default:
            //
         }

         monster.chase(dave);

         dave.printDetails();
         monster.printDetails();
      }



As a side note:
For a boolean method such as isAlive, don't do an if statement for an evaluative expression; just return the expression.


   public boolean isAlive() {
      return (this.lives > 0);
   }


Also, use the methods you create:


   public void loseLife() { // Decrement the lives.
      if(this.isAlive()) {
         this.lives--;
      }
   }


Also, for the printDetails():
1) Don't create a method called printDetails() - that's the kinda unprofessional stuff you get taught in introductory Java lessons. Override every class object's toString() method and print the object.
2) Use System.out.println() more than once if you're wanting newlines. Java is multi platform but that doesn't mean that the newline \n works on all platforms. System.out.println() will end every console line with System.getProperty("line.separator");

There's also no real need to make things messy by referring to "this" all the time.
You can also assign the values of class members outside methods, so.. no need to set them inside the constructor.