Mortgage for valkrist

import java.lang.*;

   public abstract class Mortgage {
      private double principal, interest, term;

      public Mortgage() {
         balance = 0;
      }
      public Mortgage(double x, double y, double z) {
         principal = x;
    interest = y;
    term = z;
      }
      public void setPrincipal(double x) {
         principal = x;
      }
      public double getPrincipal() {
         return principal;
      }
}