Foo.java

public final class Foo {
   private final int product = this.getNumber() * 2;
   private final boolean isValid = true;

   public final int getNumber() {
      return this.isValid ? 1 : 0;
   }

   public final int getProduct() {
      return this.product;
   }

   public final boolean isValid() {
      return this.isValid;
   }
}