A basic example of a design issue that can be solved with the Strategy pattern.

TeresaExample.java

import java.util.Random;
public abstract class Character {
    private int health;
    public Character(int health) {
        this.health = health;
    }
    public boolean wound(int dmg) {
        this.health = (this.health > dmg) ? this.health-dmg : 0;
        return this.health == 0;
    }
    public int meleeAttack() {
        Random rnd = new Random();
        return rnd.nextInt(6)+rnd.nextInt(6)+rnd.nextInt(6)+3;
    }
    public int rangedAttack() {
        Random rnd = new Random();
        return rnd.next(4)+rnd.next(4)+2;
    }
}
public class Knight extends Character {
    public Knight() {
        super(18);
    }
}
public class Rogue extends Character {
    public Rogue() {
        super(12);
    }
}
public class GiantRat extends Character {
    public GiantRat() {
        super(10);
    }
    @Override
    public int meleeAttack() {
        Random rnd = new Random();
        return rnd.nextInt(4)+rnd.nextInt(4)+2;
    }
}