You need to learn Java if-else and loops to make this game. Here are some tutorials for that
If - else statement:
You are a person that has taken up an adventure beset with monsters. There are 4 types of monsters here: Skeleton, Zombie, Assassin and Warrior. At each turn you'll face a monster. When facing them , you can attack (you'll receive damage as retribution), you can run away from that monster or you can drink potion. If your health reaches below 1 (from 100) , the game is over. After defeating each monster, you may get a bonus health potion. Finally you have the choice to continue further into the adventure or leave (quit ) the game.