java - Passing object into classes, will they just be references to original? -

this question has answer here:

• is java “pass-by-reference” or “pass-by-value”? 72 answers

this class contains characters , objects within level.

collisionlistener interface, , collisionlistener.begincontact() called whenever character collides object.

i'm wondering, since i'm passing level collisionlistener, mean 2 objects stored in memory?

or private level level inside collisionlistener reference original level? how handled internally jvm?

since when modify level inside collisionlistener, original level updated too.

public class level extends world {      private player player;     private enemy enemy;      public level(){          this.setcontactlistener(             new collisionlistener(this));          player = new player();         enemy = new enemy();     }      /**      * move characters      */     public update(){          player.update();         enemy.update();     } } 

this interface, thats added level object. needs reference level object level.dosomething() can invoked.

public class collisionlistener implements contactlistener{      private level level;      public collisionlistener(level level){          this.level = level;     }      public void begincontact(contact contact) {          this.level.dosomething();     }      /* other interface methods .. */ } 

or private level level inside collisionlistener reference original level? how handled internally jvm?

of course is. deal references objects , copy those. in terms of c/c++ compare references pointers.

since when modify level inside collisionlistener, original level updated too.

if don't want happen, create copy of level instance, e.g. using clonable interface.