Comments on: I need help with this java programming question? http://www.astronomag.com/solarsystem/i-need-help-with-this-java-programming-question Mon, 19 Apr 2010 04:20:59 -0400 http://wordpress.org/?v=2.8.4 hourly 1 By: Nathanael H http://www.astronomag.com/solarsystem/i-need-help-with-this-java-programming-question/comment-page-1#comment-5817 Nathanael H Fri, 26 Feb 2010 21:12:59 +0000 http://www.astronomag.com/solarsystem/i-need-help-with-this-java-programming-question#comment-5817 ArrayLists can contain any object type, as well as a mixture of object types. As such, populating the ArrayList is easy: ArrayList solarSystem = new ArrayList(); //create a PlanetS object for Venus solarSystem.add(/*name of PlanetS object*/); //create a PlanetS object for Mercury solarSystem.add(/*name of PlanetS object*/); //etc etc... The complexity comes when you want to get data out of the ArrayList, as you will have to cast it to the correct type: PlanetS p = (PlanetS) solarSystem.get(1);<br><b>References : </b><br>http://java.sun.com/j2se/1.4.2/docs/api/java/util/ArrayList.html ArrayLists can contain any object type, as well as a mixture of object types. As such, populating the ArrayList is easy:

ArrayList solarSystem = new ArrayList();
//create a PlanetS object for Venus
solarSystem.add(/*name of PlanetS object*/);
//create a PlanetS object for Mercury
solarSystem.add(/*name of PlanetS object*/);
//etc etc…

The complexity comes when you want to get data out of the ArrayList, as you will have to cast it to the correct type:

PlanetS p = (PlanetS) solarSystem.get(1);
References :
http://java.sun.com/j2se/1.4.2/docs/api/java/util/ArrayList.html

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