객체가 스스로 참조하는 객체를 생성하지 않고, 외부 환경(컨테이너)에서 삽입 되는 형태를 DI(Dependency Injection)라고 하네요.. ^^

DI 를 구현하는 방법은 2가지가 있네요..
1. Constructor 방식
2. Setter 방식

-- Constructor 방식 --
public class Shop { private final StockManager stockManager; private final String shopZipCode; public Shop(StockManager stockManager, String shopZipCode) { this.stockManager = stockManager; this.shopZipCode = shopZipCode; } }

-- Setter 방식 --
public class Shop { StockManager stockManager; String shopZipCode; /** * @service name="StockManager" */ public void setStockManager(StockManager stockManager) { this.stockManager = stockManager; } /** * @config name="shopZipCode" */ public void setStockManager(String shopZipCode) { this.shopZipCode= shopZipCode; } // TODO - Joe - how does setter injector do config ? Same way? public void initialize() { // all setXXXs are now done :-) } }

자세한 내용은 요길 참고 : http://www.picocontainer.org/Constructor%2BInjection?print=1