W R I T E   A N D   D E P L O Y   J 2 E E   A P P L I C A T I O N S  

{ 

   DataSource lDataSource = getDataSource(); 

   Connection lConnection = null; 

   PreparedStatement lStatement = null; 

   try { 

      lConnection = lDataSource.getConnection(); 

      lStatement = lConnection.prepareStatement( 

         "SELECT Id, First_Name, Last_Name FROM TestEntity WHERE id = ?" 

      ); 

      int lId = ( (TestBMPEntityPK) mContext.getPrimaryKey() ).id; 

      lStatement.setInt( 1, lId ); 

      ResultSet lResult = lStatement.executeQuery(); 

      lResult.next(); 

      setId( lResult.getInt( 1 ) ); 

      setFirstName( lResult.getString( 2 ) ); 

      setLastName( lResult.getString( 3 ) ); 

      // Because this method used the attribute setter method 

      // the bean is automatically marked as dirty. Therefore 

      // reverse this here because it is obviosly not true 

      makeClean(); 

   } 

   catch ( SQLException se ) { 

      throw new EJBException( "Could not read record from DB: " + se.getMessage() ); 

   } 

   finally { 

      if( lStatement != null ) { 

         try { 

            lStatement.close(); 

         } 

         catch( Exception e ) {} 

      } 

      if( lConnection != null ) { 

         try { 

            lConnection.close(); 

         } 

         catch( Exception e ) {} 

      } 

   } 

} 

Container Managed Persistence (CMP) 

This type of Entity Beans uses an Object   Relational Mapper (O/R Mapper) to store data on 

persistence store and recreated them. Most O/R Mappers supports various databases and 

allows a bean developer to create Entity Beans that are not only server vendor neutral but 

also database vendor neutral. 

Because the CMP implementation is so important and became somewhat complex this book 

explain it in its own chapter 7, so please have a look there. 

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