import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.annotation.Resource;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.RequestScoped;
import javax.sql.DataSource;
import javax.sql.rowset.CachedRowSet;
@ManagedBean
@RequestScoped
public class CustomerBean {
	@Resource(name = "jdbc/mydb")
	private DataSource ds;
	public ResultSet getAll() throws SQLException {
		Connection conn = ds.getConnection();
		try {
			Statement stmt = conn.createStatement();
			ResultSet result = stmt.executeQuery("SELECT * FROM Customers");
			CachedRowSet crs = new com.sun.rowset.CachedRowSetImpl();
			crs.populate(result);
			return crs;
		} finally {
			conn.close();
		}
	}
}

<Context>
<Resource name="jdbc/mydb" 
          auth="Container" 
          type="javax.sql.DataSource"               
          username="app" 
          password="app" 
          driverClassName="org.apache.derby.jdbc.ClientDriver"
          url="jdbc:derby://localhost:1527/COREJSF;create=true"/>
</Context>

Connection conn = ds.getConnection();

import javax.enterprise.context.RequestScoped;
   // вместо    import javax.faces.bean.RequestScoped;

    Context initContext = new InitialContext();
    DataSource ds = (DataSource)initContext.lookup("java:comp/env/jdbc/mydb");

An Error Occurred:
javax.el.ELException: Error reading 'all' on type com.corejsf.CustomerBean

viewId=/index.xhtml
location=C:\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\database\index.xhtml
phaseId=RENDER_RESPONSE(6)

Caused by:
java.lang.NullPointerException - Error reading 'all' on type com.corejsf.CustomerBean
at com.corejsf.CustomerBean.getAll(CustomerBean.java:23)

/index.xhtml at line 15 and column 51 value="#{customerBean.all}"

if(ds == null) return null;