Refactorizes the backend

Some backend classes have been refactorized and simplified.

src/main/java/es/uvigo/esei/daa/DAAExampleApplication.java

@@ -24,8 +24,10 @@ import es.uvigo.esei.daa.rest.UsersResource;
 public class DAAExampleApplication extends Application {
 	@Override
 	public Set<Class<?>> getClasses() {
-		return Stream.of(PeopleResource.class, UsersResource.class)
-			.collect(toSet());
+		return Stream.of(
+			PeopleResource.class,
+			UsersResource.class
+		).collect(toSet());
 	}
 	
 	@Override

src/main/java/es/uvigo/esei/daa/dao/DAO.java

@@ -5,7 +5,6 @@ import java.sql.SQLException;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
-import javax.naming.Context;
 import javax.naming.InitialContext;
 import javax.naming.NamingException;
 import javax.sql.DataSource;
@@ -27,11 +26,8 @@ public abstract class DAO {
 	 * Constructs a new instance of {@link DAO}.
 	 */
 	public DAO() {
-		Context initContext;
 		try {
-			initContext = new InitialContext();
-			
-			this.dataSource = (DataSource) initContext.lookup(JNDI_NAME);
+			this.dataSource = (DataSource) new InitialContext().lookup(JNDI_NAME);
 		} catch (NamingException e) {
 			LOG.log(Level.SEVERE, "Error initializing DAO", e);
 			throw new RuntimeException(e);

src/main/java/es/uvigo/esei/daa/dao/UsersDAO.java

@@ -19,6 +19,7 @@ import es.uvigo.esei.daa.entities.User;
 public class UsersDAO extends DAO {
 	private final static Logger LOG = Logger.getLogger(UsersDAO.class.getName());
 	
+	// Yes, SALT should come from external configuration (for example, a property in Tomcat's context).
 	private final static String SALT = "daaexample-";
 	
 	/**

src/main/java/es/uvigo/esei/daa/entities/Person.java

@@ -89,7 +89,7 @@ public class Person {
 			return true;
 		if (obj == null)
 			return false;
-		if (getClass() != obj.getClass())
+		if (!(obj instanceof Person))
 			return false;
 		Person other = (Person) obj;
 		if (id != other.id)