Exception in thread “AWT-EventQueue-0” java.lang.NullPointerException

Boa tarde galera, estou tentando rodar meu programa de cadastro de pessoas mas está dando isso:

Exception in thread “AWT-EventQueue-0” java.lang.NullPointerException
at dao.UsuarioDAO.adiciona(UsuarioDAO.java:28)
at gui.UsuarioGUI$2.actionPerformed(UsuarioGUI.java:98)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

Eu sei que é “AWT-EventQueue-0” java.lang.NullPointerException, mas não consigo encontrar exatamente o erro e repara-lo, mesmo depurando o código (Estou usando o Eclipse).

JButton botaoCadastro = new JButton("Cadastro");
	botaoCadastro.setBounds(10, 325, 100, 25);
	contentPane.add(botaoCadastro);

	botaoCadastro.addActionListener(new ActionListener() {

		@Override
		public void actionPerformed(ActionEvent e) {
			Usuario usuario = new Usuario();
			usuario.setNome(textoNome.getText());
			usuario.setLocal(textoLocal.getText());
			usuario.setContato(textoContato.getText());
			usuario.setEsporte(textoEsporte.getText());

			if ((textoNome.getText().isEmpty()) || (textoLocal.getText().isEmpty())
					|| (textoContato.getText().isEmpty()) || (textoEsporte.getText().isEmpty())) {
				JOptionPane.showMessageDialog(null, "Preencha os campos!", "Ei amiguinho", 2);
			} else {
				UsuarioDAO.adiciona(usuario);
				JOptionPane.showMessageDialog(null, "Usuário " + textoNome.getText() + " inserido com sucesso! ");
				
				new ExibirPerfil(usuario);
			}				
		}
	});
}

Esse é meu botão com ação de cadastrar e minha conexão está abaixo:

public class UsuarioDAO {

static Connection connection;

public UsuarioDAO() throws SQLException {
	connection = ConnectionFactory.getConnection();
}

public static void adiciona(Usuario usuario) {

 PreparedStatement stmt = null;

	try {
		stmt = connection.prepareStatement("INSERT INTO usuario (nome,local,contato,esporte) VALUES (?,?,?,?)");
		stmt.setString(1, usuario.getNome());
		stmt.setString(2, usuario.getLocal());
		stmt.setString(3, usuario.getContato());
		stmt.setString(4, usuario.getEsporte());
		stmt.executeUpdate();

	} catch (SQLException u) {
		throw new RuntimeException(u);
	}
}

public List<Usuario> buscaCombinacao(Usuario usuario) throws SQLException {
	List<Usuario> usuarios = new ArrayList<>();
	String sql = "select * from usuario where esporte = ?";

	try (PreparedStatement stmt = connection.prepareStatement(sql)) {
		stmt.setString(1, usuario.getEsporte());
		ResultSet resultSet = stmt.executeQuery();

		while (resultSet.next()) {
			Usuario user = new Usuario();
			user.setNome(resultSet.getString("nome"));
			user.setEsporte(resultSet.getString("esporte"));
			usuarios.add(user);
		}
	}

	return usuarios;
}

}

Tira o static do atributo connection e do método adiciona.
Você inicializa o connection no construtor, então não faz sentido ser static.

1 curtida

Eu já tentei isso, mas ai me aparece essa mensagem:

É porque você não deve invocar o método adiciona de forma estática.
Você precisa ter um objeto da classe UsuarioDAO.