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POmysql connect perfectly first time, second time return a nullpointer
 

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  1. POmysql connect perfectly first time, second time return a nullpointer
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    <p>This is my connection Class/Method:</p> <pre><code>static Connection connection = null; Statement stm = null; public static Connection getConexao() { try { // Carregando o JDBC Driver padrão String driverName = "com.mysql.jdbc.Driver"; Class.forName(driverName); // Configurando a nossa conexão com um banco de dados// String serverName = "192.168.0.222"; //caminho do servidor do BD String mydatabase ="bd"; //nome do seu banco de dados String url = "jdbc:mysql://" + serverName + "/" + mydatabase; String username = "user"; //nome de um usuário de seu BD String password = "pass"; //sua senha de acesso connection = DriverManager.getConnection(url, username, password); return connection; } catch (ClassNotFoundException e) { //Driver não encontrado System.out.println("O driver expecificado nao foi encontrado."); return null; } catch (SQLException e) { //Não conseguindo se conectar ao banco System.out.println("Nao foi possivel conectar ao Banco de Dados."); return null; } } </code></pre> <p>method that are called when the TextField lost focus :</p> <pre><code>private void puxaemailsiscart(String servico) throws SQLException { Connection conn = ConectaBD.getConexao(); Statement stm = null; ResultSet results = null; stm = conn.createStatement (); try { System.out.println(); results = stm.executeQuery ("SELECT * FROM " + servico + " WHERE protocolo =" + tfProtocolo.getText()); if(results.next()) { tfEmailParte.setText(results.getString("Email").toString()); } else { System.out.println("Protocolo nao encontrado"); } results.close(); stm.close(); conn.close(); .... </code></pre> <p>The problem is, the first time the TextField lost the focus, it works PERFECTLY and return the Database result, but when i put the focus in the textfield and it lost focus again, the connection return null, why? since the steps are the same as the first time??</p> <p>STACKTRACE</p> <pre><code>Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at telaprincipal$3.puxaemailsiscart(telaprincipal.java:499) at telaprincipal$3.focusLost(telaprincipal.java:482) </code></pre> <p>Line 499: = <code>Connection conn = ConectaBD.getConexao();</code> says that here is the NullPoint, but Why? </p>
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    1. This table or related slice is empty.
    1. USuser2582318
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    1. This table or related slice is empty.
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    1. PO
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    1. VO
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      1. POmysql connect perfectly first time, second time return a nullpointer
      1. This table or related slice is empty.
      1. VTUpMod
    1. COIs `ConectaBD` a class instance (an object) or the class itself?
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      1. POmysql connect perfectly first time, second time return a nullpointer
      1. USSotirios Delimanolis
    2. COYour `getConexao` method returns null if an exception is thrown (having effectively swallowed the exception without logging its details, I note) but you're using the return value regardless.
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      1. POmysql connect perfectly first time, second time return a nullpointer
      1. USJon Skeet
    3. COdo you get System.out.println("O driver expecificado nao foi encontrado."); or System.out.println("Nao foi possivel conectar ao Banco de Dados."); on your console?
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      1. POmysql connect perfectly first time, second time return a nullpointer
      1. USJohnnyAW
 

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