[MySQL][Jar] Problems outside the IDE

[Revoke]

My code works very well on NetBeans but I can't run the .jar file in command line, I received these errors:

Exception in thread "main" java.lang.NullPointerException
at cadastro.dao.DadosDao.findDados(DadosDao.java:44)
at cadastro.controller.DadosController.listaDados(Dad osController.java:68)
at cadastro.Principal.<init>(Principal.java:33)
at cadastro.Cadastro.main(Cadastro.java:12)

These are the codes near the errors

DadosDao (findDados around line 44)

public List<Dados> findDados() throws SQLException 
    {
        List<Dados> dadoss = new ArrayList<Dados>();

        String select = "SELECT * FROM dados";

        PreparedStatement stmt = getConnection().prepareStatement(select); //Line 44
        ResultSet rs = stmt.executeQuery();

DadosController( listaDados, around line 68)

public List<Dados> listaDados() 
    {
        DadosDao dao = new DadosDao();
        try 
        {
            return dao.findDados(); //Line 68
	} 
        catch (SQLException e) 
        {
            
            JOptionPane.showMessageDialog(null, "Problemas ao localizar contato\n" + e.getLocalizedMessage());

        }
        
        return null;
	    
    }

Principal (around line 33):

private JFileChooser flImagem;
    private JButton btnSalvar, btnAlterar, btnExcluir, btnClear, btnLocalizar;
    private JButton btnPrimeiro, btnProximo, btnAnterior, btnUltimo, btnAbrir;
    private JButton btnCarregar;
    private List<Dados> contatoList = new DadosController().listaDados(); //Line 33
    private int registroAtual = 0;

[sehudson]

How are you running the jar from the command line, what are you typing in?

If its runnning ok in the IDE, could be a classpath issue. Check the manifest file and see what the path is to the class that has your main method. Probably something like packagename.className. Then try to run it using "java -cp packagename.classname MyJarFile.jar

[Revoke]

I'm doing this
java -jar "/home/lsa/NetBeansProjects/Cadastro/dist/Cadastro.jar" (suggested by the IDE)

I tried the method you just said and got theses errors

Exception in thread "main" java.lang.NoClassDefFoundError: Cadastro.jar
at gnu.java.lang.MainThread.run(libgcj.so.11)
Caused by: java.lang.ClassNotFoundException: Cadastro.jar not found in gnu.gcj.runtime.SystemClassLoader{urls=[], parent=gnu.gcj.runtime.ExtensionClassLoader{urls=[], parent=null}}
at java.net.URLClassLoader.findClass(libgcj.so.11)
at gnu.gcj.runtime.SystemClassLoader.findClass(libgcj .so.11)
at java.lang.ClassLoader.loadClass(libgcj.so.11)
at java.lang.ClassLoader.loadClass(libgcj.so.11)
at gnu.java.lang.MainThread.run(libgcj.so.11)

[Norm]

The error you get on line 44 could be caused by getConnection() returning a null value.
Break line 44 into separate steps and print out the value returned by getConnection() to see if it is null.

The instructions in post#2 are not going to help. You are executing the code ok, but are having a problem there.

The instructions from post#2 should say something like this:
java -cp MyJarFile.jar;. cadastro.Cadastro

[Tolls]

What Norm said.
I would lay good odds that your getConnection() is actually eating an exception and returning a null Connection.
That exception is quite likely to be a ClassNotFoundException (the MySQL connector jar isn't where it should be), or a SQLException (failed to connect).

[Revoke]

the value of getConnection is right, at least on the IDE, it returns the value
com.mysql.jdbc.JDBC4Connection@19fcc69

I really don't know what else to do...

[Tolls]

Then the above code is not the source of that errror.
Line 44 only has one thing on it that can be the cause of your NPE and that is the return value of getConnection() has to be null.

Since you haven't shown us your getConnection() code we can't say why.

Rewrite the top method as:

public List<Dados> findDados() throws SQLException 
    {
        List<Dados> dadoss = new ArrayList<Dados>();

        String select = "SELECT * FROM dados";

        Connection connection = getConnection();
        System.out.println(connection);
        PreparedStatement stmt = connection.prepareStatement(select);
        ResultSet rs = stmt.executeQuery();

and check what the value of connection is.

[Revoke]

The value is "com.mysql.jdbc.JDBC4Connection@253498"

The code for getConnection is here

public static Connection getConnection() 
{
        System.out.println("Conectando ao Banco de Dados");
        
        try 
        {
            //Carrega o Driver do Banco
            Class.forName(DRIVER_CLASS);
            Connection conn = DriverManager.getConnection(URL_MYSQL, USER, PASS);
            if (conn != null) {

                System.out.println("STATUS--->Conectado com sucesso!");
                System.out.println("conn =" +conn);

            } else {

                System.out.println("STATUS--->Não foi possivel realizar conexão");

            }
            return conn;
            
        } 
        
        catch (ClassNotFoundException e) 
        {
            System.out.println("O driver expecificado nao foi encontrado.");
            //e.printStackTrace();
        } 
        catch (SQLException e) 
        {
            System.out.println("Nao foi possivel conectar ao Banco de Dados.");
            //throw new RuntimeException(e);
            return null;
        }
        return null;
    }
}

[Norm]

What is the text of the error messaged now?

[Revoke]

The same message as before

[Revoke]

But outside the IDE it gets the value NULL instead of the value that is used to be....

[JosAH]

But outside the IDE it gets the value NULL instead of the value that is used to be....

Is the .jar file that contains your JDBC driver on your classpath?

kind regards,

Jos

[Norm]

Please post the full text of the error message.

What variable is null? Why is that variable null? Add lots of printlns to show the contents of the variable to see where it is being set to null.

[Revoke]

Is the .jar file that contains your JDBC driver on your classpath?

kind regards,

Jos

No it doesn't, how can I fix this? I really new to Java and .jar files, on my .jar iot only contains the Classes

Norm
the return variable of getConnectiojn is Null, but it happens only outside the IDE

[Norm]

That would be because of the missing class definitions that are in the missing jar file.
You need to add the jar file to the classpath for the java program.
How do you execute your program outside of the IDE?

[Tolls]

        catch (ClassNotFoundException e) 
        {
            System.out.println("O driver expecificado nao foi encontrado.");
            //e.printStackTrace();
        } 
        catch (SQLException e) 
        {
            System.out.println("Nao foi possivel conectar ao Banco de Dados.");
            //throw new RuntimeException(e);
            return null;
        }
        return null;
    }

This is your bug (as I said earlier).
You are eating your exceptions.
You are also treating the failure to actually get a connection (which is the purpose of this method) as a perfectly reasonable event. It isn't. It is a failure in your system and should be throwing an exception, not returning null.

[Revoke]

Norm
I'm using this to run the .jar file

java -jar "/home/lsa/NetBeansProjects/Cadastro/dist/Cadastro.jar"

How do I add the jar file to the classpath?

Tolls

With those exception I can see many errors, like :

Exception in thread "main" java.lang.RuntimeException: com.mysql.jdbc.exceptions.MySQLSyntaxErrorExceptio n: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '????????????????' at line 1
at cadastro.dao.ConnectionDataBase.getConnection(Conn ectionDataBase.java:49)
at cadastro.dao.GenericDao.<init>(GenericDao.java:19)
at cadastro.dao.DadosDao.<init>(DadosDao.java:16)
at cadastro.controller.DadosController.listaDados(Dad osController.java:65)
at cadastro.Principal.<init>(Principal.java:33)
at cadastro.Cadastro.main(Cadastro.java:12)
Caused by: com.mysql.jdbc.exceptions.MySQLSyntaxErrorExceptio n: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '????????????????' at line 1
at com.mysql.jdbc.SQLError.createSQLException(SQLErro r.java:1049)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.ja va:3597)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.ja va:3529)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:19 90)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java :2151)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionIm pl.java:2619)
at com.mysql.jdbc.ConnectionImpl.configureClientChara cterSet(ConnectionImpl.java:1881)
at com.mysql.jdbc.ConnectionImpl.initializePropsFromS erver(ConnectionImpl.java:3496)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(Co nnectionImpl.java:2385)
at com.mysql.jdbc.ConnectionImpl.createNewIO(Connecti onImpl.java:2154)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImp l.java:792)
at com.mysql.jdbc.ConnectionImpl.getInstance(Connecti onImpl.java:377)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonReg isteringDriver.java:305)
at java.sql.DriverManager.getConnection(libgcj.so.11)
at java.sql.DriverManager.getConnection(libgcj.so.11)
at cadastro.dao.ConnectionDataBase.getConnection(Conn ectionDataBase.java:26)
...5 more


But I don't know how to solve any of them, the same errors as before...just with the databases errors now

[Norm]

You can add a Class-path: entry to the manifest file in your jar file.

[Tolls]

What versions of things do you have?
Java, JDBC driver, MySQL, that sort of thing.
Looks like you have a mismatch.

Or something's up with your username and password, or connection string possibly?

You also need to tell us where you are getting these exceptions, what system, and whether this is via the IDE.

And what the getConnection() code now looks like.

[Revoke]

The code of getConnection()

public class ConnectionDataBase {
	 
    private static final String URL_MYSQL = "jdbc:mysql://localhost:3306/hospital";
    private static final String DRIVER_CLASS = "com.mysql.jdbc.Driver";
    private static final String USER = "root";
    private static final String PASS = "lsa1234";

public static Connection getConnection() 
{
        System.out.println("Conectando ao Banco de Dados");
        
        try 
        {
            //Carrega o Driver do Banco
            Class.forName(DRIVER_CLASS);
            Connection conn = DriverManager.getConnection(URL_MYSQL, USER, PASS);
            if (conn != null) {

                System.out.println("STATUS--->Conectado com sucesso!");

            } else {

                System.out.println("STATUS--->Não foi possivel realizar conexão");

            }
            return conn;
            
        } 
        
        catch (ClassNotFoundException e) 
        {
            System.out.println("O driver expecificado nao foi encontrado.");
            e.printStackTrace();
        } 
        catch (SQLException e) 
        {
            System.out.println("Nao foi possivel conectar ao Banco de Dados.");
            throw new RuntimeException(e);

        }
        return null;
    }
}

JDBC driver: 5.1.17
MYSQL: 5.1.54
Java: JDK 6 Update 27 with NetBeans 7.0.1
I'm using Linux Ubuntu 11.04

The password and username are ok!