I'm having trouble with this exception. I have seen some tutorials here, but none of them can solve my problem. Even the answers to similar questions could not satisfy my need.
I'm doing a desktop application with java and SQLite.
I think the error is here, because it only appears at the time of logging, however I followed the tutorial to the letter, but at the time of pressing the enter the error appears:
java.lang.nullpointerexception.
Here is the code for you to review:
private void entrar() {
String sql = "SELECT * FROM logins WHERE usuario = ? and senha = ?";
try {
pst = conn.prepareStatement(sql);
pst.setString(1, nomeUser.getText());
pst.setString(2, senhaUser.getText());
rs = pst.executeQuery();
if(rs.next()){
JOptionPane.showMessageDialog(null, "Login efetuado com sucesso");
}else{
JOptionPane.showMessageDialog(null, "Login inexistente");
}
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e);
}
}
The complete error would be
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at forms.login.entrar(login.java:156)
at forms.login.btnEntrarKeyPressed(login.java:136)
at forms.login.access$100(login.java:21)
at forms.login$2.keyPressed(login.java:83)
at java.awt.Component.processKeyEvent(Component.java:6493)
at javax.swing.JComponent.processKeyEvent(JComponent.java:2832)
at java.awt.Component.processEvent(Component.java:6312)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4891)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1954)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:806)
at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:1074)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:945)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:771)
at java.awt.Component.dispatchEventImpl(Component.java:4762)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Window.dispatchEventImpl(Window.java:2750)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)