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POJava NullPointerException when there are no variables not initialiased
 

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  1. POJava NullPointerException when there are no variables not initialiased
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    <p>I am creating this login form using java swing and what I basically do is I get the values from the relevant JtextFields and send them onto another class. Thereafter I check it with the database records. However the program is always displaying a NullPointerException everytime I run it. I tested every variable and saw that none of them contain any Null Values at all.</p> <p>This is the first method (in the LoginPage class) that gets the values from the JTextField</p> <pre><code>public void actionPerformed(ActionEvent e) { String user=textField.getText(); String pass=String.valueOf(passwordField.getPassword()); //try{ //if((user!=null)&amp;&amp;(pass!=null)){ // System.out.println("user is not null"); ui.sendLogin(user,pass); //}else{} //}catch(NullPointerException ex){ //System.out.println("Entered catch block og view"+ex.getMessage()); //} </code></pre> <p>} </p> <p>Thereafter it calls this method (in class LoginController)</p> <pre><code>public void sendLogin(String user, String pass) { try{ System.out.println("values from sendLogin"+user+"pass"+pass); model.verifyUser(user,pass); }catch(NullPointerException ex){ System.out.println("Entered catch block os sendLogin"+ex); ex.printStackTrace(); } } </code></pre> <p>Finally the verifyUser method (in class LoginModel) checks it with the database</p> <pre><code> public void verifyUser(String user,String pass){ String username=""; String password=""; String acc=""; try{ String sql="SELECT * FROM users"; con1.getInstance(); Statement st = con1.getConn().createStatement(); ResultSet rs=st.executeQuery(sql); rs.next(); username=rs.getString("username"); password=rs.getString("password"); acc=rs.getString("accountType"); if(username.equals(user)&amp;&amp;password.equals(pass)){ System.out.println("Logged into the system"); global_username=username; accountType=acc; }else{ System.out.println("Unsuccessful login"+username+user+password+pass); } st.execute(sql); } catch (SQLException s){ System.out.println("SQL statement is not executed!"+s); } } </code></pre> <p>This is the Stack Trace</p> <pre><code>java.lang.NullPointerException at org.application.view.LoginController.sendLogin(LoginController.java:64) at org.application.view.LoginPage$2.actionPerformed(LoginPage.java:94) user is not null values from sendLoginapassabc Entered catch block os sendLoginjava.lang.NullPointerException at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) at javax.swing.AbstractButton$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$000(Unknown Source) at java.awt.EventQueue$1.run(Unknown Source) at java.awt.EventQueue$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source) at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue$2.run(Unknown Source) at java.awt.EventQueue$2.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.AccessControlContext$1.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) </code></pre>
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    1. COHave you checked that `model != null`?
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    2. COAlthough I agree with people suggesting that `model` is `null`, you posted contents of `sendLogin` method twice, while one of them is supposed to be `verifyUser`
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      1. USbesamelsosu
    3. COWhich is LoginController.java line 64? The stack trace indicates that in this line is the error... It could be `model` object or the `verifyUser`function
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      1. USCharliemops
 

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