'Java Maven Application building successfully but giving the "Cannot invoke "java.net.URL.toExternalForm()" Error and no screen shows up
I am trying to put images into my maven java application but it gives me an error ( Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException: Cannot invoke "java.net.URL.toExternalForm()" because "location" is null). I tried moving the images into the resources folder (NetBeansProjects\hms_02\src\main\java\com\mycompany\hms_02\resources\LogoSmall.png), as suggested by people who faced a similar problem but it didn't work for me. Can anyone please help me figure out the problem?
I am using JFrame in the Netbeans IDE to design my login page. Following is the initComponents() code:
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jPanel1 = new javax.swing.JPanel();
Help_btn = new javax.swing.JButton();
jButton1 = new javax.swing.JButton();
Logo = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
jTextField1 = new javax.swing.JTextField();
jPasswordField1 = new javax.swing.JPasswordField();
jButton2 = new javax.swing.JButton();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setTitle("Login ");
setBackground(new java.awt.Color(255, 255, 255));
setBounds(new java.awt.Rectangle(73, 34, 800, 500));
setLocationByPlatform(true);
getContentPane().setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());
jPanel1.setBackground(new java.awt.Color(255, 255, 255));
Help_btn.setFont(new java.awt.Font("Segoe UI", 0, 16)); // NOI18N
Help_btn.setForeground(new java.awt.Color(18, 76, 144));
Help_btn.setText("Help");
Help_btn.setBorderPainted(false);
Help_btn.setContentAreaFilled(false);
Help_btn.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
Help_btnActionPerformed(evt);
}
});
jButton1.setFont(new java.awt.Font("Segoe UI", 0, 16)); // NOI18N
jButton1.setForeground(new java.awt.Color(18, 76, 144));
jButton1.setText("Sign Up");
jButton1.setBorderPainted(false);
jButton1.setContentAreaFilled(false);
Logo.setIcon(new javax.swing.ImageIcon(getClass().getResource("/com/mycompany/hms_02/resources/LogoSmall.png"))); // NOI18N
jLabel2.setFont(new java.awt.Font("Segoe UI", 0, 30)); // NOI18N
jLabel2.setForeground(new java.awt.Color(18, 76, 144));
jLabel2.setText("Hospital Management System");
jTextField1.setFont(new java.awt.Font("Segoe UI", 0, 12)); // NOI18N
jTextField1.setForeground(new java.awt.Color(102, 102, 102));
jTextField1.setCaretColor(new java.awt.Color(18, 76, 144));
jPasswordField1.setText("jPasswordField1");
jButton2.setBackground(new java.awt.Color(221, 243, 248));
jButton2.setFont(new java.awt.Font("Segoe UI", 0, 20)); // NOI18N
jButton2.setForeground(new java.awt.Color(18, 76, 144));
jButton2.setText("Login ");
jButton2.setBorderPainted(false);
jLabel3.setFont(new java.awt.Font("Segoe UI", 0, 18)); // NOI18N
jLabel3.setForeground(new java.awt.Color(16, 67, 126));
jLabel3.setText("Username");
jLabel4.setFont(new java.awt.Font("Segoe UI", 0, 18)); // NOI18N
jLabel4.setForeground(new java.awt.Color(16, 67, 126));
jLabel4.setText("Password");
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addContainerGap()
.addComponent(jButton1)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(Help_btn)
.addContainerGap())
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(122, 122, 122)
.addComponent(Logo, javax.swing.GroupLayout.PREFERRED_SIZE, 116, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 412, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(144, Short.MAX_VALUE))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
.addComponent(jLabel4, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jLabel3, javax.swing.GroupLayout.DEFAULT_SIZE, 92, Short.MAX_VALUE))
.addGap(30, 30, 30)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jTextField1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.PREFERRED_SIZE, 245, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jPasswordField1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.PREFERRED_SIZE, 245, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(245, 245, 245))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(333, 333, 333))))
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addContainerGap()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(Help_btn, javax.swing.GroupLayout.PREFERRED_SIZE, 29, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton1))
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(18, 18, 18)
.addComponent(Logo))
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(52, 52, 52)
.addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 59, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGap(66, 66, 66)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 37, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel3))
.addGap(18, 18, 18)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jPasswordField1, javax.swing.GroupLayout.PREFERRED_SIZE, 37, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel4))
.addGap(68, 68, 68)
.addComponent(jButton2)
.addContainerGap(76, Short.MAX_VALUE))
);
getContentPane().add(jPanel1, new org.netbeans.lib.awtextra.AbsoluteConstraints(0, 0, 800, 500));
pack();
}
Here's my main:
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(Login_Screen.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Login_Screen.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Login_Screen.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Login_Screen.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable(){
public void run() {
Login_Screen ls =new Login_Screen();
ls.pack();
ls.setVisible(true);
// new Login_Screen().setVisible(true);
}
});
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
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