[java] Java - Check if JTextField is empty or not

So I got know this is a popular question and already found the solution. But when I try this it doesn't work properly.

My JTextField is empty and the button isn't enabled. When I write something in my textfield the button doesn't get enabled.

So my program should check this field every second whether it's empty or not. As soon as someone writes something into the textfield the button should be enabled.^^

loginbt = new JButton("Login");
    loginbt.addActionListener(new loginHandler());
    add(loginbt);

    if(name.getText().equals("")) {
        loginbt.setEnabled(false);
    }else {
        loginbt.setEnabled(true);
    }

Try with keyListener in your textfield

jTextField.addKeyListener(new KeyListener() {

        @Override
        public void keyTyped(KeyEvent e) {
        }

        @Override
        public void keyPressed(KeyEvent e) {
            if (text.getText().length() >= 1) {
                button.setEnabled(true);
            } else {
                button.setEnabled(false);
            }
        }

        @Override
        public void keyReleased(KeyEvent e) {
        }

    });

use the following code :

if(name.getText().equals(""))
{
loginbt.disable();
}

The following will return true if the JTextField "name" does not contain text:

name.getText().isEmpty

if(name.getText().hashCode() != 0){
    JOptionPane.showMessageDialog(null, "not empty");
}
else{
    JOptionPane.showMessageDialog(null, "empty");
}

Try this

if(name.getText() != null && name.getText().equals(""))
{
        loginbt.setEnabled(false);
}
else
{
        loginbt.setEnabled(true);
}

What you need is something called Document Listener. See How to Write a Document Listener.

To Check JTextFiled is empty or not condition:

if( (billnotf.getText().length()==0)||(billtabtf.getText().length()==0))

you can use isEmpty() or isBlank() methods regarding what you need.

Returns true if, and only if, length() is 0.

this.name.getText().isEmpty();

Returns true if the string is empty or contains only white space codepoints, otherwise false

this.name.getText().isBlank();

private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // Submit Button        

    String Fname = jTextField1.getText();
    String Lname = jTextField2.getText();
    String Desig = jTextField3.getText();
    String Nic = jTextField4.getText();
    String Phone = jTextField5.getText();
    String Add = jTextArea1.getText();
    String Dob = jTextField6.getText();
    // String Gender;
    // Image

    if (Fname.hashCode() == 0 || Lname.hashCode() == 0 || Desig.hashCode() == 0 || Nic.hashCode() == 0 || Phone.hashCode() == 0 || Add.hashCode() == 0)
    {
        JOptionPane.showMessageDialog(null, "Some fields are empty!");
    }
    else
    {
        JOptionPane.showMessageDialog(null, "OK");
    }
}

Well, the code that renders the button enabled/disabled:

if(name.getText().equals("")) {
    loginbt.setEnabled(false);
}else {
    loginbt.setEnabled(true);
}

must be written in javax.swing.event.ChangeListener and attached to the field (see here). A change in field's value should trigger the listener to reevaluate the object state. What did you expect?