<div>
That link shows you the Pre JDK1.4 way, and the after JDK1.4 way :-)<br />
<br />
Good luck!! &nbsp;<br />
<br />
Tim
</div>


That link shows you the Pre JDK1.4 way, and the after JDK1.4 way :-)

Good luck!!  

Tim

<div>
Can't test this at the moment but try<br />
<br />
<br />
JTextField tf = new JTextField(4);<br />
tf.setDocument(new FourCharDoc());<br />
<br />
.....<br />
<br />
class FourCharDoc extends PlainDocument {<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;public void insertString(int offs,String str,AttributeSet a) throws BadLocationException {<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (getLength() &lt;&nbsp;4)<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;super.insertString(offs,st<wbr />r,a);<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
}<br />

</div>


Can't test this at the moment but try


JTextField tf = new JTextField(4);
tf.setDocument(new FourCharDoc());

.....

class FourCharDoc extends PlainDocument {
      public void insertString(int offs,String str,AttributeSet a) throws BadLocationException {
            if (getLength() < 4)
                  super.insertString(offs,str,a);
      }
      
}


<div>
Didn't see that link before post sorry. Use the code they give, not mine.
</div>


Didn't see that link before post sorry. Use the code they give, not mine.

<div>
<div class="content wysiwyg-content">
Hello everyone,<br />
&nbsp; &nbsp; &nbsp;I cannot seem to find a way how to restrict the number of charachters in a JTextbox. I know that there is this Constructor where you can pass the COLUMN size but that doesnt work. Java 1.4 has this JFormattedTextbox where you can set the mask and specify something like &quot;####&quot; to restrict the entries to only 4 charachters, but that has a problem. By default it puts blanks in the textfield and that is a problem. <br />
Thanks<br />
- Adil
</div>
</div>


Hello everyone,
     I cannot seem to find a way how to restrict the number of charachters in a JTextbox. I know that there is this Constructor where you can pass the COLUMN size but that doesnt work. Java 1.4 has this JFormattedTextbox where you can set the mask and specify something like "####" to restrict the entries to only 4 charachters, but that has a problem. By default it puts blanks in the textfield and that is a problem. 
Thanks
- Adil

How to restrict Charachters in JTextbox

Java is a platform-independent, object-oriented programming language and run-time environment, designed to have as few implementation dependencies as possible such that developers can write one set of code across all platforms using libraries. Most devices will not run Java natively, and require a run-time component to be installed in order to execute a Java program.