Java – jtextfield listener when modifying textfield text

I know how to add a text listener on jtextfield, trigger when the text changes, and modify the text of jtextfield during operation

It seems appropriate that I try to use addinputmethodlistener, but it doesn't seem to work I also tried textfield getDocument(). Adddocumentlistener(), but this throws a Java Lang. IllegalStateException: when I try to modify the text of textfield, I try to mutate in the notification

Solution

Documentlisteners cannot modify the underlying document of JTextComponent You are looking for documentfilter

Example