DocumentListener For JTextArea Not Working Correctly

[vsquared]

I am having trouble getting a DocumentListener correctly installed on a JTextArea in Swing. The source code is shown below, followed by the error message. It appears that the insertUpdate method is being called but there is an EventQueue error from the EventDispatchThread for some unknown reason. The code was run in a Thonny editor. It initially opens the window without error, but when I try to enter more text there is a spew of error messages and only one character is initially shown in the text area. With further jostling of the text area the remainder of the text will appear. Any insight or assistance would be greatly appreciated. Thanks.

import jpype
import jpype.imports

jpype.startJVM()

import java
import javax
import platform
from java.awt import *
from javax.swing import *
from javax.swing.event import DocumentListener
from javax.swing.text import AbstractDocument
from javax.swing.text import PlainDocument

if(platform.system() == "Darwin"):
    from Cocoa import NSApp

_wndW = 400
_wndH = 400

@jpype.JImplements(DocumentListener)
class MyDocumentListener:
    @jpype.JOverride
    def __init__(self):
        print("init called.")
    @jpype.JOverride        
    def changedUpdate(event):
        print("changed update")
    @jpype.JOverride 
    def removeUpdate(event):
        print("remove update")
    @jpype.JOverride    
    def insertUpdate(event):
        print("insert update")
        
def buildWnd():
    global txtArea
    global myListener
    global frame
    
    frame = JFrame("Add More Lines of Text")
    frame.setLayout(None)
    frame.setBounds(100,100,400,400)
    txtArea = JTextArea("Jeremiah was a bullfrog.")
    txtArea.setBounds(10, 10, _wndW - 20, 300)
    frame.add(txtArea)
    txtArea.repaint()
    print("Document =",txtArea.getDocument())
    myListener = MyDocumentListener()
    print("myListener =",myListener)
#   This causes an error message and doesn't work correctly
    txtArea.getDocument().addDocumentListener(myListener)
    frame.setVisible(True)
   
# EDT causes EventQueue error
javax.swing.SwingUtilities.invokeLater(buildWnd)
print(platform.system())
if(platform.system() == "Darwin"):    
    NSApp.run()

Error message:

Exception in thread "AWT-EventQueue-0" org.jpype.PyExceptionProxy
	at org.jpype.JPypeContext.createException(Unknown Source)
	at org.jpype.proxy.JPypeProxy.hostInvoke(Native Method)
	at org.jpype.proxy.JPypeProxy.invoke(Unknown Source)
	at jdk.proxy2/jdk.proxy2.$Proxy10.insertUpdate(Unknown Source)
	at java.desktop/javax.swing.text.AbstractDocument.fireInsertUpdate(AbstractDocument.java:226)
	at java.desktop/javax.swing.text.AbstractDocument.handleInsertString(AbstractDocument.java:780)
	at java.desktop/javax.swing.text.AbstractDocument.insertString(AbstractDocument.java:739)
	at java.desktop/javax.swing.text.PlainDocument.insertString(PlainDocument.java:131)
	at java.desktop/javax.swing.text.AbstractDocument.replace(AbstractDocument.java:698)
	at java.desktop/javax.swing.text.JTextComponent.replaceSelection(JTextComponent.java:1339)
	at java.desktop/javax.swing.text.DefaultEditorKit$DefaultKeyTypedAction.actionPerformed(DefaultEditorKit.java:884)
	at java.desktop/javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1810)
	at java.desktop/javax.swing.JComponent.processKeyBinding(JComponent.java:2947)
	at java.desktop/javax.swing.JComponent.processKeyBindings(JComponent.java:2995)
	at java.desktop/javax.swing.JComponent.processKeyEvent(JComponent.java:2909)
	at java.desktop/java.awt.Component.processEvent(Component.java:6403)
	at java.desktop/java.awt.Container.processEvent(Container.java:2266)
	at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5001)
	at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2324)
	at java.desktop/java.awt.Component.dispatchEvent(Component.java:4833)
	at java.desktop/java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1952)
	at java.desktop/java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:883)
	at java.desktop/java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:1150)
	at java.desktop/java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:1020)
	at java.desktop/java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:848)
	at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:4882)
	at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2324)
	at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2780)
	at java.desktop/java.awt.Component.dispatchEvent(Component.java:4833)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:775)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:720)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:714)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:97)
	at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:747)
	at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
	at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:744)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
	at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

This error message appears to be repeated in the console with every keystroke.