CLIENT - unhandled error in GUI - NoClassDefFoundError

Error type: CLIENT - unhandled error in GUI - NoClassDefFoundError

Client version: 1.4.57-V2 (build: 2025-04-19 14:23)
Java version: 1.8.0_201
Default charset: UTF-8

org/jboss/mx/util/ObjectNameFactory

Stack trace:
org.jboss.remoting.transporter.InternalTransporterServices.(InternalTransporterServices.java:46)
org.jboss.remoting.transporter.TransporterClient.findAlternativeTarget(TransporterClient.java:513)
org.jboss.remoting.transporter.TransporterClient.invoke(TransporterClient.java:484)
com.sun.proxy.$Proxy9.chatFindByRoom(Unknown Source)
mage.remote.SessionImpl.getRoomChatId(SessionImpl.java:726)
mage.client.SessionHandler.getRoomChatId(SessionHandler.java:328)
mage.client.table.TablesPanel.showTables(TablesPanel.java:766)
mage.client.table.TablesPane.showTables(TablesPane.java:51)
mage.client.MageFrame.prepareAndShowServerLobby(MageFrame.java:1336)
mage.client.MageFrame.performConnect(MageFrame.java:969)
and other 16 lines
Root caused by:
java.net.URLClassLoader.findClass(URLClassLoader.java:382)
java.lang.ClassLoader.loadClass(ClassLoader.java:424)
sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
java.lang.ClassLoader.loadClass(ClassLoader.java:357)
org.jboss.remoting.transporter.InternalTransporterServices.(InternalTransporterServices.java:46)
org.jboss.remoting.transporter.TransporterClient.findAlternativeTarget(TransporterClient.java:513)
org.jboss.remoting.transporter.TransporterClient.invoke(TransporterClient.java:484)
com.sun.proxy.$Proxy9.chatFindByRoom(Unknown Source)
mage.remote.SessionImpl.getRoomChatId(SessionImpl.java:726)
mage.client.SessionHandler.getRoomChatId(SessionHandler.java:328)
and other 20 lines

Start by reproducing the GUI connection flow that reaches MageFrame.performConnect and TablesPanel.showTables, then trace the failure through SessionHandler.getRoomChatId and org.jboss.remoting.transporter.InternalTransporterServices. Inspect how the client loads the missing org/jboss/mx/util/ObjectNameFactory class. Done means the client can enter the server lobby without NoClassDefFoundError.

Written by the indexing model from the issue text.