Help with Error

Hello, I am trying to make a program. However, after I run the project every so often. I get this huge long error. Sometimes, it happens after I run my program once, or after a few times.

java.lang.Exception
	at processing.app.ui.Recent.remove(Recent.java:246)
	at processing.app.ui.Recent.append(Recent.java:294)
	at processing.app.Base.handleOpen(Base.java:1367)
	at processing.app.Base.handleOpen(Base.java:1314)
	at processing.app.Base.handleOpen(Base.java:1303)
	at processing.app.ui.Recent$1.actionPerformed(Recent.java:217)
	at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
	at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
	at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
	at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
	at javax.swing.AbstractButton.doClick(AbstractButton.java:376)
	at com.apple.laf.ScreenMenuItem.actionPerformed(ScreenMenuItem.java:125)
	at java.awt.MenuItem.processActionEvent(MenuItem.java:669)
	at java.awt.MenuItem.processEvent(MenuItem.java:628)
	at java.awt.MenuComponent.dispatchEventImpl(MenuComponent.java:357)
	at java.awt.MenuComponent.dispatchEvent(MenuComponent.java:345)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:763)
	at java.awt.EventQueue.access$500(EventQueue.java:97)
	at java.awt.EventQueue$3.run(EventQueue.java:709)
	at java.awt.EventQueue$3.run(EventQueue.java:703)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:84)
	at java.awt.EventQueue$4.run(EventQueue.java:733)
	at java.awt.EventQueue$4.run(EventQueue.java:731)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:730)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

please post your code or a smaller version of it to demonstrate the error

and welcome to the forum!!