When I make an TextArea object and I try to set text it works fine when I do something like:

TextArea myTextArea = new TextArea();
myTextArea.setText("some text");

but it fails if I do the following:

TextArea myTextArea = new TextArea();
myTextArea.setText(user.getComments());

where user.getComments() returns a null String value. If user.getComments() returns a non-null String value, it works fine.

The exception stacktrace is the following:

java.lang.IllegalArgumentException: value is null.
at javafx.scene.control.TextInput$TextProperty.set(Unknown Source)
at javafx.scene.control.TextInput.setText(Unknown Source)
at javafx.scene.control.TextArea.setText(Unknown Source)
at gui.UserEdit.setUser(UserEdit.java:619)
at gui.UserList.modifyRegister(UserList.java:529)
at gui.UserList.access$7(UserList.java:521)
at gui.UserList$12.handle(UserList.java:312)
at gui.UserList$12.handle(UserList.java:1)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEventImpl(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEvent(Unknown Source)
at javafx.event.Event.fireEvent(Unknown Source)
at javafx.scene.Scene$ClickGenerator.postProcess(Unknown Source)
at javafx.scene.Scene$ClickGenerator.access$5900(Unknown Source)
at javafx.scene.Scene$MouseHandler.process(Unknown Source)
at javafx.scene.Scene$MouseHandler.process(Unknown Source)
at javafx.scene.Scene$MouseHandler.access$1200(Unknown Source)
at javafx.scene.Scene.impl_processMouseEvent(Unknown Source)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Unknown Source)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(Unknown Source)
at com.sun.glass.ui.View.handleMouseEvent(Unknown Source)
at com.sun.glass.ui.View.notifyMouse(Unknown Source)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(Unknown Source)
at com.sun.glass.ui.win.WinApplication$1$1.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)