Trying to refresh TextArea in thread with "\n" drops error. Over run() method it works fine.

Exception in thread "Thread-4" java.lang.IllegalStateException: Not on FX application thread; currentThread = Thread-4
at com.sun.javafx.tk.Toolkit.checkFxUserThread(Toolkit.java:190)
at com.sun.javafx.tk.quantum.QuantumToolkit.checkFxUserThread(QuantumToolkit.java:336)
at javafx.scene.Parent$2.onProposedChange(Parent.java:270)
at com.sun.javafx.collections.VetoableObservableList.add(VetoableObservableList.java:143)
at com.sun.javafx.scene.control.skin.TextAreaSkin$12.onChanged(TextAreaSkin.java:417)
at com.javafx.preview.control.TextArea.fireParagraphListChangeEvent(TextArea.java:392)
at com.javafx.preview.control.TextArea.access$200(TextArea.java:24)
at com.javafx.preview.control.TextArea$TextAreaContent.insert(TextArea.java:138)
at com.javafx.preview.control.TextInput$TextProperty.store(TextInput.java:102)
at com.javafx.preview.control.TextInput$TextProperty.set(TextInput.java:87)
at com.javafx.preview.control.TextInput.setText(TextInput.java:187)
at com.javafx.preview.control.TextArea.setText(TextArea.java:367)
at hostPing.run(hostPing.java:205)
at java.lang.Thread.run(Unknown Source)

Sample code:
@Override
public void run() {
while (isStart) {
try {
p.openPort();
responseBox.setText(p.response+"\n");
} catch (InterruptedException e) {
// TODO Auto-generated catch block

}

Without "\n" ok.