JavaFX append text to TextArea throws Exception

Question

Answer : JavaFX append text to TextArea throws Exception

I have a thread that calculates the size of a directory.

I use walkFileTree for this.

To get

Answer 1

Ran into same error and as kleopatra's comment stated, FX textarea must be accessed on FX thread.

For simple cases, use Platform.runLater with Java 8 Lambda:

javafx.application.Platform.runLater( () -> taStatus.appendText(file.toString() + "\n") );

If you have many log messages, instead of flooding the FX thread it would be better to buffer them and update TextArea less frequently. Here is an example: https://stackoverflow.com/a/31414801/3710098