خطا هنگام اجرا در B4j

[ab.ba 10]

سلام

هنگام اجراي يك برنامه در b4j اين خطا داده ميشود 

B4J Version: 10.00
Parsing code.    (0.00s)
	Java Version: 8
Building folders structure.    (0.01s)
Compiling code.    (0.01s)
Compiling layouts code.    (0.01s)
Organizing libraries.    (0.00s)
Compiling generated Java code.    Error
Picked up _JAVA_OPTIONS: -Xmx1024m
src\b4j\example\main.java:7: error: package javafx.application does not exist
public class main extends javafx.application.Application{