java.io.NotSerializableException: org.zkoss.chart.ChartsEngine

	at java.base/java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1185)
	at java.base/java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1553)
	at java.base/java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1510)
	at java.base/java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1433)
	at java.base/java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1179)
	at java.base/java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:349)
	at TestComponentDeserialization.writeAndReadBack(TestComponentDeserialization.java:30)
	at TestComponentDeserialization.testComponentDeserialization(TestComponentDeserialization.java:22)
	at TestComponentDeserialization.testCharts(TestComponentDeserialization.java:15)
...