JavaFX Properties in TableView

One somewhat strange part of the property API is that IntegerProperty implements ObservableValue<Number>, not ObservableValue<Integer>. So, somewhat counterintuitively, you need

TableColumn<Person, Number> ageColumn = new TableColumn<Person, Number>("Age");

As an aside, and I'm not sure if this causes problems, but it's more usual to use int instead of Integer for the return type for the get method and the parameter type for the set method in your model class. These match the types for IntegerProperty.get() and IntegerProperty.set(...), so it just avoids some implicit auto (un)boxing.

you can use .asObject Method to make your code work
it doesn't need you to change the TableColumn Paramater to Number

ageColumn.setCellValueFactory(cellData -> cellData.getValue().ageProperty().asObject());

idk which one is better code,
change the parameter to Number or use asObject Method

related Link

For String type :

firstNameColumn.setCellValueFactory(cellData -> cellData.getValue().firstNameProperty());

When you want to use IntegerProperty or DoubleProperty, the setCellValueFactory(...) must have an additional asObject():

ageColumn.setCellValueFactory(cellData -> cellData.getValue().ageProperty().asObject());

This is necessary because of a bad design decision of JavaFX.

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