Vaadin 14 grid with checkboxes as rendered components

Edit: I realize I might have misunderstood the question entirely. If you want to have 3 columns, with each having multiple CheckBoxes where only 1 can be selected per column, then you should use a RadioButtonGroup in each column and bind each to a different Enum field of your griditem class.

Instead of showing how to do three columns with a CheckBox in each, while only one CheckBox can be selected, I will show a different way to achieve the same information about the item.

The reason for this is the solution that what you want to achieve is not easily doable, since each CheckBox is defined in a scope that does not know the other Checkboxes of the same item. Therefore you would need to implement your only-one-selected rule inside the itemclass' setters, which is not optimal. I mean, it is possible, but I'd rather change the structure to something more apt. Usually you don't want to put this kind of business logic into your bean classes.

How would I solve the problem at hand?
Create a new Enum, which will replace all 3 boolean fields in your item class. Now in your grid you will only need one column for a ComboBox to select the enum.
I chose an Enum because this matches your needs here perfectly. With an Enum, you may have several options, but you can select only one (or none).

To better show what I mean, let's use an example Class for the Grid items, Foo. Your version has 3 booleans which your three grid-CheckBoxes are bound to. Let's call them isA, isB, isC.

// your version of the griditem class
public class Foo {
    private boolean isA, isB, isC = false;

    // constructor, getters, setters 
}

// how the columns are added in the grid (approximately) (without editor):
Grid<Foo> grid = new Grid<>();
grid.addComponentColumn((item) -> {
    CheckBox checkBox = new CheckBox();
    checkBox.setValue(item.isA());
    checkBox.addValueChangeListener(event -> item.setA(event.getValue()); // inside setA() method you need to set isB and isC to false if the new value is true. No good!
    return checkBox;
});
grid.addComponentColumn((item) -> {
    CheckBox checkBox = new CheckBox();
    checkBox.setValue(item.isB());
    checkBox.addValueChangeListener(event -> item.setB(event.getValue()); // inside setB() method you need to set isB and isC to false if the new value is true. No good!
    return checkBox;
});
grid.addComponentColumn((item) -> {
    CheckBox checkBox = new CheckBox();
    checkBox.setValue(item.isC());
    checkBox.addValueChangeListener(event -> item.setC(event.getValue()); // inside setC() method you need to set isB and isA to false if the new value is true. No good!
    return checkBox;
});

And here is how it would look after my changes

public class Foo {
    private AbcEnum abcEnum = null;

    // constructor, getters, setters 
}

public Enum AbcEnum {
    A,
    B,
    C;
}

// how the columns are added (without editor):
Grid<Foo> grid = new Grid<>();
grid.addComponentColumn((item) -> {
    ComboBox<AbcEnum> comboBox = new ComboBox<>();
    comboBox.setValue(item.getAbcEnum());
    comboBox.addValueChangeListener(event -> item.setAbcEnum(item.getValue()));
    return comboBox;
});

I wrote "without editor" in the comments about adding the column, because this code will add the ComboBox/CheckBox as clickable and functional components for each grid item, without needing to open the editor for an item to change the values. If you are indeed using an editor, you can add these functional inputs as editorComponents (and bind them to the editor-binder instead of using setValue and addValueChangeListener), and show only the current value in the normal columns (not editable - therefore no inputs like CheckBox or ComboBox are required)