How to disable a button in Java?

I have a Java code and this code creates a GUI. In this GUI, I would like to disable a button if certain condition (let's say none of the check boxes are selected) is not satisfied.

This is how I create the button:

        item23 = new ToolItem(custToolBar22.getToolBar(), SWT.PUSH);
        item23.setImage(image_navigate_right); item23.setText("Run checks"); item23.setToolTipText("Run the checks against the files you selected");
        item23.addListener(SWT.Selection, toolBarListener); 

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In here, I would like to set change image_navigate_right with a grayed out image and I want it to be not clickable.

How can I do it?