Exception:
Caused by: java.lang.NullPointerException
at com.gargoylesoftware.htmlunit.html.HtmlInput.executeOnChangeHandlerIfAppropriate(HtmlInput.java:509)
at com.gargoylesoftware.htmlunit.html.HtmlCheckBoxInput.setChecked(HtmlCheckBoxInput.java:122)

Reproduce:

• Create a WebClient with the constructor option javaScriptEngineEnabled=false.
• Load a page with an Checkbox
• Set the checkbox to checked

Location: https://github.com/HtmlUnit/htmlunit/blob/master/src/main/java/com/gargoylesoftware/htmlunit/html/HtmlInput.java#L509

It seems like engine is null in this case:

        final AbstractJavaScriptEngine<?> engine = htmlElement.getPage().getWebClient().getJavaScriptEngine();
        if (engine.isScriptRunning()) {
            return page;
        }