The primary method for combining a number of widgets in a composite
widget is a WContainerWidget. This widget corresponds to an
HTML <span>
or <div>
element (depending on
whether it is inline or not). It can contain any number of children, and
these children may be added or removed dynamically.
Alternatives to consider are a WTemplate, which puts widgets inside an HTML fragment using placeholder substitution, or a WTable for organizing children in a table (without using a layout manager).
As a fundamental building block of JWt, a container widget itself usually does not have any visual aspect (although it can very well be styled to give it for example margin and borders). The widgets that are contained can be positioned using Cascading StyleSheets (CSS) or a Layout Manager. CSS, which to most Java developers will be a new technology, is worthwhile learning as it will allow you to push many layout and style aspects of your application into a declarative text file. It also works irrespective of JavaScript, which is a clear benefit over layout managers. The latter are however the superior (and only) choice in case vertical fitting or stretching of children to the height of the container is needed.
There are several specialized container classes that have additional markup or behaviour: