Container : Java Glossary

The term container also refers to any class that holds or organises other objects such as trees, bags and Vectors. Though Java folk usually call those collections to avoid confusion.

A Component can belong to at most one Container at a time. To move a Component between Containers, you must first remove it from the old one then add it to the new one. Similarly you may add a Component to a Container only once, unless you remove it first. You can simulate the effect of a Component moving between Containers by having two Components and keeping only one visible at a time.

Swing uses the same AWT Container class.

Learning More