Intermediate Swing Containers

Swing provides several general-purpose intermediate containers:

Panel

Panels (JPanel) add almost no functionality beyond what all JComponent objects have.

the most flexible, frequently used intermediate container.
used to group components
can use any layout manager, and you can easily give it a border
content panes of top-level containers are often implemented as JPanel instances.

Scroll Pane

Provides scroll bars around a large or growable component.

Split Pane

Displays two components in a fixed amount of space, letting the user adjust the amount of space devoted to each component.

Tabbed Pane

Contains multiple components but shows only one at a time. The user can easily switch between components.

Tool Bar

Holds a group of components (usually buttons) in a row or column, optionally allowing the user to drag the tool bar into different locations.