Answer 1

Swing is a GUI widget toolkit for Java. It is part of Oracle's Java Foundation Classes (JFC) – an API for providing a graphical user interface (GUI) for Java programs.

It was developed to provide a more sophisticated set of GUI components than the earlier Abstract Window Toolkit (AWT). It provides a look and feel that emulates the look and feel of several platforms, and also supports a pluggable look and feel that allows applications to have a look and feel unrelated to the underlying platform. It has more powerful and flexible components than AWT. In addition to familiar components such as buttons, check boxes and labels, Swing provides several advanced components such as tabbed panel, scroll panes, trees, tables, and lists.

In December 2008, Sun Microsystems (Oracle's predecessor) released the CSS / FXML based framework that it intended to be the successor to Swing, called JavaFX.

___
THIS ANSWER FROM WIKIPEDIA YOU CAN FIND IT HERE.
https://en.m.wikipedia.org/wiki/Swing_(Java)