JFileChooser is a component in Java Swing that provides a file selection dialog for the user to choose a file or directory. It can be used to select a single file, multiple files, or a directory.

To use JFileChooser in your Java application, you need to create an instance of it and set its properties as desired. You can set the file filter to limit the selection to certain file types, set the default directory to open, and set other options. Once you have created the JFileChooser instance, you can display the dialog to the user by calling the showOpenDialog or showSaveDialog method, depending on whether you want to select a file for opening or saving.

Here is an example of using JFileChooser to open a file:

JFileChooser chooser = new JFileChooser();
int result = chooser.showOpenDialog(null);
if (result == JFileChooser.APPROVE_OPTION) {
    File selectedFile = chooser.getSelectedFile();
    // do something with the selected file
}

In this example, the JFileChooser dialog is displayed using the showOpenDialog method. If the user selects a file and clicks the "Open" button, the getSelectedFile method returns the selected file as a File object. You can then use this file in your application as needed.