What is "jcombobox"

A Jcombobox is a component that combines an editable button or field and a drop-down list. The user can select a value from the drop-down list, which appears in the user request. If you make this component editable, then an editable field is included in which the user can enter a value.

Source: https://docs.oracle.com/javase/9/docs/api/javax/swing/JComboBox.html