Final answer:
The question concerns Java event handling, where events are categorized based on their type. An example of a single category of events is ActionEvent, used for action-based events like button clicks, and ItemEvent, for item selections or deselections.
Step-by-step explanation:
The question "What are the events displayed under the single category in Java?" seems to be asking about the types of events that can be categorized under a single group within the context of Java programming, typically referring to the Java event handling mechanism.
In Java, events are actions or occurrences that are handled by the program. These events can be user-generated, such as mouse clicks, key presses, and other interactions, or they can be system-generated, indicating changes in the program state. Events are categorized based on the type of action they represent. For instance, ActionEvent is a single category that represents action-based events such as button clicks, menu selections, etc. The java.awt.event package provides a range of event classes and interfaces to handle these events. Another common single category of events could be ItemEvent, which is used to indicate that an item has been selected or deselected.