Final answer:
An instance of a listener interface without assigning it to an instance variable is known as an anonymous class, often used for creating simple event handlers in GUI applications.
Step-by-step explanation:
You can create an instance of a listener interface without assigning it to an instance variable by using an anonymous class. An anonymous class is a way of instantiating a new object for which only a single instance is needed, without having to create a named class.
Typically, this is handy when implementing interfaces that may not require extensive functionality or when they are used only once.
For example, if you are handling a button click in a GUI application, you might use an anonymous class to write a quick event handler rather than writing a separate named class just to handle that event.
In Java, you can create an instance of a listener interface without assigning it to an instance variable. This is known as an anonymous class.
An anonymous class is a class that is declared and instantiated at the same time without a name. It is commonly used when you want to create a one-time implementation of an interface or extend a class that won't be used elsewhere.