Final answer:
A type of thread that ends when the app ends is referred to as a daemon thread, which runs in the background and is terminated when all non-daemon threads finish. Non-daemon threads, or 'user' threads, are the main threads of an application that need to be completed before the app can fully terminate.
Step-by-step explanation:
A type of thread that ends when the app ends is called a daemon thread or a non-daemon thread depending on the context.
In programming, specifically in the context of multi-threading in applications, threads can be categorized based on their behavior and lifecycle. A daemon thread is a low-priority thread that runs in the background to perform tasks such as garbage collection or to perform periodic operations. These threads are not meant to be directly serviced by the application, and they are typically terminated by the JVM when all non-daemon, or 'user', threads finish their execution. The main distinction of a daemon thread is that it does not prevent the JVM from exiting once all user threads have finished their execution. Consequently, when the application ends, daemon threads are abruptly terminated.
On the other hand, non-daemon threads, often referred to as 'user' threads, are threads that the JVM waits for before terminating. These threads are typically the main execution threads of an application, and they carry out the work for which the application was intended. When the application ends, user threads have to complete their tasks or reach a stopping point as determined by the application's logic before the application can fully terminate.