“Even if your program never explicitly creates a thread, frameworks may create threads on your behalf, and code called from these threads must be thread-safe. This can place a significant design and implementation burden on developers, since developing thread-safe classes requires more care and analysis than developing non-thread-safe classes. Every Java application uses threads. When the JVM starts, it creates threads for JVM housekeeping tasks (garbage collection, finalization) and a main thread for running the main method. The”