A single-core CPU can support Java multithreading, but the concurrent execution effect of multiple threads will be limited by a single-core CPU.
Java's multithreading is implemented through the Java Virtual Machine (JVM), and the JVM maps threads to underlying operating system threads. Whether it is a single-core CPU or a multi-core CPU, the JVM can create multiple threads and map them to operating system threads.
On a single-core CPU, although there is only one physical processing unit, the operating system can switch between different threads through thread switching and time slice rotation, thereby realizing concurrent execution of multiple threads. When the time slice of a thread runs out, the operating system will save the state of the current thread, and then switch to another thread to continue execution. In this way, multiple threads can be executed alternately, giving the user a feeling of concurrent execution.
However, due to the physical limitation of a single-core CPU, only one thread can execute at a time, while other threads need to wait for their own time slice to execute. This will lead to increased switching overhead and waiting time between threads, thereby reducing the efficiency of concurrent execution of multiple threads.
Generally speaking, a single-core CPU can support Java multi-threading, but the concurrency effect of multi-threading will be limited by physics, and the execution efficiency may not be as good as multi-threading execution on a multi-core CPU.