In Java, thread priority is a way to indicate to the thread scheduler which threads should be given preference when it comes to allocating CPU time. Thread priority is an integer value ranging from 1 to 10, with 1 being the lowest priority and 10 being the highest priority. By default, all threads have a priority of 5.

The thread scheduler can use thread priority to determine which thread to run next when there are multiple threads in the Runnable state. However, the thread scheduler is not required to follow the priority settings and may use a different algorithm to determine which thread to run next.

Here are some important things to note about thread priority in Java:

1. Thread priority is just a suggestion: The thread scheduler is not required to follow the priority settings and may use a different algorithm to determine which thread to run next.

2. Higher priority threads are not guaranteed to execute first: Although higher priority threads are given preference over lower priority threads, it does not necessarily mean that they will execute first. The actual order of execution depends on the thread scheduler.

3. Lower priority threads can starve: If a higher priority thread is constantly being scheduled, it can prevent lower priority threads from ever executing, resulting in a starvation scenario.

4. Thread priority can be changed: The priority of a thread can be changed at any time using the setPriority() method, which is defined in the Thread class.

Here's an example of setting thread priority in Java:

Thread t1 = new Thread(new MyRunnable());
t1.setPriority(Thread.MAX_PRIORITY); // Set the priority to the maximum value (10)
t1.start();

In this example, a new thread t1 is created and its priority is set to the maximum value using the setPriority() method. The thread is then started using the start() method.