What is thread starvation? How do you detect and prevent it?

Starvation happens when a thread is perpetually denied the CPU time or resource access it needs because other threads consistently get priority over it. Common causes include unfair locks that offer no FIFO guarantee, so a thread can keep losing out to newer arrivals indefinitely; locks that are held for a long time, forcing everyone else to queue for an extended period; and extreme thread priority differences that consistently favor higher-priority threads. You can detect starvation by monitoring ThreadMXBean.getThreadCpuTime(id) over time -- a thread that stays in the RUNNABLE state yet accumulates almost no actual CPU time is a strong sign it's being starved. Prevention strategies include using fair locks, such as new ReentrantLock(true), which serves waiting threads in strict arrival order; keeping critical sections as short as possible; never holding a lock across blocking I/O; avoiding extreme differences in thread priority; and using a fair semaphore, such as new Semaphore(N, true).