What are the advantages and disadvantages of using Java’s synchronized keyword for thread synchronization? The synchronized keyword ensures that only one thread can access a block of code at a time. It prevents race conditions and ensures data consistency. However, it can cause performance issues due to thread blocking and context switching. A thread holding the lock may lead to deadlocks or starvation. ReentrantLock provides more flexibility than synchronized, with tryLock() and lockInterruptibly() methods. Unlike synchronized, ReentrantLock supports fair locking mechanisms. However, ReentrantLock requires explicit unlocking, increasing the chance of human errors. Synchronized is simpler and preferred for basic thread synchronization. When should you use ReentrantLock instead of synchronized?