–> A thread-safe servlet is one that works correctly when more than one thread is running at  the same time.

–> To synchronize access to a method or a block of code, you can use the synchronized  keyword. Then, only one thread at a time can access the code in the block or the method.

–> To prevent multiple threads from accessing the code in a servlet, you can implement the  SingleThreadModel interface. This is a tagging interface that prevents two threads from  accessing the servlet’s service method at the same time.