Advanced Multi-threading

266. What is the priority of a Thread and how it is used in scheduling?

267. What is the default priority of a thread in Java?

268. What are the three different priorities that can be set on a Thread in Java?

269. What is the purpose of join() method in Thread class?

270. What is the fundamental difference between wait() and sleep() methods?

271. Is it possible to call run() method instead of start() on a thread inJava?

272. What is a daemon thread in Java?

A daemon thread in Java is a low priority thread that does not prevent the JVM from exiting when the program finishes. The thread keeps running. Garbage Collection is an example of daemon thread.

273. How can we make a regular thread Daemon thread in Java?

We can call setDaemon(boolean) method to change a thread to daemon thread before the thread starts.

274. How will you make a user thread into daemon thread if it has already started?

No. We can't make a user thread to daemon thread once it has already started. If we do it by calling setDaemon(), it will throw IllegalThreadStateException.

276. What is a Shutdown hook in Java?

The shutdown hook is a thread that is invoked implicitly by JVM just before the shut down. It can be used to clean up unused resources etc. We can use java.lang.Runtime.addShutdownHook(Thread hook) method to register a new virtual-machine shutdown hook.

277. What is synchronization in Java?

The concept of Synchronization in Java is used in Multi-threading programming.

It is a feature in Java that helps in controlling the access of multiple threads to a shared resource.

It is used to prevent Deadlock between multiple threads.

278. What is the purpose of Synchronized block in Java?

279. What is static synchronization?

280. What is a Deadlock situation?

281. What is the meaning of concurrency?

282. What is the main difference between process and thread?

283. What is a process and thread in the context of Java?

284. What is a Scheduler?

285. What is the minimum number of Threads in a Java program?

286. What are the properties of a Java thread?

287. What are the different states of a Thread in Java?

288. How will you set the priority of a thread in Java?

289. What is the purpose of Thread Groups in Java?

290. Why we should not stop a thread by calling its stop() method?

291. How will you create a Thread in Java?292.How can we stop a thread in the middle of execution in Java?

293. How do you access the current thread in a Java program?

294. What is Busy waiting in Multi-threading?

295. How can we prevent busy waiting in Java?

296. Can we use Thread.sleep() method for real-time processing in Java?

297. Can we wake up a thread that has been put to sleep by using Thread.sleep() method?

298. What are the two ways to check if a Thread has been interrupted?

299. How can we make sure that Parent thread waits for termination of Child thread?

300. How will you handle InterruptedException in Java?

301. Which intrinsic lock is acquired by a synchronized method in Java?

302. Can we mark a constructor as synchronized in Java?

303. Can we use primitive values for intrinsic locks?

304. Do we have re-entrant property in intrinsic locks?

305. What is an atomic operation?

306. Can we consider the statement i++ as an atomic operation in Java?

307. What are the Atomic operations in Java?

308. Can you check if following code is thread-safe?

309. What are the minimum requirements for a Deadlock situation in a program?

310. How can we prevent a Deadlock?

311. How can we detect a Deadlock situation?

312. What is a Livelock?

313. What is Thread starvation?

314. How can a synchronized block cause Thread starvation in Java?

315. What is a Race condition?

316. What is a Fair lock in multi-threading?

317. Which two methods of Object class can be used to implement a Producer Consumer scenario?

318. How JVM determines which thread should wake up on notify()?

319. Check if following code is thread-safe for retrieving an integer value from a Queue?

320. How can we check if a thread has a monitor lock on a given object?

321. What is the use of yield() method in Thread class?

322. What is an important point to consider while passing an object from one thread to another thread?

323. What are the rules for creating Immutable Objects?

324. What is the use of ThreadLocal class?

325. What are the scenarios suitable for using ThreadLocal class?

326. How will you improve the performance of an application by multi-threading?

327. What is scalability in a Software program?

328. How will you calculate the maximum speed up of an application by using multiple processors?

329. What is Lock contention in multi-threading?

330. What are the techniques to reduce Lock contention?

331. What technique can be used in following code to reduce Lock contention?

332. What is Lock splitting technique?

333. Which technique is used in ReadWriteLock class for reducing Lock contention?

334. What is Lock striping?

335. What is a CAS operation?

336. Which Java classes use CAS operation?

337. Is it always possible to improve performance by object pooling in a multi-threading application?

338. How can techniques used for performance improvement in a single thread application may degrade the performance in a multi-threading application?

339. What is the relation between Executor and ExecutorService interface?

340. What will happen on calling submit() method of an ExecutorService instance whose queue is already full?

341. What is a ScheduledExecutorService?

342. How will you create a Thread pool in Java?

343. What is the main difference between Runnable and Callable interface?

344. What are the uses of Future interface in Java?

345. What is the difference in concurrency in HashMap and in Hashtable?

346. How will you create synchronized instance of List or Map Collection?

347. What is a Semaphore in Java?348.What is a CountDownLatch in Java?

349. What is the difference between CountDownLatch and CyclicBarrier?

350. What are the scenarios suitable for using Fork/Join framework?

351. What is the difference between RecursiveTask and RecursiveAction class?

352. In Java 8, can we process stream operations with a Thread pool?

353. What are the scenarios to use parallel stream in Java 8?

354. How Stack and Heap work in Java multi-threading environment?

355. How can we take Thread dump in Java?

356. Which parameter can be used to control stack size of a thread in Java?

357. There are two threads T1 and T2? How will you ensure that these threads run in sequence T1, T2 in Java?