Java Concurrency. In Practice. Brian Göetz. Tim Peierls. Joshua Bloch. Joseph Bowbeer. David Holmes. Doug Lea. Addison-Wesley Professional. ISBN 2 Concurrency Fundamentals: Deadlocks and Object Monitors . Currently Martin works for an international operating company in the Java EE domain and is. Contribute to evangelist64/java-concurrency development by creating an account on GitHub.
|Language:||English, Portuguese, Dutch|
|ePub File Size:||18.34 MB|
|PDF File Size:||15.27 MB|
|Distribution:||Free* [*Registration needed]|
O The Java Concurrency framework provides a platform to parallelize applications effectively using classes and interfaces provided by the Java Concurrency. Core Java Concurrency. From its creation, Java has supported key concurrency concepts such as threads and locks. This guide helps. Java developers working. implementation of the concurrency features added to the Java platform in Java Java Concurrency in Practice is an invaluable compilation of threading.
A basic question that comes to mind is why do we need such thread pools when we can create objects of java. The answer comes down to two basic facts: Creating a new thread for a new task leads to overhead of thread creation and tear-down. Managing this thread life-cycle significantly adds to the execution time. Adding a new thread for each process without any throttling leads to the creation of a large number of threads.
These threads occupy memory and cause wastage of resources. The CPU starts to spend too much time switching contexts when each thread is swapped out and another thread comes in for execution. All these factors reduce the throughput of the system. Thread pools overcome this issue by keeping the threads alive and reusing the threads.
Any excess tasks flowing in than the threads in the pool can handle are held in a Queue. Once any of threads get free, they pick up the next task from this queue.
Concurrency and synchronization in Java programs
This task queue is essentially unbounded for the out-of-box executors provided by the JDK. Types of Executors Now that we have a good idea of what an executor is, let's also take a look at the different kinds of executors.
SingleThreadExecutor This thread pool executor has only a single thread. It is used to execute tasks in a sequential manner. If the thread dies due to an exception while executing a task, a new thread is created to replace the old thread and the subsequent tasks are executed in the new one. The tasks submitted to the executor are executed by the n threads and if there is more task they are stored on a LinkedBlockingQueue.
Java Concurrency Tutorial
This number is usually the total number of the threads supported by the underlying processor. Unlike the fixed thread pool, the number of threads of this executor pool is not bounded.
If all the threads are busy executing some tasks and a new task comes, the pool will create and add a new thread to the executor. As soon as one of the threads becomes free, it will take up the execution of the new tasks.
If a thread remains idle for sixty seconds, they are terminated and removed from cache. However, if not managed correctly, or the tasks are not short-lived, the thread pool will have lots of live threads.
Concurrency in Java: The Executor Framework
This may lead to resource thrashing and hence performance drop. Understanding the Future Object The result of the task submitted for execution to an executor can be accessed using the java.
Future object returned by the executor. Future can be thought of as a promise made to the caller by the executor.
Instead, whenever the task execution is completed, it is set in this Future object by the executor. The caller can continue executing the main program and when the result of the submitted task is needed he can call.
If the task is complete the result is immediately returned to the caller or else the caller is blocked until the execution of this is completed by the executor and the result is computed. If the caller cannot afford to wait indefinitely before retrieving the result, this wait can be timed as well.
This is achieved by the Future.
Java Concurrency Tutorial
The caller can handle this exception and continue with the further execution of the program. Java Concurrency in Practice is probably the best Java book with detailed focus on multi-threading and Concurrency. It is one of the must read books for core Java learners and developers. The pdf version of the book has been uploaded on dropbox for free and easy download.
It also elaborates how to make it right, and these are probably the most essential things one look for in a good Java book.
You can access Java Concurrency in Practice pdf Download from the download links provided in this post. Java Concurrency in Practice.
Java Concurrency in Practice is divided into four parts. It begins with introduction to a brief history of concurrency; the first part is Fundamentals which consists of chapters such as Thread Safety, Sharing Objects, Composing Objects and Building Blocks. It includes 3 chapters: So, instead of focusing on core Java classes, Java Concurrency in Practice focuses on various concurrency topics, and problems aforementioned.Please enter your name here. The run method is not configured to throw any checked exceptions.
They assume that they can continue to work in a word processor, while other applications download files, manage the print queue, and stream audio. However, developing, testing, and debugging multithreaded programs can still be very difficult; it is all too easy to create concurrent programs that appear to work, but fail when it matters most: in production, under heavy load.
The result is returned by the Future object, which we then print on the screen. This reference will take you through simple and practical approaches while learning Java Concurrency framework provided by Java Programming language.