Article directory 1. JUC 2. Processes and threads 3. Concurrency and parallelism 4. User thread and daemon thread 5. Object locks and class locks 6. Synchronized keyword 7. synchronized case 8. Lock interface 1.JUC JUC, the java.util.concurrent toolkit for processing threads, started with JDK1.5, and has three packages: Basic package Atomic package Lock bag 2. […]
Tag: synchronized
The principle of synchronized and the Callable interface
Table of Contents ?synchronized principle ?Lock upgrade ?Lock optimization ?Callable interface ?synchronized principle We know that synchronized locks can control multiple threads’ access to shared resources, and two threads will block and wait when accessing the same variable. The synchronized lock is not static, it will be upgraded according to the situation. ?Lock Upgrade JVM […]
CAS, Synchronized principle
What is CAS CAS application Atomic class spin lock ABA issues with CAS Synchronized principle Lock upgrade optimization Lock elimination optimization Lock coarsening optimization What is CAS What is CAS? Compare and swap: Compare and swap A CAS operation involves: We assume that the original data V in the memory, the old expected value A, […]
java synchronized keyword
Bytecode level 0x0020 [synchronized] will be added to the method flag. Specifically used are monitorenter and monitorexit 0 load_0 1 dup 2 astore_1 3 monitorenter 4 aload_1 5 monitorexit 6 goto 14 (+ 8) 9 astore_2 10 aload_1 11 monitorexit 12 aload_2 13 throw 14 return Why are there two monitorexits? In addition to normal […]
synchronized optimization principle
Article directory 1. Underlying principles 2. Optimization plan one: lightweight lock (1) Lightweight lock workflow (2) Lock expansion 3. Optimization plan two: spin optimization 4. Optimization plan three: bias lock (1) Biased state (2) Batch weight bias (3) Batch re-direction cancellation 5. Optimization plan four: lock elimination 1. Underlying principles First of all, we need […]
synchronized and reentrantlock implement multi-thread synchronization locking
Table of Contents Multithreading: Advantages of multithreading: Disadvantages of multithreading: Solution: Multi-thread synchronization Locking method one: synchronized() Inherit Thread() Implement the Runnable interface Locking method two: reentrantLock implements locking Multi-threading: In an application, there are multiple threads, and different threads can perform tasks in parallel. Multi-threading advantages: Improve program processing capabilities For example: anti-virus software […]
Do you know the underlying principle of the synchronized keyword?
Synchronized [Object Lock] uses a mutually exclusive method so that at most one thread can hold the [Object Lock] at the same time. Other threads will be blocked when they want to acquire this [Object Lock]. The code for grabbing tickets is as follows. If it is not locked, it will be oversold or one […]
JAVA Deepening Chapter_32 – Thread synchronization synchronized syntax structure used by threads [with detailed description and code]
Thread synchronization What is thread synchronization Asking synchronization issues In real life, we will encounter the problem of “multiple people want to use the same resource”. For example: In the classroom, there is only one computer and many people want to use it. The natural solution is to line up next to the computer. After […]
synchronized in Java
In Java, the synchronized keyword is a built-in synchronization mechanism used to control concurrent access to shared resources by multiple threads. When a thread accesses a method or code block modified by synchronized, it will automatically acquire the lock and release the lock when exiting, thereby ensuring that only one thread can execute the code […]
synchronized lock type
Previous articles have talked about the understanding of synchronization locks. The way to implement synchronization locks is nothing more than multiple threads seizing a mutually exclusive variable. If the preemption is successful, it means that the lock has been obtained, while threads that have not obtained the lock will block and wait until the lock […]