Java 并发系列(二):DCL — Double Check Lock 1. DCL 的目的 Double Check Lock 是多线程环境下为提高延迟初始化效率而被广泛使用的一种方式。我们常常会使用延迟初始化,以降低服务启动时间。 /** * code 1.1 */ @NotThreadSafe public class Client { private LazyInitClass instance ; public LazyInitClass ...
DCL(Double Check Lock)就是为了达到这个目的。 DCL简单来说就是check-lock-check-act,先检查再锁,锁之后再检查一次,最后才执行操作。这样做的目的是尽可能的推迟锁的时间。网上普遍举的一个例子是延迟加载的例子。 public class LazySingleton { private static volatile LazySingleton instance; public static ...
2. Lock contentions will occur frequently at the synchronized blocks in the SynchronizedMap.get() and Synchronized- Map.put() methods. To address these performance problems, we would like to apply these two transformations to the target program in Figure 1: 1. Use the AtomicInteger.addAndGet()...
class Calculator { public void add(int a, int b) { System.out.println(a + b); } public void add(double a, double b) { System.out.println(a + b); } } public class Main { public static void main(String[] args) { Calculator calculator = new Calculator(); calculator.add(1, 2)...
With older versions of Apache Tomcat, certain protocol parameters are expected to be surrounded by double quotes(""). This was the behavior in JDK 7, but was corrected in JDK 8 to be compatible with RFC2617. This caused digest authentication interoperability issues....
Has much better performance than synchronized method. Only the first thread needs to acquire the lock. Best of the above methods. Disadvantages: Double null checks can be confusing at first. Doesn’t work!! Wait what, it doesn’t work?!
A rich set of implementations is provided with underlying data structures (such as array lists, linked lists, or double-end queues) and concurrent behaviors (such as blocking, supporting priorities, or delays). Fine-grained specification of time-out delays, because a large portion of the ...
lock double distanceFromOrigin() { long stamp = sl.tryOptimisticRead(); try { retryHoldingLock: for (;; stamp = sl.readLock()) { if (stamp == 0L) continue retryHoldingLock; // possibly racy reads double currentX = x; double currentY = y; if (!sl...
CONSTANT_Double 6 CONSTANT_NameAndType 12 CONSTANT_Utf8 1 CONSTANT_MethodHandle 15 CONSTANT_MethodType 16 CONSTANT_InvokeDynamic 18 常量池中的各常量项的结构表 Class文件结构中的 cp_info,即常量池中的各常量项的结构表: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 `CONSTANT_Class_info` { u1 ...
dnsjava/dnsjavaPublic NotificationsYou must be signed in to change notification settings Fork247 Star993 Files master Sign in to see the full file tree. Changelog Latest commit ibauersachs Release v3.6.3 Jan 26, 2025 52b59ba·Jan 26, 2025 ...