1) Vector的方法都是同步的(Synchronized),是线程安全的(thread-safe),而ArrayList的方法不是,由于线程的同步必然要影响性能,因此,ArrayList的性能比Vector好。2) 当Vector或ArrayList中的元素超过它的初始大小时,Vector会将它的容量翻倍,而ArrayList只增加50%的大小,这样,ArrayList就有利于节约内存空间。
Remarks To guarantee the thread safety of theArrayList, all operations must be done through this wrapper. Enumerating through a collection is intrinsically not a thread-safe procedure. Even when a collection is synchronized, other threads can still modify the collection, which causes the enumerator t...
To guarantee the thread safety of the ArrayList, all operations must be done through this wrapper. Enumerating through a collection is intrinsically not a thread-safe procedure. Even when a collection is synchronized, other threads can still modify the collection, which causes the en...
1) Vector的方法都是同步的(Synchronized),是线程安全的(thread-safe),而ArrayList的方法不是,由于线程的同步必然要影响性能,因此,ArrayList的性能比Vector好。 2) 当Vector或ArrayList中的元素超过它的初始大小时,Vector会将它的容量翻倍,而ArrayList只增加50%的大小,这样,ArrayList就有利于节约内存空间。 2. Hashtabl...
i < 10000; i++) { Thread th = new Thread(group, t, String.valueOf(i));th.start();} while (group.activeCount() > 0) { Thread.sleep(10);} System.out.println();System.out.println(t.list1.size()); // it should be 10000 if thread safe collection is used.} } ...
i < 10000; i++) { Thread th = new Thread(group, t, String.valueOf(i));th.start();} while (group.activeCount() > 0) { Thread.sleep(10);} System.out.println();System.out.println(t.list1.size()); // it should be 10000 if thread safe collection is used.} } 首...
ArrayList实现了可变大小的数组。它允许所有元素,包括null。ArrayList没有同步。 size,isEmpty,get,set方法运行时间为常数。但是add方法开销为分摊的常数,添加n个元素需要O(n)的时间。其他的方法运行时间为线性。 每个ArrayList实例都有一个容量(Capacity),即用于存储元素的数组的大小。这个容量可随着不断添加新元素而自...
Vector and Hashtable are two collection classes that are inherently thread safe or synchronized; whereas, the classes ArrayList and HashMap are unsynchronized and must be `wrapped` via Collections.SynchronizedList or Collections.synchronizedMap if synchronization is desired. Vector和Hashtable是线程安全的,...
Gets a value indicating whether access to the ArrayList is synchronized (thread safe). C# Kopioi public virtual bool IsSynchronized { get; } Property Value Boolean true if access to the ArrayList is synchronized (thread safe); otherwise, false. The default is false. Implements IsSynchronized...
importjava.util.ArrayList;importjava.util.List;publicclassArrayListSafeTest{publicstaticvoidmain(String[]args)throws InterruptedException{final List<Integer>list=newArrayList<Integer>();// 线程A将1-1000添加到列表 new Thread(new Runnable() {@Overridepublicvoidrun(){for(int i=1;i<1000;i++){list....