Find a way to avoid needing to copy the original collection Considering our last approach, it isn’t thread-safe. If we want to resolve our problem with the first option, we may want to useCopyOnWriteArrayList,
List<SomeBean> newList = new ArrayList<SomeBean>(otherList); Note: still not thread safe, if you modify otherList from another thread, then you may want to make that otherList (and even newList) a CopyOnWriteArrayList, for instance -- or use a lock primitive, such as ReentrantReadWrite...
importjava.util.ArrayList;importjava.util.List;publicclassListCopyRangeExample{publicstaticvoidmain(String[]args){List<Integer>originalList=newArrayList<>();originalList.add(1);originalList.add(2);originalList.add(3);originalList.add(4);originalList.add(5);intstartIndex=1;intendIndex=4;List<Integ...
import java.util.ArrayList; import java.util.Collections; public class CollectionsTest { public static void main(String[] args) { ArrayList<Integer> list = new ArrayList<Integer>(); list.add(1); list.add(12); list.add(2); list.add(19); // 排序 Collections.sort(list); // 检索 System...
以下代码是向ArrayList里添加元素,可以发现在添加的时候是需要加锁的,否则多线程写的时候会Copy出N个副本出来。public boolean add(T e) { final ReentrantLock lock = this.lock; lock.lock(); try { Object[] elements = getArray(); int len = elements.length; // 复制出新数组 Object[] newElements ...
How do I clone a generic List in Java? ArrayList copy = new ArrayList (original.size()); Collections.copy(copy, original); origin: stackoverflow.com How to create a copy of ArrayList<ArrayList<Arc>> to another ArrayList<ArrayList<Arc>> for(ArrayList<Arc> list : rotalar1) { ArrayList<...
Below is the java code to perform the Sheet copy using Apache POI 4.1.1 and Java 11: import java.util.ArrayList; import java.util.Iterator; import java.util.List; import java.util.Set; import java.util.TreeSet; import org.apache.poi.ss.usermodel.*; ...
Java publicclassBar{Stringf1;List<Long>f2; }publicclassFoo{intf1;List<Integer>f2;Map<String,Integer>f3;List<Bar>f4; }RowEncoder<Foo>encoder=Encoders.bean(Foo.class);Foofoo=newFoo();foo.f1=10;foo.f2=IntStream.range(0,1000000).boxed().collect(Collectors.toList());foo.f3=IntStream.rang...
Acess an arraylist from another class? Activator.Createinstance for internal constructor Active Directory Error: Unknown Error (0x80005000) Active Directory problem: Check if a user exists in C#? Active Directory User does not assign User logon name and User Principal Name AD LDS cannot ChangePassw...
import java.util.ArrayList; def userManager = ComponentAccessor.getUserManager()def groupManager = ComponentAccessor.getGroupManager()def groups = groupManager.getGroupsForUser("A") // user à copier def uu = ComponentAccessor.getUserUtil()def user = uu.getUser("B") // user prenant la copie...