publicclassArraycopyTest{publicstaticvoidmain(String[] args){// TODO Auto-generated method stubint[] a =newint[10]; a[0] =0; a[1] =1; a[2] =2; a[3] =3; System.arraycopy(a,2, a,3,3); a[2]=99;for(inti=0; i < a.length; i++) { System.out.println(a[i]); } }...
高性能JVM中，System.arraycopy()和相关方法java.util.Arrays.copyOf()都被实现为intrinsic method，进行特殊优化。HotSpot VM在编译时根据参数类型和常量值判断，调用高度优化的汇编实现的stub，充分利用当前CPU的SIMD指令提高速度。
1、先来看看基本数据类型的System.arraycopy() 方法拷贝: 1importjava.util.Arrays;2publicclassTestDemo {3publicstaticvoidmain(String[] args) {45int[] array1 =newint[]{1,2,8,7,6};6int[] array2 =newint[array1.length];7System.arraycopy(array1, 0, array2, 0, array1.length);89System....
2019-12-23 15:00 −1.1 Array Initalization First of all, we need know Java arrays is static. When the array is initialized, the length of the array is immutable. The exp... XieXiyu 0 195 JAVA克隆对象报错:The method clone() from the type Object is not visible ...
要理解一下arraycopy方法的参数：arraycopy(Object src, int srcPos, Object dest, int destPos, int length);1、源和目标对象都必须是数组 2、srcPos和destPos都必须保证不越界 3、目标对象可写
The arraycopy() method can be used to copy quickly an array of any type from one place to another. This is much faster than the equivalent loop written out longhand in Java. Here is an example of two arrays being copied by the arraycopy() method. First,
Java程序性能优化-使用'System.arraycopy ()'代替通过来循环复制数组 void method () { int[] array1 = new int [100]; for (int i = 0; i < array1.length; i++) { array1 [i] = i; } int[] array2 = new int [100]; System.arraycopy(array1, 0, array2, 0, 100); }...
当解释器发现热点方法时会调用 CompilerBroker::comple_method()向编译任务队列投递一个编译任务(CompileTask),然后C2编译器线程会在发现任务队列有编译任务时唤醒,拉取编译任务并进入JIT编译器。目光转向C2编译线程(C2 CompilerThread),它最开始阻塞在编译任务队列,在发现编译任务后唤醒,接着经过如代码清单9-1所示的调...
'System.arraycopy ()' 要比通过循环来复制数组快的多。 例子: AI检测代码解析 public class IRB { void method () { int[] array1 = new int [100]; for (int i = 0; i < array1.length; i++) { array1 [i] = i; } int[] array2 = new int [100]; ...
System.arraycopy() （以及相关的 java.util.Arrays.copyOf() ）都会被实现为intrinsic method，JVM内...