System.arraycopy() （以及相关的 java.util.Arrays.copyOf() ）都会被实现为intrinsic method，JVM内...
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。
System.arraycopy() （以及相关的 java.util.Arrays.copyOf() ）都会被实现为intrinsic method，JVM内...
Methods inherited from class java.lang.Object clone,equals,finalize,getClass,hashCode,notify,notifyAll,toString,wait,wait,wait Method Detail newInstance public staticObjectnewInstance(Class<?> componentType, int
static JNINativeMethod methods[] = { {"currentTimeMillis", "()J", (void *)&JVM_CurrentTimeMillis}, {"nanoTime", "()J", (void *)&JVM_NanoTime}, {"arraycopy", "(" OBJ "I" OBJ "II)V", (void *)&JVM_ArrayCopy}, }; ...
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++) { ...
故即使在客户端指定好了新数组newArray 的大小,接收到返回值后也是指向底层new 出来的数组copy 。换句话说( 也可以因此推出其他的区别) ,在客户端代码中即使不给新数组new 对象,如:String[] newStr = null; 那么对于arraycopy 是会报NullPointerException 的错误的,而对于java.util.Arrays 中的copyOf 方法则由...
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
System.arraycopy(src,0, dest, 0, 4);for(Object o : dest) { System.out.println(o); } } }/*Exception in thread "main" java.lang.NullPointerException at java.lang.System.arraycopy(Native Method) at com.balsam.sources.SystemArrayCopy.main(SystemArrayCopy.java:13)*/ ...
1.1. UsingObject.clone()Method In Java, to create a clone of an array, we should usearray.clone(). It creates a shallow copy of the array. Thedefault cloningalways creates a shallow copy of the array. Any change (in the original array) will also be reflected in the cloned array. ...