System.arraycopy() in Java
Last Updated : 27 Jun, 2022
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java.lang.System class provides useful methods for standard input and output, for loading files and libraries or to access externally defined properties. The java.lang.System.arraycopy() method copies a source array from a specific beginning position to the destination array from the mentioned position. No. of arguments to be copied are decided by an argument. The components at source_Position to source_Position + length - 1 are copied to destination array from destination_Position to destination_Position + length - 1 Class Declaration
public final class System extends Object
Syntax :
public static void arraycopy(Object source_arr, int sourcePos,
Object dest_arr, int destPos, int len)
Parameters :
source_arr : array to be copied from
sourcePos : starting position in source array from where to copy
dest_arr : array to be copied in
destPos : starting position in destination array, where to copy in
len : total no. of components to be copied.Implementation
// Java program explaining System class method - arraycopy()
import java.lang.*;
public class NewClass
{
public static void main(String[] args)
{
int s[] = { 10, 20, 30, 40, 50, 60, 70, 80, 90, 100};
int d[] = { 15, 25, 35, 45, 55, 65, 75, 85, 95, 105};
int source_arr[], sourcePos, dest_arr[], destPos, len;
source_arr = s;
sourcePos = 3;
dest_arr = d;
destPos = 5;
len = 4;
// Print elements of source
System.out.print("source_array : ");
for (int i = 0; i < s.length; i++)
System.out.print(s[i] + " ");
System.out.println("");
System.out.println("sourcePos : " + sourcePos);
// Print elements of source
System.out.print("dest_array : ");
for (int i = 0; i < d.length; i++)
System.out.print(d[i] + " ");
System.out.println("");
System.out.println("destPos : " + destPos);
System.out.println("len : " + len);
// Use of arraycopy() method
System.arraycopy(source_arr, sourcePos, dest_arr,
destPos, len);
// Print elements of destination after
System.out.print("final dest_array : ");
for (int i = 0; i < d.length; i++)
System.out.print(d[i] + " ");
}
}
Output:
source_array : 10 20 30 40 50 60 70 80 90 100 sourcePos : 3 dest_array : 15 25 35 45 55 65 75 85 95 105 destPos : 5 len : 4 final dest_array : 15 25 35 45 55 40 50 60 70 105
