Check out example codes for "system.arraycopy java". It will help you in understanding the concepts better.

Code Example 1

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.

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