FlattenArrays.java

import java.util.ArrayList;
import java.util.List;

public class FlattenArrays {
    List<Integer> temp = new ArrayList<Integer>();
	public int[] flatArray(Object[] input){
		if(input.getClass().isArray()){
			for(int i=0;i<input.length;i++){
				  if(!input[i].getClass().isArray()){
					  temp.add((Integer) input[i]);
				  }
				  else{
				    recursive((Object[])input[i]);
				  }
				}
		}
		int[] array = new int[temp.size()];
		for(int i=0;i<temp.size();i++){
			array[i] =  temp.get(i);
		}
		return array;
	}
	
	
	public void recursive(Object[] input){ 
	  for(int j=0;j<input.length;j++){
	  if(!input[j].getClass().isArray()){
		  temp.add((Integer) input[j]);
	  }
	  else{
		  recursive((Object[])input[j]);
	  }
	}
	}
	public static void main(String[] args) {
		Object[] array = new Object[2];
		array[0] = new Object[3];
		((Object[]) array[0])[0] = 1;
		((Object[]) array[0])[1] = 2;
		((Object[]) array[0])[2] = new Object[1];
		((Object[])((Object[]) array[0])[2])[0] = 3;
		array[1] = 4;
		System.out.print("input : [");
		for(int i=0;i<array.length;i++){
			System.out.print(array[i]);
			if(i<array.length-1)
			System.out.print(",");
		}
		System.out.println("]");
		System.out.println("To be clear the input is [[1,2,[3]],4]");
		FlattenArrays obj = new FlattenArrays();
		int[] arr = obj.flatArray(array);
		System.out.print("output : [");
		for(int i=0;i<arr.length;i++){
			System.out.print(arr[i]);
			if(i<arr.length-1)
			System.out.print(",");
		}
		System.out.print("]");
	}
}