ArrayUtils.java

ArrayUtils.java

public class ArrayUtils {

    public static Object[] flatten(Object[] array){
        Object[] flattenedArray = new Object[0];
        for(int i = 0; i < array.length; i++){
            if(array[i] instanceof Object[]){
                flattenedArray = addAll(flattenedArray, flatten((Object[]) array[i]));
            } else {
                flattenedArray = add(flattenedArray, array[i]);
            }
        }
        return flattenedArray;
    }
    
    private static Object[] add(Object[] array, Object object){
        Object[] newArray = new Object[array.length + 1];
        for(int i = 0; i < array.length; i++){
            newArray[i] = array[i];
        }
        newArray[newArray.length - 1] = object;
        return newArray;
    }
    
    private static Object[] addAll(Object[] array, Object[] objects){
        Object[] newArray = new Object[array.length + objects.length];
        for (int i = 0; i < array.length; i++) {
            newArray[i] = array[i];
        }
        for (int i = array.length; i < newArray.length; i++) {
            newArray[i] = objects[i - array.length];
        }        
        return newArray;
    }
    
    public static Object[] populateSampleArray(){
        // Creating a nested array of objects
        Object[] array = new Object[2];
        array[0] = new Object[3];
        ((Object[]) array[0])[2] = new Object[1];

        // Initialize array indices
        array[1] = 4;
        ((Object[]) array[0])[0] = 1;
        ((Object[]) array[0])[1] = 2;
        ((Object[]) ((Object[]) array[0])[2])[0] = 3;

        return array;
    }
    
}

ArrayUtilsTest.java

import java.io.IOException;

/**
 *
 * @author Seyed Mohammad Hossein Jamali ([email protected])
 */
public class ArrayUtilsTest {

    public static void main(String[] args) throws IOException {

        // Populate a sample array
        Object[] array = ArrayUtils.populateSampleArray();

        // Call flattenArray 
        Object[] result = ArrayUtils.flatten(array);

        // Print contents of final array
        for (int i = 0; i < result.length; i++) {
            System.out.print(result[i] + ",");
        }
    }

}