Here is my code, it is asking me to call a class, I am confused as to do this. Noob to java, so any help would be greatly appreciated. line 25 is where the error occurs. This program is merging two arrays together into a new array.

public class Merge{

public static void main(String[] args){

    int[] a = {1, 1, 4, 5, 7};
    int[] b = {2, 4, 6, 8};

    int[] mergedArray = merge(a, b);

    for(int i = 0; i < mergedArray.length; i++){
        System.out.print(mergedArray[i] + " ");
    }

}

public static int[] merge(int[] a, int[] b){

    // WRITE CODE  HERE
    int[] mergedArray = new int[a.length[] + b.length[]];
    int i = 0, j = 0, k = 0;

    while (i < a.length() && j < b.length()) //error occurs at this line
    {
        if (a[i] < b[j])

         {

             mergedArray[k] = a[i];
             i++;

         }

         else

         {

             mergedArray[k] = b[j];
             j++;

         }

         k++;

     }

     while (i < a.length())

     {

         mergedArray[k] = a[i];
         i++;
         k++;

     }

     while (j < b.length())

     {

         mergedArray[k] = b[j];
         j++;
         k++;

     }

     return mergedArray;

}

}

This program is merging two arrays together into a new array.