java合并有序数组的高效方法是什么

/**
 * 
 ClassName: MergeSortArray <br/>
 * 
 Function: 合并有序数组<br/>
 *   [1, 2, 2, 5]
 *   [3, 4, 7, 8, 9]
 *
 *
 */

public static int[] mergeSortArray(int[] a, int[] b){
        int length1 = a.length, length2 = b.length;
        int[] merge = new int[length1 + length2];
        int i = 0, j = 0, k = 0;
        while(i < length1 && j < length2){
            if(a[i] <= b[j]){
                merge[k++] = a[i++];
            }else{
                merge[k++] = b[j++];
            }
        }
        while(i < length1){
            merge[k++] = a[i++];
        }
        while(j < length2){
            merge[k++] = b[j++];
        }
        return merge;
    }


    public static void main(String[] args) {
        int[] a = {1, 2, 2, 5};
        int[] b = {3, 4, 7, 8, 9};
        int[] merge = mergeSortArray(a, b);
        for(int i = 0; i < merge.length; i++){
            System.out.println(merge[i]);
        }
    }

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