Why my insert method is giving a java.lang.StackOverflowError, while I am making Heap.

Question

I am making a simple program on Heap Sort. Please review my code, and let me know my error. It maybe that I am using the wrong approach. Thanks in advance.

The insert method take two arguments. Integer key is the element which I need to insert and Integer i is the index of the key which is in another array(ie Main class).

public static void main(String[] args) {
    Integer arr[]={81,67,78,59,32,8,96};
    Main a =new Main();
    for(int i=0;i<arr.length;i++)
    {
    a.insert(arr[i], i);
    }

 public void insert(Integer key, Integer i) {
    int head=0;
    if(temp[head]==null)
    {
    temp[head]=key;
    }
    else
        {
        if(key>=temp[head]){
            Integer j=(2*i)+2;
            i=j;
            insert(key, i);    
        }
        else
        {

        Integer j=(2*i)+1;//Stackoverflow error is coming over here. 
        i=j;
        insert(key,i);
        }
        }
}

Answer 1

似乎除了第一个元素以外，插入另一个元素将使您的方法永远保持自身调用，因为所有执行路径均导致再次调用该方法，但0处的元素为null时例外。

Answer 2

一旦temp [0]不为null，并且密钥大于或等于temp [0]，您将遇到无限递归。