There are two arrays that have opened up space , You only need to exchange the contents of two arrays （ The essence is to change the pointer of two array names ）

int[] tem = heapArr[cur];
heapArr[cur] = heapArr[parent];
heapArr[parent]= tem;

Out of nothing （ There is only one array that has opened up space , It needs to duplicate as like as two peas. , And one of the contents changes , The other doesn't change ）

It's time to Open up a space , And then use Arrays.copyOf( Array name （ Source array ）, How long segments do you want to copy （ Start from the beginning of the array Calculation ）) function

for example ：
Arrays.copyOf（Array,Array.length）

tem = Arrays.copyOf(heapArr[cur],2);
heapArr[cur] = Arrays.copyOf(heapArr[child],2);
heapArr[child] = Arrays.copyOf(tem,2);