没事写个冒泡排序

int[] a = new int[] {4,3,15};
int k =0;
int aa=0;
for(int i = 0;i<a.length;i++){
aa=  a[i];
for(int j=1;j<a.length-i-1;j++){

if(aa>a[j]){//从小到大排
k=a[i];
a[i]=a[j];
a[j]=k;

}
}

}
System.out.println(a[0]);
System.out.println(a[1]);
System.out.println(a[2]);