LeetCode Combinations

Given two integers n and k, return all possible combinations of k numbers out of 1 ... n.

For example,
If n = 4 and k = 2, a solution is:

[
  [2,4],
  [3,4],
  [2,3],
  [1,2],
  [1,3],
  [1,4],
]

public class Solution {
    List<List<Integer>> list=new ArrayList<>();
    public List<List<Integer>> combine(int n, int k) {
        List<List<Integer>> currList=new ArrayList<>();
            if (n==0 || k==0) {
                return list;
            }
            
        for (int i = 0; i < n; i++) {
            List<Integer> ele=new ArrayList<>();
            ele.add(i+1);
            currList.add(ele);
        }
        list.addAll(currList);
        currList.clear();
        if (k==1) {
            return list;
        }
                
            
            for (int i = 2; i <= k; i++) {
                for (List<Integer> l : list) {
                    for (int j = l.get(l.size()-1)+1; j <=n; j++) {
                        ArrayList<Integer> newlist=new ArrayList<>();
                        newlist.addAll(l);
                        newlist.add(j);
                        currList.add(newlist);
                    }
                }
                list.clear();
                list.addAll(currList);
                currList.clear();
            }
    return list;
    
    }
    
}