Design HashMap

class MyHashMap {

    /** Initialize your data structure here. */
    List<List<Integer>> hashMap;
    public MyHashMap() {
        hashMap = new ArrayList<>();
    }
    
    /** value will always be non-negative. */
    public void put(int key, int value) {
        List<Integer> temp = new ArrayList<>();
        temp.add(key);
        temp.add(value);
        boolean a = true;
        for(int i = 0; i<hashMap.size(); i++){
            if(hashMap.get(i).get(0).equals(temp.get(0))){
                hashMap.set(i, temp);
                a = false;
                break;
            }
        }
        if(a){
            hashMap.add(temp);
        }
        
    }
    
    /** Returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key */
    public int get(int key) {
        for(int i = 0; i<hashMap.size(); i++){
            if(hashMap.get(i).get(0).equals(key)){
                return hashMap.get(i).get(1);
            }
        }
        return -1;
    }
    
    /** Removes the mapping of the specified value key if this map contains a mapping for the key */
    public void remove(int key) {
        for(int i = 0; i<hashMap.size(); i++){
            if(hashMap.get(i).get(0).equals(key)){
                hashMap.remove(i);
            }
        }
    }
}

/**
 * Your MyHashMap object will be instantiated and called as such:
 * MyHashMap obj = new MyHashMap();
 * obj.put(key,value);
 * int param_2 = obj.get(key);
 * obj.remove(key);
 */