HashMap implementation

HashMap.java

package com.chapters.training;


import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class HashMap<K , V> {

    private Node[] firstNodes;

    private int capacity;

    HashMap() {
        capacity = 16;
        firstNodes = new Node[capacity];
    }

    HashMap(int capacity) {
        this.capacity = capacity;
        firstNodes = new Node[capacity];
    }

    void put(K newKey, V newValue){
        int hashIndex = newKey.hashCode()%capacity;
        if (firstNodes[hashIndex]==null){
            firstNodes[hashIndex] = new Node(newKey,newValue);
            return;
        }
        Node currentVal = firstNodes[hashIndex];
        do {
                if (currentVal.value.equals(newValue)) {
                    return;
                }else {
                    if(currentVal.next==null){
                        currentVal.next = new Node(newKey,newValue);
                        break;
                    }else
                        currentVal = currentVal.next;
                }
        }while(true);
    }

    V get(K searchingKey){
        Node getting = firstNodes[searchingKey.hashCode()%capacity];
        if(getting==null){
            return null;
        }
        do{
            if(getting.key.equals(searchingKey)){
                return (V) getting.value;
            }else{
                if(getting.next==null){
                    return null;
                }else {
                    getting = getting.next;
                }
            }
        }while(true);
    }

    public Set<K> keySet(){
        Set<K> resultSet = new HashSet<>();

        for (Node value : firstNodes){
            if(value==null)
                continue;
            resultSet.add((K)value.key);
            while(value.next!=null){
                value = value.next;
                resultSet.add((K)value.key);
            }
        }
        return resultSet;
    }

    public List<Entry> entrySet() {
        List<Entry> list = new ArrayList<>();
        for (Node node : firstNodes){
            if(node==null)
                continue;
            list.add(new Entry<>((K) node.key, (V) node.value));
            while(node.next!=null){
                node = node.next;
                list.add(new Entry<>((K)node.key,(V) node.value));
            }
        }
        return list;
    }

    V remove(K key){
        Node removingNode = firstNodes[key.hashCode()%capacity];
        if(removingNode==null){
            return null;
        }
        if(removingNode.key.equals(key)){
            firstNodes[key.hashCode()%capacity] = removingNode.next;
            return (V) removingNode.value;
        }
        while(true){
            if(removingNode.next==null){
                return null;
            }
            if(removingNode.next.key.equals(key)){
                V returningNodeValue = (V)removingNode.next.value;
                removingNode.next = removingNode.next.next;
                removingNode.next.next=null;
                return returningNodeValue;
            }
            else{
                    removingNode = removingNode.next;
                }
        }
    }

    class Node<k,v>{
        K key;
        V value;
        Node next;

        Node(K key,V value){
            this.key = key;
            this.value = value;
            next = null;
        }
    }

    class Entry<k,v>{
        private K key;
        private V value;

        public Entry(K key, V value) {
            this.key = key;
            this.value = value;
        }

        public K getKey() {
            return key;
        }

        public V getValue() {
            return value;
        }

        @Override
        public String toString() {
            return "Entry{" +
                    "key=" + key +
                    ", value=" + value +
                    "}\n";
        }
    }

}