Singly linked list basic code

I develope the linked list presuming that I need to change the `link` and `data` fields of Node class frequently to solve the questions available on geeksForGeeks.

The advisable way to implement the linkedlist class as a Java Professional is given here and here .



class Node{
private Object data;
private Node link;


Node(){
this.data=0;
this.link=null;
}

Node(Object data){
this.data=data;
this.link=null;
}

Node(Object data,Node link){
this.data=data;
this.link=link;
}

void setData(Object data){
this.data=data;
}
void setLink(Node link){
this.link=link;
}

Object getData(){
return data;
}
Node getLink(){
return link;
}


}

class MyLinkedList{

public Node head;


MyLinkedList(){
head=null;
}

public void add(Object data){
Node p=new Node(data,null);
if(head==null){
head=p;
}
else{
(linkToLastNode()).setLink(p);
}

}

public void addFirst(Object data){
Node p=new Node(data,head);
if(head==null){
head=p;
}
else{

head =p;
}

}

public Object deleteFirst(){
Object data=head.getData();
head=head.getLink();
return data;
}


private Node linkToLastNode(){
if(head==null){
return null;
}
else{
Node temp=head;
while((temp.getLink())!=null){
temp=temp.getLink();
}
return temp;
}
}

public String toString(){
Node temp= head;
if(temp==null){
return "";
}
else{
StringBuilder sb=new StringBuilder(" ") ;
while(temp!=null){
sb.append(temp.getData());
sb.append(" ");
temp=temp.getLink();
}
return sb.toString();
}
}


}