Thread: can't compare class fields

hi ! There two classes
Node.java
DataPacket.java
The problem is I can't compare the field of the passed object "dp" with the field of the stored dataPacket, data packets are stored in the ArrayList "dataPackets". At the end I add also the full code for the Node class.

the Node.java contains the following method

public void acceptDPacket(DataPacket dp){
		boolean packetHere;
		for (int j = 0; j < dataPackets.size(); j++) {
			if (dp.getSeqNo() = dataPackets[j].getSeqNo()){
				packetHere = true;
				break;
			}
		}
		if (packetHere = true){
 
		} else dataPackets.add(dp);
	}

public class DataPacket {
 
	private Node dest;
	private Node source;
	private int seqNo;
	private String content;
 
	public DataPacket(String cont, Node dest, Node src) {
		this.content = cont;
		this.dest = dest;
		this.source = src;
 
	}
 
	public int getSeqNo(){
		return seqNo;
	}
 
	public String getContent(){
		return content;
	}
 
}

import java.util.ArrayList;
 
public class Node extends Thread{
 
	// constants initialization
	final int MAP_LENGTH = 1000;
	final int MAP_WIDTH = 1000;
 
	private int x = 0;
	private int y = 0;
	private int node_id;
	ArrayList<DataPacket> dataPackets = new ArrayList<DataPacket>();
 
	//node_id = thread's name
	public Node(String node_id) {
		super(node_id);
		this.x = (int) (MAP_LENGTH * Math.random());
		this.y = (int) (MAP_WIDTH * Math.random());
	}
 
	public void run(){
		System.out.println("Inside of node"+getNodeId()+" thread!");
	}
 
	public int getX() {
		return x;
	}
 
	public void setX(int x) {
		this.x = x;
	}
 
	public int getY() {
		return y;
	}
 
	public void setY(int y) {
		this.y = y;
	}
 
	public int getNodeId() {
		return this.node_id;
	}
 
	public void setNodeId(int nid){
		this.node_id = nid;
	}
 
	public void acceptDPacket(DataPacket dp){
		boolean packetHere;
		for (int j = 0; j < dataPackets.size(); j++) {
			if (dp.getSeqNo() = dataPackets[j].getSeqNo()){
				packetHere = true;
				break;
			}
		}
		if (packetHere = true){
 
		} else dataPackets.add(dp);
	}
 
}