A pathfinding solution

Processing
13

hi sorry for the long silence, i dont have a lot of day off and i do programing in my free time.

i tried your solution guys but i have a problem and i cant manage it.

for now thats my code:

the world: (where i launch everything)

float currentSmallest = (parent.height * parent.height) + (parent.width * parent.width);
		float d;
		float target;
		for(int a = carn1m.size()-1; a >= 0; a--){
			for(int b = lac.size()-1; b >= 0; b--){
				Carnivor1M c1m = carn1m.get(a);
				Lac l = lac.get(b);
				d = ((c1m.position.x - l.position.x) * (c1m.position.x - l.position.x)) + ((c1m.position.y - l.position.y) * (c1m.position.y - l.position.y));
				
				
				if(d < currentSmallest){
					currentSmallest = d;
					target = currentSmallest;
					
					
					//c1m.arrive(target);
				}
			}
		}

my water source :

public class Lac {
	PApplet parent;
	
	ArrayList<PVector> lac;
	
	public PVector position;
	
	
	
	@SuppressWarnings("deprecation")
	public Lac(PApplet p,PVector l){
		
		lac = new ArrayList<PVector>();
		parent = p;
		position = l.get();
		
	}
	
	@SuppressWarnings("deprecation")
	public void add(PVector l){
		lac.add(l.get());
	}
	
	void update(){
		parent.stroke(1);
		parent.fill(0,182,210);
		parent.ellipse(position.x, position.y, 50, 50);
	}
	
	public void run(PApplet p){
		update();
	}
	
	public ArrayList<PVector> getLac(){
		return lac;
	}
}

and my creatur for the test :

public class Carnivor1M {
	PApplet parent;
	ArrayList<PVector> carn1m;
	
	public PVector position;
	DNA2 dna2;
	float xoff;
	float yoff;
	
	////////////variables genetiques
	float health;
	float r; ///la taille
	float maxspeed;
	
	int lastChildTime = -1;
	
	
	float maxforce;
	PVector acceleration;
	PVector velocity;
	
	@SuppressWarnings("deprecation")
	public Carnivor1M(PVector l, DNA2 dna2_, PApplet p){
		carn1m = new ArrayList<PVector>();
		
		parent = p;
		position = l.get();
		xoff = p.random(1000);
		yoff = p.random(1000);
		
		dna2 = dna2_;
		health = PApplet.map(dna2.genes[0], 0, 1, 50, 250);
		r = PApplet.map(dna2.genes[0], 0, 1, 10, 25);
		maxspeed = PApplet.map(dna2.genes[0], 0, 1, 10, 1);
		
		acceleration = new PVector(0,0);
		velocity = new PVector(0,0);
		maxforce = (float) 0.1;
		
	}
	
	void update(){
		float vx = PApplet.map(parent.noise(xoff), 0, 1, -maxspeed, maxspeed);
		float vy = PApplet.map(parent.noise(yoff), 0, 1, -maxspeed, maxspeed);
		PVector velocity = new PVector(vx,vy);
		xoff += 0.01;
		yoff += 0.01;
		position.add(velocity);
		//health -= 0.1;
	}
	
	void borders(PApplet p){
		if (position.x < -r) position.x = p.width+r;
	    if (position.y < -r) position.y = p.height+r;
	    if (position.x > p.width+r) position.x = -r;
	    if (position.y > p.height+r) position.y = -r;
	}
	
	void display(){
		parent.ellipseMode(PConstants.CENTER);
		parent.strokeWeight(2);
		parent.stroke(0,0,0, health);
		parent.fill(213, 0,0, health);
		parent.ellipse(position.x, position.y, r, r);
	}
	
	public DNA2 getDNA2(){
		return dna2;
	}
	
	public float getR(){
		return r;
	}
	
	public ArrayList<PVector> getCarnivor1M(){
		return carn1m;
	}
	
	public void run(PApplet p){
		update();
		borders(parent);
		display();
	}
	
	void applyForce(PVector force){
		acceleration.add(force);
	}
	
	public void arrive(PVector target){
		PVector desired = PVector.sub(target, position);
		float d = desired.mag();
		if(d < 100){
			float m = PApplet.map(d, 0, 100, 0, maxspeed);
			desired.setMag(m);
		}
		else{
			desired.setMag(maxspeed);
		}
		PVector steer = PVector.sub(desired, velocity);
		steer.limit(maxforce);
		applyForce(steer);
	}
	
}

so here is my problem: i need to turn the pythagorean theorem that jb4x explain to me into a PVector.
I have my float for the currentSmallest, the d and the target.
But when i launch c1m.arrive (my creature test) i need a PVector and not a float and i dont know how.

I think its not a good idea to change the creature or water source class, i tried and it come really mess up really fast.
can you help me find a solution ?

Thanks again for your times guys.