Point in Polygon or not test

I try to Programm a Java Application, which print out if a Mouse given Point is inside or outside a given Polygon. But I don´t know how to work with the public boolean contains Methode. Can somebody help me? My arrays arrx and arry saved the coordinates of the Poly, but how I could say that he have to check out if there is a Point in or out of my poly.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class PiP extends JPanel implements MouseListener,MouseMotionListener  {
int x0,x1,y0,y1,i = 0,z = 1; 
int [][] pkt;
boolean zeichnen;
int []points = new int[100];
double y;
public static void main(String[] args) {
PiP p= new PiP();
}
public PiP() {
  JFrame fenster = new JFrame("Fenster");
  fenster.setBounds(0,0,600,600);
  fenster.setVisible(true);
  fenster.add(this); 
  fenster.addMouseListener(this);
  fenster.addMouseMotionListener(this);
  fenster.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}  

public void mousePressed(MouseEvent e) {          //if mouse pressed
  pkt = new int[z][4]; 
  zeichnen = true;
  x1 = e.getX();
  y1 = e.getY();    
  pkt[i][0] = x1;
  pkt[i][1] = y1;
  System.out.println("x = "+pkt[i][0]+" und"+" y = "+pkt[i][1]);
  repaint();
  i++;
  z++;
}
public void Polygon(int arrx, int arry){
return arrx;
}
public boolean contains(int x1,int y1){     //here I tried to use contains, but I am 
return true;                                 //not sure how to take the variables from 
}                                           //the polygon to test if the Points are in
else {                                      //the Polygon
 return false;
}
}
public void mouseClicked(MouseEvent e) { }
public void mouseReleased(MouseEvent e) { }
public void mouseMoved(MouseEvent e) { }
public void mouseDragged(MouseEvent e) { }
public void mouseEntered(MouseEvent e) { }
public void mouseExited(MouseEvent e) { }
public void paint(Graphics g) {
    g.setColor(Color.RED);
int []arrx = {163,123,81,163,293,332,426,461,493,491,383,328,313,263};     //Poly x coordinates
int []arry = {143,219,359,433,478,523,448,401,306,238,219,205,168,158};   //Poly y coordinates
    g.drawPolygon(arrx,arry,arrx.length);
    if (zeichnen) {
     g.drawRect(x1,y1,10,10);
    g.fillRect(x1,y1,10,10);  
    } // end of if
  }
  }