I am not sure where to put my if statements? need help getting things straight

I am not sure where to put my if statements because I get an error when in the constructor and I'm not sure where else to put them.

import java.awt.Color;

/**
* Create a class called GrowingDot. This will draw a circle on the screen
* in a specified color. Every time it is drawn it will increase 
* in size until it reaches a maximum size and then it will be reset
* to its minimum size and start growing again.
* 
* The class will need 4 class variables. Declare 3 ints (the x, y location
* of the circle and the size of the circle). 
* The class will also need a Color variable to store the circle's color.
* 
* Create a Constructor that takes two ints and a Color object as 
* parameters. These represent the x, y coordinates of the circle 
* (in that order) and its color. Use the parameters to set the 
* appropriate class variables.
* 
* If the x parameter is less than 0, set the class's variable to 0.
* Otherwise, use the value of the parameter. The same should be done
* with the y parameter.
* 
* If the Color object is null, set the class's variable to red.
* Otherwise, use the value of the parameter.
* 
* For the size of the circle, it should start off at 5.
* 
* Create a getX method that returns an int and takes no parameters. This
* should return the x coordinate of the circle.
* 
* Create a getY method that returns an int and takes no parameters. This
* should return the y coordinate of the circle.
* 
* Create a getColor method that returns a Color and takes no parameters.
* This should return the color of the circle.
* 
* Create a setPosition method that takes two int parameters (the x, y 
* coordinates) and returns nothing. If the x parameter is greater than 
* or equal to 0, update the class's variable to the parameter's value. 
* Otherwise, do nothing. Do the same with the y parameter.
* 
* Create a display method that takes a Graphics object as its parameter and
* returns nothing. Using the Graphics object draw a filled oval using 
* the class's size variable for its dimensions and the Color variable 
* for the color. Use the class's x, y variables as
* the coordinates for the circle.
* 
* After the circle has been drawn, increase the size variable by 1. If the
* new size is greater than 10, change it to 5.  
* 
* Make sure you format it and include the needed documentation.
*/

public class GrowingDot {

    int x;
    int y;
    int location;
    Color c;

    public GrowingDot(int x1, int y1, Color color) {
        x = x1;
        y = y1;
        c = color;

        if (x1 < 0) {
            return x = 0;
                return x1;
        }

        if (y1 < 0) {
            return y = 0;
                return y1;
        }

        if (color = null) {
            return c = red;
                return color;
        }
        }    
    }
}