Question: I want to increase the Line2D width. I could not find any method to do that. Do I need to actually make a small rectangle for this purpose?

Answer: 
You should use `setStroke` to set a stroke of the `Graphics2D` object.

The example at [http://www.java2s.com](http://www.java2s.com/Code/JavaAPI/java.awt/Graphics2DsetStrokeStrokes.htm) gives you some code examples.

The following code produces the image below:

```
import java.awt.*;
import java.awt.geom.Line2D;
import javax.swing.*;

public class FrameTest {
    public static void main(String[] args) {
        JFrame jf = new JFrame("Demo");
        Container cp = jf.getContentPane();
        cp.add(new JComponent() {
            public void paintComponent(Graphics g) {
                Graphics2D g2 = (Graphics2D) g;
                g2.setStroke(new BasicStroke(10));
                g2.draw(new Line2D.Float(30, 20, 80, 90));
            }
        });
        jf.setSize(300, 200);
        jf.setVisible(true);
    }
}

```

![enter image description here](https://i.stack.imgur.com/LB7kF.png)

(Note that the `setStroke` method is not available in the `Graphics` object. You have to cast it to a `Graphics2D` object.)

---

This post has been rewritten as an article [here](http://programming.guide/java/increasing-line-width.html).
What is `Stroke`:

> 
> The BasicStroke class defines a basic set of rendering attributes for
>  the outlines of graphics primitives, which are rendered with a
>  Graphics2D object that has its Stroke attribute set to this
>  BasicStroke.
> 
> 
> 

<https://docs.oracle.com/javase/7/docs/api/java/awt/BasicStroke.html>

Note that the `Stroke` setting:

```
Graphics2D g2 = (Graphics2D) g;
g2.setStroke(new BasicStroke(10));

```

is setting the line width,since `BasicStroke(float width)`:

> 
> Constructs a solid BasicStroke with the specified line width and with default values for the cap and join styles.
> 
> 
> 

And, it also effects other methods like `Graphics2D.drawLine(int x1, int y1, int x2, int y2)` and `Graphics2D.drawRect(int x, int y, int width, int height)`:

> 
> The methods of the Graphics2D interface that use the outline Shape
>  returned by a Stroke object include draw and any other methods that
>  are implemented in terms of that method, such as drawLine, drawRect,
>  drawRoundRect, drawOval, drawArc, drawPolyline, and drawPolygon.
> 
> 
>