Summary

The java.awt.image.BufferedImage class is not thread-safe, but one of its methods was marked as synchronized.

Problem

The method setRGB(int x, int y, int rgb) in BufferedImage is synchronized, but all other methods in this class are not. For example the similar methods:

setRGB(int startX, int startY, int w, int h, int[] rgbArray, int offset, int scansize) and get methods:
getRGB(int x, int y)
getRGB(int, int, int, int, int[], int, int).

Solution

The synchronized keyword should be removed.

Specification

src/java.desktop/share/classes/java/awt/image/BufferedImage.java:

    * @param y the Y coordinate of the pixel to set
    * @param rgb the RGB value
    * @see #getRGB(int, int)
    * @see #getRGB(int, int, int, int, int[], int, int)
    */
 -  public synchronized void setRGB(int x, int y, int rgb) {
 +  public void setRGB(int x, int y, int rgb) {
        raster.setDataElements(x, y, colorModel.getDataElements(rgb, null));
    }