Summary

The applications are blocked in a small method, even if they use the different BufferedImages and different threads.

Problem

When the graphics object is created for BufferedImage it will call:

GraphicsEnvironment env = GraphicsEnvironment.getLocalGraphicsEnvironment();
return env.createGraphics(this);

The problem is that getLocalGraphicsEnvironment() is a static and synchronized method.

Solution

Reimplement the method to not require synchronization and drop the "synchronized" keyword from the getLocalGraphicsEnvironment() method to reduce the overhead of the method in multi-core environments.

Specification

 java/awt/GraphicsEnvironment.java

 /**
  * Returns the local {@code GraphicsEnvironment}.
  * @return the local {@code GraphicsEnvironment}
  */
-public static synchronized GraphicsEnvironment getLocalGraphicsEnvironment() {
+public static GraphicsEnvironment getLocalGraphicsEnvironment() {