src/java.desktop/windows/classes/sun/awt/windows/WWindowPeer.java

*** 78,87 ****
--- 78,89 ----
      /*
       * Called (on the Toolkit thread) before the appropriate
       * WindowStateEvent is posted to the EventQueue.
       */
      private WindowListener windowListener;
+     private float scaleX;
+     private float scaleY;
  
      /**
       * Initialize JNI field IDs
       */
      private static native void initIDs();
*** 188,198 ****
              ((Window) target).setBackground(SystemColor.window);
          }
  
          // Express our interest in display changes
          GraphicsConfiguration gc = getGraphicsConfiguration();
!         ((Win32GraphicsDevice)gc.getDevice()).addDisplayChangedListener(this);
  
          initActiveWindowsTracking((Window)target);
  
          updateIconImages();
  
--- 190,203 ----
              ((Window) target).setBackground(SystemColor.window);
          }
  
          // Express our interest in display changes
          GraphicsConfiguration gc = getGraphicsConfiguration();
!         Win32GraphicsDevice gd = (Win32GraphicsDevice) gc.getDevice();
!         gd.addDisplayChangedListener(this);
!         scaleX = gd.getDefaultScaleX();
!         scaleY = gd.getDefaultScaleY();
  
          initActiveWindowsTracking((Window)target);
  
          updateIconImages();
  
*** 537,546 ****
--- 542,564 ----
              newDev.addDisplayChangedListener(this);
          }
  
          AWTAccessor.getComponentAccessor().
              setGraphicsConfiguration((Component)target, winGraphicsConfig);
+ 
+         checkDPIChange(newDev);
+     }
+ 
+     private void checkDPIChange(Win32GraphicsDevice newDev) {
+         float newScaleX = newDev.getDefaultScaleX();
+         float newScaleY = newDev.getDefaultScaleY();
+ 
+         if (scaleX != newScaleX || scaleY != newScaleY) {
+             windowDPIChange(scaleX, scaleY, newScaleX, newScaleY);
+             scaleX = newScaleX;
+             scaleY = newScaleY;
+         }
      }
  
      /**
       * From the DisplayChangedListener interface.
       *
*** 779,788 ****
--- 797,809 ----
                  log.finer("Translucent window painter is null in updateWindow");
              }
          }
      }
  
+     native void windowDPIChange(float prevScaleX, float prevScaleY,
+                                 float newScaleX, float newScaleY);
+ 
      /*
       * The method maps the list of the active windows to the window's AppContext,
       * then the method registers ActiveWindowListener, GuiDisposedListener listeners;
       * it executes the initilialization only once per AppContext.
       */