Catch occasional NPE when setting tray icon.

src/main/java/org/qortal/gui/SysTray.java

@@ -291,19 +291,23 @@ public class SysTray {
 
 	public void setTrayIcon(int iconid) {
 		if (trayIcon != null) {
-			switch (iconid) {
-				case 1:
-					this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_syncing_time-alt.png"));
-					break;
-				case 2:
-					this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_minting.png"));
-					break;
-				case 3:
-					this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_syncing.png"));
-					break;
-				case 4:
-					this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_synced.png"));
-					break;
+			try {
+				switch (iconid) {
+					case 1:
+						this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_syncing_time-alt.png"));
+						break;
+					case 2:
+						this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_minting.png"));
+						break;
+					case 3:
+						this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_syncing.png"));
+						break;
+					case 4:
+						this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_synced.png"));
+						break;
+				}
+			} catch (NullPointerException e) {
+				LOGGER.info("Unable to set tray icon");
 			}
 		}
 	}