fix: synchronized singleton getters

Author: c-dilks

common-tools/cnuphys/swimmer/src/main/java/cnuphys/lund/LundFileSupport.java

@@ -10,7 +10,7 @@ public class LundFileSupport {
 
 	private LundFileSupport() {}
 
-	public static LundFileSupport getInstance() {
+	public static synchronized LundFileSupport getInstance() {
 		if (instance == null) {
 			instance = new LundFileSupport();
 		}

common-tools/cnuphys/swimmer/src/main/java/cnuphys/lund/LundSupport.java

@@ -69,7 +69,7 @@ private LundSupport() {
 	 * 
 	 * @return the singleton object.
 	 */
-	public static LundSupport getInstance() {
+	public static synchronized LundSupport getInstance() {
 		if (instance == null) {
 			instance = new LundSupport();
 			instance.initStyles();