Added synchronized to methods

src/main/java/org/gcube/gcat/persistence/ckan/CKANUserCache.java

@@ -40,7 +40,7 @@ public abstract class CKANUserCache {
 	private CKANUserCache() {
 	}
 	
-	public static CKANUser getCurrrentCKANUser() {
+	public synchronized static CKANUser getCurrrentCKANUser() {
 		SecretManager secretManager = SecretManagerProvider.instance.get();
 		String context = secretManager.getContext();
 		Cache<String,CKANUser> userCache = userCachePerContext.get(context);
@@ -59,7 +59,7 @@ public abstract class CKANUserCache {
 		return ckanUser;
 	}
 	
-	public static void removeUserFromCache() {
+	public synchronized static void removeUserFromCache() {
 		SecretManager secretManager = SecretManagerProvider.instance.get();
 		String context = secretManager.getContext();
 		Cache<String,CKANUser> userCache = userCachePerContext.get(context);