Inlined releaseInstance methods

RISE-V2G-EVCC/src/main/java/com/v2gclarity/risev2g/evcc/transportLayer/TCPClient.java

@@ -139,7 +139,7 @@ public class TCPClient extends StatefulTransportLayerClient {
 				getInStream().close();
 				getOutStream().close();
 				getTcpSocketToServer().close();
-				releaseInstance();
+				uniqueTCPClientInstance = null;
 				Thread.currentThread().interrupt();
 			} catch (IOException e) {
 				getLogger().error("Error occurred while trying to close TCP socket to server", e);
@@ -149,10 +149,6 @@ public class TCPClient extends StatefulTransportLayerClient {
 		}
 	}
 	
-	private static void releaseInstance() {
-		uniqueTCPClientInstance = null;
-	}
-	
 	public Socket getTcpSocketToServer() {
 		return tcpSocketToServer;
 	}

RISE-V2G-EVCC/src/main/java/com/v2gclarity/risev2g/evcc/transportLayer/TLSClient.java

@@ -211,7 +211,7 @@ public class TLSClient extends StatefulTransportLayerClient {
 				getInStream().close();
 				getOutStream().close();
 				getTlsSocketToServer().close();
-				releaseInstance();
+				uniqueTLSClientInstance = null;
 				Thread.currentThread().interrupt();
 			} catch (IOException e) {
 				getLogger().error("Error occurred while trying to close TCP socket to server", e);
@@ -221,10 +221,6 @@ public class TLSClient extends StatefulTransportLayerClient {
 		}
 	}
 	
-	private static void releaseInstance() {
-		uniqueTLSClientInstance = null;
-	}
-	
 	
 	public SSLSocket getTlsSocketToServer() {
 		return tlsSocketToServer;

RISE-V2G-EVCC/src/main/java/com/v2gclarity/risev2g/evcc/transportLayer/UDPClient.java

@@ -105,13 +105,9 @@ public class UDPClient {
 	}
 	
 
-	public static UDPClient getInstance() {
+	public static synchronized UDPClient getInstance() {
 		if (uniqueUDPClientInstance == null) {
-			synchronized (UDPClient.class) {
-				if (uniqueUDPClientInstance == null) {
-					uniqueUDPClientInstance = new UDPClient();
-				}
-			}
+			uniqueUDPClientInstance = new UDPClient();
 		}
 		return uniqueUDPClientInstance;
 	}
@@ -151,10 +147,6 @@ public class UDPClient {
 	public void stop() {
 		getSocketToUDPServer().close();
 		getLogger().debug("UDP client stopped");
-		releaseInstance();
-	}
-	
-	private static void releaseInstance() {
 		uniqueUDPClientInstance = null;
 	}