diff --git a/src/main/java/it/unibz/inf/isochrone/algorithm/Isochrone.java b/src/main/java/it/unibz/inf/isochrone/algorithm/Isochrone.java
index a7876b6d3a266d0609beb2bef97f346fe28c7a9b..d66d30b75549eea2c6c232714804c7ec85259bc1 100644
--- a/src/main/java/it/unibz/inf/isochrone/algorithm/Isochrone.java
+++ b/src/main/java/it/unibz/inf/isochrone/algorithm/Isochrone.java
@@ -134,7 +134,7 @@ public abstract class Isochrone {
 			for (final Link link : adjacents) {
 				if (link.isContinuous()) {
 					updateQueue(expandContinuousLink(node, link));
-					if (new Double(Double.MIN_VALUE).equals(link.getStartOffset())) {
+					if (Double.valueOf(Double.MIN_VALUE).equals(link.getStartOffset())) {
 						output.addLink(link);
 					}
 				} else {
diff --git a/src/main/java/it/unibz/inf/isochrone/config/ConfigIsochrone.java b/src/main/java/it/unibz/inf/isochrone/config/ConfigIsochrone.java
index 7c8b08638798ecaef17e12baabf058c118b8e0d7..f75dbb65c8a8d87a87f91ee5a71074f075f038c9 100644
--- a/src/main/java/it/unibz/inf/isochrone/config/ConfigIsochrone.java
+++ b/src/main/java/it/unibz/inf/isochrone/config/ConfigIsochrone.java
@@ -69,16 +69,12 @@ public final class ConfigIsochrone {
 	@PropertyValue("org.postgresql.username")
 	private String user;
 
-	public static ConfigIsochrone getInstance() {
-		if (instance == null) { // avoid sync penalty if we can
-			synchronized (ConfigIsochrone.class) {
-				if (instance == null) { // lock has to be inside of synchronized block
-					final ConfigIsochrone config = new ConfigBuilder<>(ConfigIsochrone.class).build();
-					config.initConnectionFactory();
-
-					instance = config;
-				}
-			}
+	public static synchronized ConfigIsochrone getInstance() {
+		if (instance == null) {
+			final ConfigIsochrone config = new ConfigBuilder<>(ConfigIsochrone.class).build();
+			config.initConnectionFactory();
+
+			instance = config;
 		}
 
 		return instance;
diff --git a/src/main/java/it/unibz/inf/isochrone/network/Location.java b/src/main/java/it/unibz/inf/isochrone/network/Location.java
index 3c1ef528b47bda4f371b7b18e8a2c148df835b42..a82ad365cf0b020a4856e7607504acf5410ac49a 100644
--- a/src/main/java/it/unibz/inf/isochrone/network/Location.java
+++ b/src/main/java/it/unibz/inf/isochrone/network/Location.java
@@ -39,7 +39,7 @@ public class Location {
 		}
 
 		final Location other = (Location) obj;
-		return other.getLinkId() == getLinkId() && new Double(other.getOffset()).equals(getOffset());
+		return other.getLinkId() == getLinkId() && Double.valueOf(other.getOffset()).equals(getOffset());
 	}
 
 	@Override