Convert nine variable assignments to the usage of compound operators

[elfring]

:eyes: Some source code analysis tools can help to find opportunities for improving software components. :thought_balloon: I propose to increase the usage of compound operators accordingly.

diff --git a/structr-core/src/main/java/org/structr/core/property/IntegerSumProperty.java b/structr-core/src/main/java/org/structr/core/property/IntegerSumProperty.java
index b5a1029783..7ca529f4c4 100644
--- a/structr-core/src/main/java/org/structr/core/property/IntegerSumProperty.java
+++ b/structr-core/src/main/java/org/structr/core/property/IntegerSumProperty.java
@@ -72,7 +72,7 @@ public class IntegerSumProperty extends AbstractReadOnlyProperty<Integer> {
 
 			if (value != null) {
 
-				sum = sum + value.intValue();
+				sum += value.intValue();
 			}
 		}
 
diff --git a/structr-core/src/main/java/org/structr/schema/SchemaHelper.java b/structr-core/src/main/java/org/structr/schema/SchemaHelper.java
index a61776a669..458d8c243c 100644
--- a/structr-core/src/main/java/org/structr/schema/SchemaHelper.java
+++ b/structr-core/src/main/java/org/structr/schema/SchemaHelper.java
@@ -897,7 +897,7 @@ public class SchemaHelper {
 				if (propertyNames.contains(propertyName)) {
 
 					while (propertyNames.contains(propertyName)) {
-						propertyName = propertyName + count++;
+						propertyName += count++;
 					}
 
 					logger.warn("Property name {} already present in type {}, renaming to {}", oldName, entity.getClassName(), propertyName);
diff --git a/structr-rest/src/main/java/org/structr/rest/maintenance/SnapshotCommand.java b/structr-rest/src/main/java/org/structr/rest/maintenance/SnapshotCommand.java
index de96cee14c..a9f0efaf34 100644
--- a/structr-rest/src/main/java/org/structr/rest/maintenance/SnapshotCommand.java
+++ b/structr-rest/src/main/java/org/structr/rest/maintenance/SnapshotCommand.java
@@ -279,7 +279,7 @@ public class SnapshotCommand extends NodeServiceCommand implements MaintenanceCo
 
 		// append JSON extension
 		if (!fileName.endsWith(".json")) {
-			fileName = fileName + ".json";
+			fileName += ".json";
 		}
 
 		// create
diff --git a/structr-rest/src/main/java/org/structr/rest/resource/LogResource.java b/structr-rest/src/main/java/org/structr/rest/resource/LogResource.java
index 0f14cd3c0f..27ac819890 100644
--- a/structr-rest/src/main/java/org/structr/rest/resource/LogResource.java
+++ b/structr-rest/src/main/java/org/structr/rest/resource/LogResource.java
@@ -693,7 +693,7 @@ public class LogResource extends Resource {
 			if (count == null) {
 				count = 1;
 			} else {
-				count = count + 1;
+				count += 1;
 			}
 			obj.put(totalProperty.jsonName(), count);
 
@@ -710,7 +710,7 @@ public class LogResource extends Resource {
 					if (c == null) {
 						c = multiplier;
 					} else {
-						c = c + multiplier;
+						c += multiplier;
 					}
 
 					obj.put(key, c);
@@ -743,7 +743,7 @@ public class LogResource extends Resource {
 			if (count == null) {
 				count = 1;
 			} else {
-				count = count + 1;
+				count += 1;
 			}
 			obj.put(totalProperty.jsonName(), count);
 
@@ -759,7 +759,7 @@ public class LogResource extends Resource {
 				if (c == null) {
 					c = multiplier;
 				} else {
-					c = c + multiplier;
+					c += multiplier;
 				}
 
 				obj.put(key, c);
diff --git a/structr-ui/src/main/java/org/structr/web/auth/UiAuthenticator.java b/structr-ui/src/main/java/org/structr/web/auth/UiAuthenticator.java
index db3465998f..bda1d825dc 100644
--- a/structr-ui/src/main/java/org/structr/web/auth/UiAuthenticator.java
+++ b/structr-ui/src/main/java/org/structr/web/auth/UiAuthenticator.java
@@ -243,7 +243,7 @@ public class UiAuthenticator implements Authenticator {
 				if (securityContext.isReadable(grant, false, false)) {
 
 					grantsFound++;
-					combinedFlags = combinedFlags | grant.getFlags();
+					combinedFlags |= grant.getFlags();
 				}
 			}
 		}
diff --git a/structr-ui/src/main/java/org/structr/web/entity/MinifiedCssFile.java b/structr-ui/src/main/java/org/structr/web/entity/MinifiedCssFile.java
index 57892abebb..b6063265c7 100644
--- a/structr-ui/src/main/java/org/structr/web/entity/MinifiedCssFile.java
+++ b/structr-ui/src/main/java/org/structr/web/entity/MinifiedCssFile.java
@@ -272,7 +272,7 @@ public interface MinifiedCssFile extends AbstractMinifiedFile {
 				if (token.endsWith("\\")) {
 					preservedTokens.add("\\");
 					css = css.replace(placeholder,  "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.size() - 1) + "___");
-					i = i + 1; // attn: advancing the loop
+					i += 1; // attn: advancing the loop
 					preservedTokens.add("");
 					css = css.replace("___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + i + "___",  "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.size() - 1) + "___");
 					continue;