Change REST API date responses to UTC for consistency

Author: tijsrademakers

Diff for: modules/flowable-common-rest/src/main/java/org/flowable/common/rest/util/DateToStringIso8601Serializer.java

@@ -26,7 +26,7 @@
 
 public class DateToStringSerializer extends JsonSerializer<Date> {
 
-    protected DateTimeFormatter isoFormatter = ISODateTimeFormat.dateTime();
+    protected DateTimeFormatter isoFormatter = ISODateTimeFormat.dateTime().withZoneUTC();
 
     @Override
     public void serialize(Date tmpDate, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException, JsonProcessingException {

Diff for: modules/flowable-common-rest/src/main/java/org/flowable/common/rest/util/DateToStringSerializer.java

@@ -15,7 +15,7 @@
 
 import java.util.Date;
 
-import org.flowable.common.rest.util.DateToStringIso8601Serializer;
+import org.flowable.common.rest.util.DateToStringSerializer;
 
 import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 
@@ -69,11 +69,11 @@ public class ExternalWorkerJobResponse {
     protected String exceptionMessage;
 
     @ApiModelProperty(value = "The due date for the job", example = "2021-05-04T16:35:10.474Z")
-    @JsonSerialize(using = DateToStringIso8601Serializer.class, as = Date.class)
+    @JsonSerialize(using = DateToStringSerializer.class, as = Date.class)
     protected Date dueDate;
 
     @ApiModelProperty(value = "The creation time of the job", example = "2020-05-04T16:35:10.474Z")
-    @JsonSerialize(using = DateToStringIso8601Serializer.class, as = Date.class)
+    @JsonSerialize(using = DateToStringSerializer.class, as = Date.class)
     protected Date createTime;
 
     @ApiModelProperty(value = "The tenant if of the job", example = "flowable")
@@ -83,7 +83,7 @@ public class ExternalWorkerJobResponse {
     protected String lockOwner;
 
     @ApiModelProperty(value = "The time when the lock expires", example = "2020-05-04T16:35:10.474Z")
-    @JsonSerialize(using = DateToStringIso8601Serializer.class, as = Date.class)
+    @JsonSerialize(using = DateToStringSerializer.class, as = Date.class)
     protected Date lockExpirationTime;
 
     public String getId() {