Merge branch 'refs/heads/1.3.1-SNAPSHOT' into 1.3.2-SNAPSHOT

# Conflicts:
#	workflow-engine-server/src/main/resources/convertorXML.bpmn

workflow-engine-core/src/main/java/cn/axzo/workflow/core/common/utils/BpmnJsonConverterUtil.java

@@ -438,7 +438,11 @@ public final class BpmnJsonConverterUtil {
                         tempEndNode.setId(END_EVENT_ID);
                     } else {
                         if (Objects.equals(defaultConditionConnectNode.getType(), NODE_EMPTY) && Objects.nonNull(defaultConditionConnectNode.getChildren())) {
-                            tempEndNode.setId(defaultConditionConnectNode.getChildren().getId());
+                            if (StringUtils.hasText(defaultConditionConnectNode.getChildren().getId())) {
+                                tempEndNode.setId(defaultConditionConnectNode.getChildren().getId());
+                            } else {
+                                tempEndNode.setId(END_EVENT_ID);
+                            }
                         } else {
                             tempEndNode.setId(defaultConditionConnectNode.getId());
                         }