Review fixes

Author: Sushisource

core/src/main/java/io/temporal/samples/workerversioning/Activities.java

@@ -1,5 +1,7 @@
 package io.temporal.samples.workerversioning;
 
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
 import io.temporal.activity.ActivityInterface;
 import io.temporal.activity.ActivityMethod;
 
@@ -13,30 +15,24 @@ public interface Activities {
   String someIncompatibleActivity(IncompatibleActivityInput input);
 
   class IncompatibleActivityInput {
-    String calledBy;
-    String moreData;
+    private final String calledBy;
+    private final String moreData;
 
-    public IncompatibleActivityInput() {}
-
-    public IncompatibleActivityInput(String calledBy, String moreData) {
+    @JsonCreator(mode = JsonCreator.Mode.PROPERTIES)
+    public IncompatibleActivityInput(
+        @JsonProperty("calledBy") String calledBy, @JsonProperty("moreData") String moreData) {
       this.calledBy = calledBy;
       this.moreData = moreData;
     }
 
+    @JsonProperty("calledBy")
     public String getCalledBy() {
       return calledBy;
     }
 
+    @JsonProperty("moreData")
     public String getMoreData() {
       return moreData;
     }
-
-    public void setCalledBy(String calledBy) {
-      this.calledBy = calledBy;
-    }
-
-    public void setMoreData(String moreData) {
-      this.moreData = moreData;
-    }
   }
 }

core/src/main/java/io/temporal/samples/workerversioning/README.md

@@ -9,7 +9,8 @@ The sample creates multiple worker versions (1.0, 1.1, and 2.0) within one deplo
 
 ## Steps to run this sample:
 
-1) Run a [Temporal service](https://github.com/temporalio/samples-java/tree/main/#how-to-use).
+1) Run a [Temporal service](https://github.com/temporalio/samples-java/tree/main/#how-to-use). And
+   ensure that you're using at least Server version 1.28.0 (CLI version 1.4.0).
 
 2) Start the main application (this will guide you through the sample):
     ```bash