Client side is added

Client/src/main/java/hello/Message.java

@@ -0,0 +1,37 @@
+package hello;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+
+@JsonIgnoreProperties(ignoreUnknown = true)
+public class Message {
+
+    private long id;
+    private String content;
+
+    public Message() {
+    }
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getContent() {
+        return content;
+    }
+
+    public void setContent(String content) {
+        this.content = content;
+    }
+
+    @Override
+    public String toString() {
+        return "Message{" +
+                "id='" + id + '\'' +
+                ", content=" + content +
+                '}';
+    }
+}