set seconds if set is called with a date

src/main/java/com/hellosign/sdk/resource/AbstractResource.java

@@ -66,7 +66,7 @@ protected boolean has(String key) {
     protected void set(String key, Object value) {
         try {
             if (value instanceof Date) {
-                dataObj.put(key, ((Date) value).getTime());
+                dataObj.put(key, ((Date) value).toInstant().getEpochSecond());
             } else {
                 dataObj.put(key, value);
             }

src/test/java/com/hellosign/sdk/AbstractResourceTest.java

@@ -0,0 +1,34 @@
+package com.hellosign.sdk;
+
+import static org.junit.Assert.assertEquals;
+
+import com.hellosign.sdk.resource.SignatureRequest;
+import java.util.Date;
+import org.json.JSONObject;
+import org.junit.Test;
+
+public class AbstractResourceTest {
+
+    @Test
+    public void testCreatedAt() throws HelloSignException {
+        JSONObject obj = new JSONObject("{\"signature_request\": {\"created_at\": 1644606159}}");
+        TestResource request = new TestResource(obj);
+        Date created_at = request.getCreatedAt();
+        long timestamp = created_at.getTime();
+
+        TestResource request2 = new TestResource();
+        request2.set(SignatureRequest.SIGREQ_CREATED_AT, 1644606159);
+        Date created_at2 = request2.getCreatedAt();
+        long timestamp2 = created_at2.getTime();
+
+        assertEquals(timestamp, timestamp2);
+
+        TestResource request3 = new TestResource();
+        Date date = new Date(1644606159 * 1000L);
+        request3.set(SignatureRequest.SIGREQ_CREATED_AT, date);
+        Date created_at3 = request3.getCreatedAt();
+        long timestamp3 = created_at3.getTime();
+
+        assertEquals(timestamp, timestamp3);
+    }
+}

src/test/java/com/hellosign/sdk/TestResource.java

@@ -0,0 +1,26 @@
+package com.hellosign.sdk;
+
+import com.hellosign.sdk.resource.AbstractResource;
+import com.hellosign.sdk.resource.SignatureRequest;
+import java.util.Date;
+import org.json.JSONObject;
+
+public class TestResource extends AbstractResource {
+
+    public TestResource() {
+        super();
+    }
+
+    public TestResource(JSONObject obj) throws HelloSignException {
+        super(obj, SignatureRequest.SIGREQ_KEY);
+    }
+
+    @Override
+    public void set(String key, Object value) {
+        super.set(key, value);
+    }
+
+    public Date getCreatedAt() {
+        return getDate(SignatureRequest.SIGREQ_CREATED_AT);
+    }
+}