refactoring Student class grade field

core-java-modules/core-java-lang-oop-2/src/main/java/com/baeldung/accessmodifiers/publicmodifier/Student.java

@@ -4,19 +4,21 @@ import java.math.BigDecimal;
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
+import java.util.Date;
 
 public class Student {
 
-    private BigDecimal grade; //new representation
+    private StudentGrade grade; //new data representation
+//    private int grade; //old data representation
     private String name;   
     private int age;
     
-    public int getGrade() {
+    public void setGrade(int grade) {        
-        return grade.intValue(); //Backward compatibility
+        this.grade = new StudentGrade(grade);
     }
 
-    public BigDecimal getBigDecimalGrade() {
+    public int getGrade() {
-        return grade;
+        return this.grade.getGrade().intValue(); //int is returned for backward compatibility
     }
     
     public Connection getConnection() throws SQLException {
@@ -43,4 +45,23 @@ public class Student {
         return this.name;
     }
 
+    private class StudentGrade {
+        private BigDecimal grade = BigDecimal.ZERO;
+        private Date updatedAt;
+        
+        public StudentGrade(int grade) {
+            this.grade = new BigDecimal(grade);
+            this.updatedAt = new Date();
+        }
+        
+        public BigDecimal getGrade() {
+            return grade;
+        }
+        
+        public Date getDate() {
+            return updatedAt;
+        }
+        
+     }
+    
 }