improvement: avoid null pointers && fix: Method naming case problem

jdbc-template/src/main/java/guru/springframework/jdbctemplate/employee/EmployeeRepository.java

@@ -76,7 +76,7 @@ public void save(Employee employee) {
    * @param employee the employee to be created
    * @return the id of the created employee.
    */
-  public long saveAndReturnId(Employee employee) {
+  public Long saveAndReturnId(Employee employee) {
     String sqlQuery = "insert into employees(first_name, last_name, yearly_income) " +
                       "values (?, ?, ?)";
 
@@ -90,7 +90,11 @@ public long saveAndReturnId(Employee employee) {
       return stmt;
     }, keyHolder);
 
-    return keyHolder.getKey().longValue();
+    if (keyHolder.getKey() != null) {
+      return keyHolder.getKey().longValue();
+    }else {
+      return  null;
+    }
   }
 
 

testingspringbootrestfulservice/src/main/java/com/springframeworkguru/Controller/ProductController.java

@@ -33,7 +33,7 @@ public ResponseEntity<List<Product>> getAllProducts(){
 
     @GetMapping("product/{id}")
     public ResponseEntity<Product> getProductById(@PathVariable("id") int id){
-        return new ResponseEntity<>(productService.getProductByid(id),HttpStatus.OK);
+        return new ResponseEntity<>(productService.getProductById(id),HttpStatus.OK);
     }
 
     @DeleteMapping("product/{id}")

testingspringbootrestfulservice/src/main/java/com/springframeworkguru/Service/ProductService.java

@@ -9,7 +9,7 @@ public interface ProductService {
 
      Product addProduct(Product product) throws ProductAlreadyExistsException;
     List<Product> getAllProducts();
-     Product getProductByid(int id);
+     Product getProductById(int id);
     Product deleteProductById(int id);
 
 

testingspringbootrestfulservice/src/main/java/com/springframeworkguru/Service/ProductServiceImpl.java

@@ -35,7 +35,7 @@ public List<Product> getAllProducts() {
     }
 
     @Override
-    public Product getProductByid(int id) {
+    public Product getProductById(int id) {
         return productRepository.findById(id).orElse(null);
     }