Move null check logic to separate method

Move null check logic to separate method

call-all-getters/src/main/java/com/baeldung/reflection/util/Utils.java

@@ -3,9 +3,10 @@ package com.baeldung.reflection.util;
 import java.beans.Introspector;
 import java.beans.PropertyDescriptor;
 import java.lang.reflect.Method;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
 
 import com.baeldung.reflection.model.Customer;
 
@@ -15,20 +16,28 @@ public class Utils {
         PropertyDescriptor[] propDescArr = Introspector.getBeanInfo(Customer.class, Object.class).getPropertyDescriptors();
         List<PropertyDescriptor>  propDescList = Arrays.asList(propDescArr);
         
-        List<String> nullProps = new ArrayList<String>();
+        List<String> nullProps = propDescList.stream()
-        
+                                        .filter(nulls(customer))
-        propDescList.stream().forEach(p -> {
+                                        .map(PropertyDescriptor::getName)
-            Method getterMethod = p.getReadMethod();
+                                        .collect(Collectors.toList());
-            try {
-                if (getterMethod != null && getterMethod.invoke(customer) == null) {
-                    // If the value if null for that field
-                    nullProps.add(p.getName());
-                }
-            } catch (Exception e) {
-                // Handle the exception
-                e.printStackTrace();
-            }
-        });
         return nullProps;
     }
+
+    private static Predicate<PropertyDescriptor> nulls(Customer customer) {
+        Predicate<PropertyDescriptor> isNull = new Predicate<PropertyDescriptor>() {
+            @Override
+            public boolean test(PropertyDescriptor pd) {
+                Method getterMethod = pd.getReadMethod();
+                boolean result = false;
+                try {
+                    result = (getterMethod != null && getterMethod.invoke(customer) == null);
+                } catch (Exception e) {
+                    // Handle the exception
+                    e.printStackTrace();
+                }
+                return result;
+            }
+        };
+        return isNull;
+    }
 }