Fix the minor issue on the sample1

Author: erafaelmanuel

core/src/main/java/io/ermdev/mapfierj/Converter.java

@@ -228,13 +228,13 @@ public <T> T convert() throws MappingException {
 
     protected class Objects {
 
-        Object object;
+        volatile Object object;
 
-        public Object getObject() {
+        public synchronized Object getObject() {
             return object;
         }
 
-        public void setObject(Object object) {
+        public synchronized void setObject(Object object) {
             this.object = object;
         }
     }

sample/src/main/java/io/ermdev/mapfierj/sample/sample1/IntegerCarConverter.java

@@ -10,16 +10,20 @@ public class IntegerCarConverter extends TypeConverterAdapter<Integer, Car> {
     private CarRepository carRepository;
 
     public IntegerCarConverter() {
+        carRepository = new CarRepository();
     }
 
     public IntegerCarConverter(CarRepository carRepository) {
         this.carRepository = carRepository;
     }
 
-
     @Override
     public Car convertTo(Integer o) throws TypeException {
-        return carRepository.getById(o);
+        try {
+            return carRepository.getById(o);
+        } catch (NullPointerException e) {
+            return null;
+        }
     }
 
     @Override

sample/src/main/java/io/ermdev/mapfierj/sample/sample1/Sample1.java

@@ -11,8 +11,8 @@ public class Sample1 {
 
     @Test
     public void modelMapper() {
-        final String PACKAGE_NAME = getClass().getPackage().toString();
-        int carId = (int) (Math.random() * 10) + 1;
+        final String PACKAGE_NAME = "io.ermdev.mapfierj.sample.sample1";
+        int carId = (int) (Math.random() * 8) + 1;
 
         ModelMapper mapper = new ModelMapper();
         mapper.getConverter().scanPackages(PACKAGE_NAME);

sample/src/main/java/io/ermdev/mapfierj/sample/sample2/IntegerCarConverter.java

@@ -2,6 +2,7 @@
 
 import io.ermdev.mapfierj.ConvertTo;
 import io.ermdev.mapfierj.FieldName;
+import io.ermdev.mapfierj.sample.sample1.IntegerCarConverter;
 
 public class Person {