Bugfix after issue #28

src/main/java/io/beanmapper/core/BeanField.java

@@ -6,6 +6,7 @@
 import io.beanmapper.core.inspector.PropertyAccessors;
 import io.beanmapper.exceptions.BeanMappingException;
 import io.beanmapper.exceptions.NoSuchPropertyException;
+import io.beanmapper.utils.DefaultValues;
 
 import java.util.Stack;
 
@@ -92,6 +93,10 @@ public Object writeObject(Object source, Object parent) throws BeanMappingExcept
                 getNext().writeObject(null, getCurrentField().getValue(parent));
             }
         } else {
+            if(source == null && getCurrentField().getType().isPrimitive()) {
+                // Primitives types can't be null.
+                source = DefaultValues.defaultValueFor(getCurrentField().getType());
+            }
             getCurrentField().setValue(parent, source);
         }
         return parent;

src/main/java/io/beanmapper/utils/DefaultValues.java

@@ -0,0 +1,24 @@
+package io.beanmapper.utils;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class DefaultValues {
+
+    static final Map<Class<?>,Object> defaultValues = new HashMap<Class<?>,Object>()
+    {{
+            put(boolean.class, false);
+            put(byte.class, (byte) 0);
+            put(short.class, (short) 0);
+            put(int.class, 0);
+            put(long.class, 0L);
+            put(char.class, '\0');
+            put(float.class, 0.0F);
+            put(double.class, 0.0);
+    }};
+
+    @SuppressWarnings("unchecked")
+    public static<T> T defaultValueFor(Class<T> clazz) {
+        return (T)defaultValues.get(clazz);
+    }
+}

src/test/java/io/beanmapper/BeanMapperTest.java

@@ -233,16 +233,20 @@ public void emptySource() {
         source.id = 42;
         source.name = "sourceName";
         source.emptyName = "notEmpty";
+        source.bool = true;
         EmptyTarget target = beanMapper.map(source, EmptyTarget.class);
         assertEquals(source.id, target.id, 0);
         assertEquals(source.name, target.name);
         assertEquals(source.emptyName, target.nestedEmptyClass.name);
+        assertEquals(source.bool, target.bool);
         // Test with empty source
         EmptySource emptySource = new EmptySource();
         EmptyTarget emptyTarget = beanMapper.map(emptySource, EmptyTarget.class);
-        assertNull(emptyTarget.id);
+        assertEquals(0, emptyTarget.id, 0); // Default for primitive int is 0
         assertNull(emptyTarget.name);
         assertNull(emptyTarget.nestedEmptyClass);
+        assertNull(emptyTarget.nestedEmpty);
+        assertEquals(false, emptyTarget.bool); // Default for primitive boolean is false
     }
 
     @Test
@@ -252,14 +256,16 @@ public void emptySourceToExistingTarget() {
         EmptyTarget existingTarget = new EmptyTarget();
         existingTarget.id = 42;
         existingTarget.name = "ExistingTargetName";
+        existingTarget.bool = true;
         existingTarget.nestedEmptyClass = new NestedEmptyTarget();
         existingTarget.nestedEmptyClass.name = "Hallo";
         existingTarget.nestedEmpty = new NestedEmptyTarget();
         existingTarget.nestedEmpty.name = "existingNestedTarget";
 
         EmptyTarget mappedTarget = beanMapper.map(source, existingTarget);
-        assertNull(mappedTarget.id);
+        assertEquals(0, mappedTarget.id, 0);// Default for primitive int is 0
         assertNull(mappedTarget.name);
+        assertEquals(false, mappedTarget.bool);// Default for primitive boolean is false
         assertNull(mappedTarget.nestedEmptyClass.name);
         assertNull(mappedTarget.nestedEmpty);
     }

src/test/java/io/beanmapper/testmodel/emptyobject/EmptySource.java

@@ -6,6 +6,7 @@ public class EmptySource {
 
     public Integer id;
     public String name;
+    public Boolean bool;
     @BeanProperty(name = "nestedEmptyClass.name")
     public String emptyName;
     public NestedEmptySource nestedEmpty;

src/test/java/io/beanmapper/testmodel/emptyobject/EmptyTarget.java

@@ -2,8 +2,9 @@
 
 public class EmptyTarget {
 
-    public Integer id;
+    public int id;
     public String name;
+    public boolean bool;
     public NestedEmptyTarget nestedEmptyClass;
     public NestedEmptyTarget nestedEmpty;
 }