Added support in Gson for serializing/deserializing from primitive char.

Created a new class for character/char tests, PrimitiveCharacterTest. This is the start of breaking down PrimitiveTest into smaller chunks.
When MiniGson can not find a type adapter for a type, revised the message to say can't handle instead of can't serialize.

gson/src/main/java/com/google/gson/DefaultTypeAdapters.java

@@ -75,6 +75,7 @@ final class DefaultTypeAdapters {
     map.register(GregorianCalendar.class, GREGORIAN_CALENDAR_TYPE_ADAPTER, true);
 
     // Add primitive serializers
+    map.register(char.class, CHARACTER_TYPE_ADAPTER, true);
     map.register(Character.class, CHARACTER_TYPE_ADAPTER, true);
     map.register(Number.class, NUMBER_TYPE_ADAPTER, true);
 
@@ -93,6 +94,7 @@ final class DefaultTypeAdapters {
     map.register(GregorianCalendar.class, GREGORIAN_CALENDAR_TYPE_ADAPTER, true);
 
     // Add primitive deserializers
+    map.register(char.class, wrapDeserializer(CHARACTER_TYPE_ADAPTER), true);
     map.register(Character.class, wrapDeserializer(CHARACTER_TYPE_ADAPTER), true);
     map.register(Number.class, NUMBER_TYPE_ADAPTER, true);
 

gson/src/main/java/com/google/gson/internal/bind/MiniGson.java

@@ -95,7 +95,7 @@ public final class MiniGson {
           return candidate;
         }
       }
-      throw new IllegalArgumentException("This MiniGSON cannot serialize " + type);
+      throw new IllegalArgumentException("This MiniGSON cannot handle " + type);
     } finally {
       threadCalls.remove(type);
     }

gson/src/test/java/com/google/gson/functional/PrimitiveCharacterTest.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2008 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.gson.functional;
+
+import junit.framework.TestCase;
+
+import com.google.gson.Gson;
+
+/**
+ * Functional tests for Java Character values.
+ *
+ * @author Inderjeet Singh
+ * @author Joel Leitch
+ */
+public class PrimitiveCharacterTest extends TestCase {
+  private Gson gson;
+
+  @Override
+  protected void setUp() throws Exception {
+    super.setUp();
+    gson = new Gson();
+  }
+
+  public void testPrimitiveCharacterAutoboxedSerialization() {
+    assertEquals("\"A\"", gson.toJson('A'));
+    assertEquals("\"A\"", gson.toJson('A', char.class));
+    assertEquals("\"A\"", gson.toJson('A', Character.class));
+  }
+
+  public void testPrimitiveCharacterAutoboxedDeserialization() {
+    char expected = 'a';
+    char actual = gson.fromJson("a", char.class);
+    assertEquals(expected, actual);
+
+    actual = gson.fromJson("\"a\"", char.class);
+    assertEquals(expected, actual);
+
+    actual = gson.fromJson("a", Character.class);
+    assertEquals(expected, actual);
+  }
+}