Eliminating code overhead

* calculating size of the list once in case of loops, avoided creation of string builder object if the length type argument is 0
* replaced null check boilerplate code with nullSafe()

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

@@ -122,7 +122,7 @@ public enum FieldNamingPolicy implements FieldNamingStrategy {
    */
   static String separateCamelCase(String name, String separator) {
     StringBuilder translation = new StringBuilder();
-    for (int i = 0; i < name.length(); i++) {
+    for (int i = 0, length = name.length(); i < length; i++) {
       char character = name.charAt(i);
       if (Character.isUpperCase(character) && translation.length() != 0) {
         translation.append(separator);
@@ -139,8 +139,9 @@ public enum FieldNamingPolicy implements FieldNamingStrategy {
     StringBuilder fieldNameBuilder = new StringBuilder();
     int index = 0;
     char firstCharacter = name.charAt(index);
+    int length = name.length();
 
-    while (index < name.length() - 1) {
+    while (index < length - 1) {
       if (Character.isLetter(firstCharacter)) {
         break;
       }
@@ -149,7 +150,7 @@ public enum FieldNamingPolicy implements FieldNamingStrategy {
       firstCharacter = name.charAt(++index);
     }
 
-    if (index == name.length()) {
+    if (index == length) {
       return fieldNameBuilder.toString();
     }
 

gson/src/main/java/com/google/gson/internal/$Gson$Types.java

@@ -411,7 +411,7 @@ public final class $Gson$Types {
   }
 
   private static int indexOf(Object[] array, Object toFind) {
-    for (int i = 0; i < array.length; i++) {
+    for (int i = 0, length = array.length; i < length; i++) {
       if (toFind.equals(array[i])) {
         return i;
       }
@@ -451,7 +451,7 @@ public final class $Gson$Types {
       this.ownerType = ownerType == null ? null : canonicalize(ownerType);
       this.rawType = canonicalize(rawType);
       this.typeArguments = typeArguments.clone();
-      for (int t = 0; t < this.typeArguments.length; t++) {
+      for (int t = 0, length = this.typeArguments.length; t < length; t++) {
         checkNotNull(this.typeArguments[t]);
         checkNotPrimitive(this.typeArguments[t]);
         this.typeArguments[t] = canonicalize(this.typeArguments[t]);
@@ -482,15 +482,14 @@ public final class $Gson$Types {
     }
 
     @Override public String toString() {
-      StringBuilder stringBuilder = new StringBuilder(30 * (typeArguments.length + 1));
-      stringBuilder.append(typeToString(rawType));
-
-      if (typeArguments.length == 0) {
-        return stringBuilder.toString();
+      int length = typeArguments.length;
+      if (length == 0) {
+        return typeToString(rawType);
       }
 
-      stringBuilder.append("<").append(typeToString(typeArguments[0]));
-      for (int i = 1; i < typeArguments.length; i++) {
+      StringBuilder stringBuilder = new StringBuilder(30 * (length + 1));
+      stringBuilder.append(typeToString(rawType)).append("<").append(typeToString(typeArguments[0]));
+      for (int i = 1; i < length; i++) {
         stringBuilder.append(", ").append(typeToString(typeArguments[i]));
       }
       return stringBuilder.append(">").toString();

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

@@ -73,8 +73,10 @@ public final class ArrayTypeAdapter<E> extends TypeAdapter<Object> {
       list.add(instance);
     }
     in.endArray();
-    Object array = Array.newInstance(componentType, list.size());
-    for (int i = 0; i < list.size(); i++) {
+
+    int size = list.size();
+    Object array = Array.newInstance(componentType, size);
+    for (int i = 0; i < size; i++) {
       Array.set(array, i, list.get(i));
     }
     return array;

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

@@ -158,7 +158,7 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
         Type fieldType = $Gson$Types.resolve(type.getType(), raw, field.getGenericType());
         List<String> fieldNames = getFieldNames(field);
         BoundField previous = null;
-        for (int i = 0; i < fieldNames.size(); ++i) {
+        for (int i = 0, size = fieldNames.size(); i < size; ++i) {
           String name = fieldNames.get(i);
           if (i != 0) serialize = false; // only serialize the default name
           BoundField boundField = createBoundField(context, field, name,

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

@@ -69,33 +69,20 @@ public final class TypeAdapters {
   public static final TypeAdapter<Class> CLASS = new TypeAdapter<Class>() {
     @Override
     public void write(JsonWriter out, Class value) throws IOException {
-      if (value == null) {
-        out.nullValue();
-      } else {
-        throw new UnsupportedOperationException("Attempted to serialize java.lang.Class: "
-            + value.getName() + ". Forgot to register a type adapter?");
-      }
+      throw new UnsupportedOperationException("Attempted to serialize java.lang.Class: "
+              + value.getName() + ". Forgot to register a type adapter?");
     }
     @Override
     public Class read(JsonReader in) throws IOException {
-      if (in.peek() == JsonToken.NULL) {
-        in.nextNull();
-        return null;
-      } else {
-        throw new UnsupportedOperationException(
-            "Attempted to deserialize a java.lang.Class. Forgot to register a type adapter?");
-      }
+      throw new UnsupportedOperationException(
+              "Attempted to deserialize a java.lang.Class. Forgot to register a type adapter?");
     }
-  };
+  }.nullSafe();
+
   public static final TypeAdapterFactory CLASS_FACTORY = newFactory(Class.class, CLASS);
 
   public static final TypeAdapter<BitSet> BIT_SET = new TypeAdapter<BitSet>() {
     @Override public BitSet read(JsonReader in) throws IOException {
-      if (in.peek() == JsonToken.NULL) {
-        in.nextNull();
-        return null;
-      }
-
       BitSet bitset = new BitSet();
       in.beginArray();
       int i = 0;
@@ -132,19 +119,14 @@ public final class TypeAdapters {
     }
 
     @Override public void write(JsonWriter out, BitSet src) throws IOException {
-      if (src == null) {
-        out.nullValue();
-        return;
-      }
-
       out.beginArray();
-      for (int i = 0; i < src.length(); i++) {
+      for (int i = 0, length = src.length(); i < length; i++) {
         int value = (src.get(i)) ? 1 : 0;
         out.value(value);
       }
       out.endArray();
     }
-  };
+  }.nullSafe();
 
   public static final TypeAdapterFactory BIT_SET_FACTORY = newFactory(BitSet.class, BIT_SET);
 
@@ -922,4 +904,4 @@ public final class TypeAdapters {
       }
     };
   }
-}
+}