MethodHandles: Minor text nits.

Addresses some comments in review received after commit.

Test: m test-art-host-run-test-956-methodhandles
Bug: 30550796
Change-Id: I50c783f284f140155c0161c2e2da3e207c4f9943
diff --git a/dalvik/src/main/java/dalvik/system/EmulatedStackFrame.java b/dalvik/src/main/java/dalvik/system/EmulatedStackFrame.java
index f327c0c..0eea7c5 100644
--- a/dalvik/src/main/java/dalvik/system/EmulatedStackFrame.java
+++ b/dalvik/src/main/java/dalvik/system/EmulatedStackFrame.java
@@ -226,7 +226,7 @@
         }
 
         if (reference != null && !returnType.isInstance(reference)) {
-            throw new IllegalArgumentException("reference is not type " + returnType);
+            throw new IllegalArgumentException("reference is not of type " + returnType);
         }
 
         references[references.length - 1] = reference;
diff --git a/ojluni/src/main/java/java/lang/invoke/MethodHandles.java b/ojluni/src/main/java/java/lang/invoke/MethodHandles.java
index 482e6d2..5057d97 100644
--- a/ojluni/src/main/java/java/lang/invoke/MethodHandles.java
+++ b/ojluni/src/main/java/java/lang/invoke/MethodHandles.java
@@ -964,15 +964,19 @@
             MethodType constructorType =
                     MethodType.methodType(refc, constructor.getParameterTypes());
 
-            // String constructors have optimized StringFactoryForm that matches returned type.
+            // String constructors have optimized StringFactoryForm
+            // that matches returned type. These effectively combine the
+            // memory allocation and initialization calls into a single
+            // method.
             if (refc == String.class) {
                 // String <init> method is translated to a StringFactory method during execution.
                 return new MethodHandleImpl(constructor.getArtMethod(), MethodHandle.INVOKE_DIRECT,
                                             constructorType);
             }
 
-            // Other constructors use transform to perform allocation and then invoking
-            // the appropriate <init> method.
+            // Constructors for all other classes use a Construct transformer as there are no
+            // methods combining the allocation and calls to <init>. The Construct.tranform()
+            // performs the the memory allocation and then calls the <init> method.
             MethodType initType = initMethodType(constructorType);
             MethodHandle initHandle = new MethodHandleImpl(
                 constructor.getArtMethod(), MethodHandle.INVOKE_DIRECT, initType);
@@ -980,13 +984,20 @@
         }
 
         private static MethodType initMethodType(MethodType constructorType) {
-            // Constructor method types are (PT1,PT2,...)C.
-            // Class <init> method types are (C,PT1,PT2,...)V.
+            // Returns a MethodType appropriate for class <init>
+            // methods. Constructor MethodTypes have the form
+            // (PT1,PT2,...)C and class <init> MethodTypes have the
+            // form (C,PT1,PT2,...)V.
             assert constructorType.rtype() != void.class;
+
+            // Insert constructorType C as the first parameter type in
+            // the MethodType for <init>.
             Class<?> [] initPtypes = new Class<?> [constructorType.ptypes().length + 1];
             initPtypes[0] = constructorType.rtype();
             System.arraycopy(constructorType.ptypes(), 0, initPtypes, 1,
                              constructorType.ptypes().length);
+
+            // Set the return type for the <init> MethodType to be void.
             return MethodType.methodType(void.class, initPtypes);
         }