diff --git a/jre_emul/Classes/J2ObjC_common.m b/jre_emul/Classes/J2ObjC_common.m
index 567a6828b2..45a5bfce34 100644
--- a/jre_emul/Classes/J2ObjC_common.m
+++ b/jre_emul/Classes/J2ObjC_common.m
@@ -332,10 +332,10 @@ static void AppendArgs(
         JreStringBuilder_appendChar(sb, (jchar)va_arg(va, jint));
         break;
       case 'D':
-        RealToString_appendDouble(sb, va_arg(va, jdouble));
+        JreStringBuilder_appendDouble(sb, va_arg(va, jdouble));
         break;
       case 'F':
-        RealToString_appendFloat(sb, (jfloat)va_arg(va, jdouble));
+        JreStringBuilder_appendFloat(sb, (jfloat)va_arg(va, jdouble));
         break;
       case 'B':
       case 'I':
diff --git a/jre_emul/Classes/java/lang/AbstractStringBuilder.h b/jre_emul/Classes/java/lang/AbstractStringBuilder.h
index 27dcd96009..c6de566203 100644
--- a/jre_emul/Classes/java/lang/AbstractStringBuilder.h
+++ b/jre_emul/Classes/java/lang/AbstractStringBuilder.h
@@ -124,6 +124,8 @@ void JreStringBuilder_appendCharSequence(
     JreStringBuilder *sb, id<JavaLangCharSequence> s, jint start, jint end);
 void JreStringBuilder_appendInt(JreStringBuilder *sb, jint i);
 void JreStringBuilder_appendLong(JreStringBuilder *sb, jlong l);
+void JreStringBuilder_appendDouble(JreStringBuilder *sb, jdouble d);
+void JreStringBuilder_appendFloat(JreStringBuilder *sb, jfloat f);
 
 void JreStringBuilder_delete(JreStringBuilder *sb, jint start, jint end);
 void JreStringBuilder_deleteCharAt(JreStringBuilder *sb, jint index);
diff --git a/jre_emul/Classes/java/lang/AbstractStringBuilder.m b/jre_emul/Classes/java/lang/AbstractStringBuilder.m
index 1b536472a2..01b5be43ff 100644
--- a/jre_emul/Classes/java/lang/AbstractStringBuilder.m
+++ b/jre_emul/Classes/java/lang/AbstractStringBuilder.m
@@ -27,6 +27,7 @@
 #include "java_lang_Integer.h"
 #include "java_lang_Long.h"
 #include "libcore/util/EmptyArray.h"
+#include "sun/misc/FloatingDecimal.h"
 
 // Full name as expected by generated metadata.
 #define JavaLangAbstractStringBuilder_INITIAL_CAPACITY 16
@@ -235,6 +236,14 @@ void JreStringBuilder_appendLong(JreStringBuilder *sb, jlong l) {
   sb->count_ = newCount;
 }
 
+void JreStringBuilder_appendDouble(JreStringBuilder *sb, jdouble d) {
+  SunMiscFloatingDecimal_appendToWithDouble_withId_(d, (id)sb);
+}
+
+void JreStringBuilder_appendFloat(JreStringBuilder *sb, jfloat f) {
+  SunMiscFloatingDecimal_appendToWithFloat_withId_(f, (id)sb);
+}
+
 - (jint)capacity {
   return delegate_.bufferSize_;
 }
diff --git a/jre_emul/android/platform/libcore/ojluni/src/main/java/sun/misc/FloatingDecimal.java b/jre_emul/android/platform/libcore/ojluni/src/objc/java/sun/misc/FloatingDecimal.java
similarity index 98%
rename from jre_emul/android/platform/libcore/ojluni/src/main/java/sun/misc/FloatingDecimal.java
rename to jre_emul/android/platform/libcore/ojluni/src/objc/java/sun/misc/FloatingDecimal.java
index ddd8790bc1..2dfe219387 100644
--- a/jre_emul/android/platform/libcore/ojluni/src/main/java/sun/misc/FloatingDecimal.java
+++ b/jre_emul/android/platform/libcore/ojluni/src/objc/java/sun/misc/FloatingDecimal.java
@@ -28,6 +28,10 @@
 import java.util.Arrays;
 import java.util.regex.*;
 
+/*-[
+#include "java/lang/AbstractStringBuilder.h"
+]-*/
+
 /**
  * A class for converting between ASCII and decimal representations of a single
  * or double precision floating point number. Most conversions are provided via
@@ -81,20 +85,20 @@ public static String toJavaFormatString(float f) {
     }
 
     /**
-     * Appends a double precision floating point value to an <code>Appendable</code>.
+     * Appends a double precision floating point value to a <code>JreStringBuilder</code>.
      * @param d The double precision value.
-     * @param buf The <code>Appendable</code> with the value appended.
+     * @param buf The <code>JreStringBuilder</code> with the value appended.
      */
-    public static void appendTo(double d, Appendable buf) {
+    public static void appendTo(double d, Object buf) {
         getBinaryToASCIIConverter(d).appendTo(buf);
     }
 
     /**
-     * Appends a single precision floating point value to an <code>Appendable</code>.
+     * Appends a single precision floating point value to a <code>JreStringBuilder</code>.
      * @param f The single precision value.
-     * @param buf The <code>Appendable</code> with the value appended.
+     * @param buf The <code>JreStringBuilder</code> with the value appended.
      */
-    public static void appendTo(float f, Appendable buf) {
+    public static void appendTo(float f, Object buf) {
         getBinaryToASCIIConverter(f).appendTo(buf);
     }
 
@@ -134,10 +138,10 @@ public interface BinaryToASCIIConverter {
         public String toJavaFormatString();
 
         /**
-         * Appends a floating point value to an <code>Appendable</code>.
-         * @param buf The <code>Appendable</code> to receive the value.
+         * Appends a floating point value to a <code>JreStringBuilder</code>.
+         * @param buf The <code>JreStringBuilder</code> to receive the value.
          */
-        public void appendTo(Appendable buf);
+        public void appendTo(Object buf);
 
         /**
          * Retrieves the decimal exponent most closely corresponding to this value.
@@ -201,15 +205,9 @@ public String toJavaFormatString() {
         }
 
         @Override
-        public void appendTo(Appendable buf) {
-            if (buf instanceof StringBuilder) {
-                ((StringBuilder) buf).append(image);
-            } else if (buf instanceof StringBuffer) {
-                ((StringBuffer) buf).append(image);
-            } else {
-                assert false;
-            }
-        }
+        public native void appendTo(Object buf) /*-[
+          JreStringBuilder_appendString((JreStringBuilder *)buf, image_);
+        ]-*/;
 
         @Override
         public int getDecimalExponent() {
@@ -303,16 +301,11 @@ public String toJavaFormatString() {
         }
 
         @Override
-        public void appendTo(Appendable buf) {
-            int len = getChars(buffer);
-            if (buf instanceof StringBuilder) {
-                ((StringBuilder) buf).append(buffer, 0, len);
-            } else if (buf instanceof StringBuffer) {
-                ((StringBuffer) buf).append(buffer, 0, len);
-            } else {
-                assert false;
-            }
-        }
+        public native void appendTo(Object buf) /*-[
+          jint len = SunMiscFloatingDecimal_BinaryToASCIIBuffer_getCharsWithCharArray_(
+              self, buffer_);
+          JreStringBuilder_appendCharArraySubset((JreStringBuilder *)buf, buffer_, 0, len);
+        ]-*/;
 
         @Override
         public int getDecimalExponent() {