diff --git a/zipkin-finatra/src/main/scala/com/twitter/zipkin/adapter/JsonAdapter.scala b/zipkin-finatra/src/main/scala/com/twitter/zipkin/adapter/JsonAdapter.scala
index 8263f55876..79e568e2fb 100644
--- a/zipkin-finatra/src/main/scala/com/twitter/zipkin/adapter/JsonAdapter.scala
+++ b/zipkin-finatra/src/main/scala/com/twitter/zipkin/adapter/JsonAdapter.scala
@@ -24,7 +24,7 @@ object JsonAdapter extends Adapter {
 
   def apply(b: BinaryAnnotation): binaryAnnotationType = {
     val value = b.annotationType match {
-      case AnnotationType(0, _) => if (b.value.get() == 0) false else true  // bool
+      case AnnotationType(0, _) => if (b.value.get() != 0) true else false  // bool
       case AnnotationType(1, _) => new String(b.value.array(), b.value.position(), b.value.remaining()) // bytes
       case AnnotationType(2, _) => b.value.getShort            // i16
       case AnnotationType(3, _) => b.value.getInt              // i32
diff --git a/zipkin-finatra/src/test/scala/com/twitter/zipkin/adapter/JsonAdapterSpec.scala b/zipkin-finatra/src/test/scala/com/twitter/zipkin/adapter/JsonAdapterSpec.scala
new file mode 100644
index 0000000000..d4063db4f0
--- /dev/null
+++ b/zipkin-finatra/src/test/scala/com/twitter/zipkin/adapter/JsonAdapterSpec.scala
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2012 Twitter 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.twitter.zipkin.adapter
+
+import com.twitter.zipkin.common.{AnnotationType, BinaryAnnotation}
+import java.nio.ByteBuffer
+import org.specs.Specification
+import org.specs.mock.{ClassMocker, JMocker}
+
+class JsonAdapterSpec extends Specification with JMocker with ClassMocker {
+  "JsonAdapter" should {
+    "convert binary annotations" in {
+      val key = "key"
+
+      "bool" in {
+        val trueAnnotation = BinaryAnnotation(key, ByteBuffer.wrap(Array[Byte](1)), AnnotationType.Bool, None)
+        val falseAnnotation = BinaryAnnotation(key, ByteBuffer.wrap(Array[Byte](0)), AnnotationType.Bool, None)
+
+        val trueConvert = JsonAdapter(trueAnnotation)
+        trueConvert.value must_== true
+
+        val falseConvert = JsonAdapter(falseAnnotation)
+        falseConvert.value must_== false
+      }
+
+      "short" in {
+        val ann = BinaryAnnotation(key, ByteBuffer.allocate(2).putShort(0, 5.toShort), AnnotationType.I16, None)
+        val convert = JsonAdapter(ann)
+        convert.value must_== 5
+      }
+
+      "int" in {
+        val ann = BinaryAnnotation(key, ByteBuffer.allocate(4).putInt(0, 6), AnnotationType.I32, None)
+        val convert = JsonAdapter(ann)
+        convert.value must_== 6
+      }
+
+      "long" in {
+        val ann = BinaryAnnotation(key, ByteBuffer.allocate(8).putLong(0, 99999999999L), AnnotationType.I64, None)
+        val convert = JsonAdapter(ann)
+        convert.value must_== 99999999999L
+      }
+
+      "double" in {
+        val ann = BinaryAnnotation(key, ByteBuffer.allocate(8).putDouble(0, 1.3496), AnnotationType.Double, None)
+        val convert = JsonAdapter(ann)
+        convert.value must_== 1.3496
+      }
+
+      "string" in {
+        val ann = BinaryAnnotation(key, ByteBuffer.wrap("HELLO!".getBytes), AnnotationType.String, None)
+        val convert = JsonAdapter(ann)
+        convert.value must_== "HELLO!"
+      }
+    }
+  }
+}