diff --git a/gson/src/main/java/com/google/gson/Gson.java b/gson/src/main/java/com/google/gson/Gson.java
index 186425c6..7724bf94 100644
--- a/gson/src/main/java/com/google/gson/Gson.java
+++ b/gson/src/main/java/com/google/gson/Gson.java
@@ -17,8 +17,9 @@
 package com.google.gson;
 
 import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonToken;
 import com.google.gson.stream.JsonWriter;
-
+import com.google.gson.stream.MalformedJsonException;
 import java.io.IOException;
 import java.io.Reader;
 import java.io.StringReader;
@@ -455,6 +456,7 @@ public final class Gson {
   public <T> T fromJson(Reader json, Class<T> classOfT) throws JsonSyntaxException, JsonIOException {
     JsonReader jsonReader = new JsonReader(json);
     Object object = fromJson(jsonReader, classOfT);
+    assertFullConsumption(object, jsonReader);
     return Primitives.wrap(classOfT).cast(object);
   }
 
@@ -479,7 +481,21 @@ public final class Gson {
    */
   public <T> T fromJson(Reader json, Type typeOfT) throws JsonIOException, JsonSyntaxException {
     JsonReader jsonReader = new JsonReader(json);
-    return this.<T>fromJson(jsonReader, typeOfT);
+    T object = this.<T>fromJson(jsonReader, typeOfT);
+    assertFullConsumption(object, jsonReader);
+    return object;
+  }
+
+  private static void assertFullConsumption(Object obj, JsonReader reader) {
+    try {
+      if (obj != null && reader.peek() != JsonToken.END_DOCUMENT) {
+        throw new JsonIOException("JSON document was not fully consumed.");
+      }
+    } catch (MalformedJsonException e) {
+      throw new JsonSyntaxException(e);
+    } catch (IOException e) {
+      throw new JsonIOException(e);
+    }
   }
 
   /**
diff --git a/gson/src/main/java/com/google/gson/JsonParser.java b/gson/src/main/java/com/google/gson/JsonParser.java
index 584ef7f0..a2eef8ad 100755
--- a/gson/src/main/java/com/google/gson/JsonParser.java
+++ b/gson/src/main/java/com/google/gson/JsonParser.java
@@ -16,8 +16,10 @@
 package com.google.gson;
 
 import com.google.gson.stream.JsonReader;
-
+import com.google.gson.stream.JsonToken;
+import com.google.gson.stream.MalformedJsonException;
 import java.io.EOFException;
+import java.io.IOException;
 import java.io.Reader;
 import java.io.StringReader;
 
@@ -51,8 +53,20 @@ public final class JsonParser {
    * @since 1.3
    */
   public JsonElement parse(Reader json) throws JsonIOException, JsonSyntaxException {
-    JsonReader jsonReader = new JsonReader(json);
-    return parse(jsonReader);
+    try {
+      JsonReader jsonReader = new JsonReader(json);
+      JsonElement element = parse(jsonReader);
+      if (!element.isJsonNull() && jsonReader.peek() != JsonToken.END_DOCUMENT) {
+        throw new JsonSyntaxException("Did not consume the entire document.");
+      }
+      return element;
+    } catch (MalformedJsonException e) {
+      throw new JsonSyntaxException(e);
+    } catch (IOException e) {
+      throw new JsonIOException(e);
+    } catch (NumberFormatException e) {
+      throw new JsonSyntaxException(e);
+    }
   }
 
   /**