diff --git a/approvaltests-tests/src/test/java/org/approvaltests/DocumentHelpersTest.listAllVerifyFunctions.approved.md b/approvaltests-tests/src/test/java/org/approvaltests/DocumentHelpersTest.listAllVerifyFunctions.approved.md
index 450fb044..a596a68a 100644
--- a/approvaltests-tests/src/test/java/org/approvaltests/DocumentHelpersTest.listAllVerifyFunctions.approved.md
+++ b/approvaltests-tests/src/test/java/org/approvaltests/DocumentHelpersTest.listAllVerifyFunctions.approved.md
@@ -72,10 +72,10 @@
  * CombinationApprovals. [verifyBestCoveringPairs ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/combinations/CombinationApprovals.java#L653-L661) (Labels, Function8, Object[], Object[], Object[], Object[], Object[], Object[], Object[], Object[], $\color{#AAA}{\textsf{Options}}$)  
  * CombinationApprovals. [verifyBestCoveringPairs ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/combinations/CombinationApprovals.java#L690-L697) (Labels, Function9, Object[], Object[], Object[], Object[], Object[], Object[], Object[], Object[], Object[], $\color{#AAA}{\textsf{Options}}$)  
  * JsonApprovals. [verifyAsJson ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/JsonApprovals.java#L63-L66) (Object, $\color{#AAA}{\textsf{Options}}$)  
- * JsonApprovals. [verifyAsJson ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/JsonApprovals.java#L57-L60) (Object, Function1, $\color{#AAA}{\textsf{Options}}$)  
- * JsonApprovals. [verifyJson ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/JsonApprovals.java#L18-L21) (String, $\color{#AAA}{\textsf{Options}}$)  
- * JsonApprovals. [verifyJson ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/JsonApprovals.java#L42-L45) (String, boolean, $\color{#AAA}{\textsf{Options}}$)  
- * JsonApprovals. [verifyJson ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/JsonApprovals.java#L33-L40) (String, boolean, Function1, $\color{#AAA}{\textsf{Options}}$)  
+ * JsonApprovals. [verifyAsJson ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/JsonApprovals.java#L56-L60) (Object, Function1, $\color{#AAA}{\textsf{Options}}$)  
+ * JsonApprovals. [verifyJson ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/JsonApprovals.java#L17-L20) (String, $\color{#AAA}{\textsf{Options}}$)  
+ * JsonApprovals. [verifyJson ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/JsonApprovals.java#L41-L44) (String, boolean, $\color{#AAA}{\textsf{Options}}$)  
+ * JsonApprovals. [verifyJson ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/JsonApprovals.java#L32-L39) (String, boolean, Function1, $\color{#AAA}{\textsf{Options}}$)  
  * JsonJackson3Approvals. [verifyAsJson ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/JsonJackson3Approvals.java#L24-L27) (Object, $\color{#AAA}{\textsf{Options}}$)  
  * JsonJackson3Approvals. [verifyAsJson ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/JsonJackson3Approvals.java#L34-L38) (Object, Function1, $\color{#AAA}{\textsf{Options}}$)  
  * JsonJacksonApprovals. [verifyAsJson ](https://github.com/approvals/ApprovalTests.Java/blob/master/approvaltests/src/main/java/org/approvaltests/JsonJacksonApprovals.java#L18-L21) (Object, $\color{#AAA}{\textsf{Options}}$)  
diff --git a/approvaltests-tests/src/test/java/org/approvaltests/JsonApprovalsTest.java b/approvaltests-tests/src/test/java/org/approvaltests/JsonApprovalsTest.java
index ea15542b..df80ff5c 100644
--- a/approvaltests-tests/src/test/java/org/approvaltests/JsonApprovalsTest.java
+++ b/approvaltests-tests/src/test/java/org/approvaltests/JsonApprovalsTest.java
@@ -12,7 +12,7 @@ public class JsonApprovalsTest
   void nullDateTest()
   {
     LocalDateWrapper localDateWrapper = new LocalDateWrapper();
-    JsonApprovals.verifyAsJson(localDateWrapper, g -> g.serializeNulls());
+    JsonApprovals.verifyAsJson(localDateWrapper, (GsonBuilder g) -> g.serializeNulls());
   }
 
   @Test
@@ -43,7 +43,7 @@ public void setLocalDate(LocalDateTime localDate)
   void nullInstantTest()
   {
     InstantWrapper instantWrapper = new InstantWrapper();
-    JsonApprovals.verifyAsJson(instantWrapper, g -> g.serializeNulls());
+    JsonApprovals.verifyAsJson(instantWrapper, (GsonBuilder g) -> g.serializeNulls());
   }
   private class InstantWrapper
   {
diff --git a/approvaltests-tests/src/test/java/org/approvaltests/JsonFormattingTest.java b/approvaltests-tests/src/test/java/org/approvaltests/JsonFormattingTest.java
index 99122e94..65683eac 100644
--- a/approvaltests-tests/src/test/java/org/approvaltests/JsonFormattingTest.java
+++ b/approvaltests-tests/src/test/java/org/approvaltests/JsonFormattingTest.java
@@ -78,6 +78,6 @@ public void testJsonFieldOrderingWithNulls()
   {
     Approvals.settings().allowMultipleVerifyCallsForThisMethod();
     String json1 = "{\"infos\":{\"address\":null,\"phone\":\"my phone\"},\"insurance\":{\"forks\":[14,53,123],\"prices\":[5,8,\"3%\"]}}";
-    JsonApprovals.verifyJson(json1, true, g -> g.serializeNulls());
+    JsonApprovals.verifyJson(json1, true, (GsonBuilder g) -> g.serializeNulls());
   }
 }
diff --git a/approvaltests/src/main/java/org/approvaltests/JsonApprovals.java b/approvaltests/src/main/java/org/approvaltests/JsonApprovals.java
index 55c972de..36d21940 100644
--- a/approvaltests/src/main/java/org/approvaltests/JsonApprovals.java
+++ b/approvaltests/src/main/java/org/approvaltests/JsonApprovals.java
@@ -1,6 +1,5 @@
 package org.approvaltests;
 
-import com.google.gson.GsonBuilder;
 import com.spun.util.JsonUtils;
 import org.approvaltests.core.Options;
 import org.lambda.functions.Function1;
@@ -25,17 +24,17 @@ public static void verifyJson(String json, boolean reorderJson)
     verifyJson(json, reorderJson, new Options());
   }
 
-  public static void verifyJson(String json, boolean reorderJson, Function1<GsonBuilder, GsonBuilder> gsonBuilder)
+  public static <T> void verifyJson(String json, boolean reorderJson, Function1<T, T> gsonBuilder)
   {
     verifyJson(json, reorderJson, gsonBuilder, new Options());
   }
 
-  public static void verifyJson(String json, boolean reorderJson, Function1<GsonBuilder, GsonBuilder> gsonBuilder,
-      Options options)
+  @SuppressWarnings("unchecked")
+  public static <T> void verifyJson(String json, boolean reorderJson, Function1<T, T> gsonBuilder, Options options)
   {
     String formattedJson = reorderJson
-        ? JsonUtils.reorderFields(json, gsonBuilder)
-        : JsonUtils.prettyPrint(json, gsonBuilder);
+        ? JsonUtils.reorderFields(json, (Function1) gsonBuilder)
+        : JsonUtils.prettyPrint(json, (Function1) gsonBuilder);
     Approvals.verify(formattedJson, options.forFile().withExtension(".json"));
   }
 
@@ -49,14 +48,15 @@ public static void verifyAsJson(Object o)
     verifyAsJson(o, new Options());
   }
 
-  public static void verifyAsJson(Object o, Function1<GsonBuilder, GsonBuilder> gsonBuilder)
+  public static <T> void verifyAsJson(Object o, Function1<T, T> gsonBuilder)
   {
     verifyAsJson(o, gsonBuilder, new Options());
   }
 
-  public static void verifyAsJson(Object o, Function1<GsonBuilder, GsonBuilder> gsonBuilder, Options options)
+  @SuppressWarnings("unchecked")
+  public static <T> void verifyAsJson(Object o, Function1<T, T> gsonBuilder, Options options)
   {
-    Approvals.verify(JsonUtils.asJson(o, gsonBuilder), options.forFile().withExtension(".json"));
+    Approvals.verify(JsonUtils.asJson(o, (Function1) gsonBuilder), options.forFile().withExtension(".json"));
   }
 
   // begin-snippet: verify_as_json