Remove unnecessary generic type arguments

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=175155365

java/google/registry/request/Modules.java

@@ -245,7 +245,7 @@ public final class Modules {
           // GoogleCredential constructor.  We don't yet know the actual scopes to use here, and it
           // is thus the responsibility of every user of a delegated admin credential to call
           // createScoped() on it first to get the version with the correct scopes set.
-          .setServiceAccountScopes(ImmutableSet.<String>of())
+          .setServiceAccountScopes(ImmutableSet.of())
           .setServiceAccountUser(gSuiteAdminAccountEmailAddress)
           .build();
     }

java/google/registry/request/RequestParameters.java

@@ -70,7 +70,7 @@ public final class RequestParameters {
     String stringParam = req.getParameter(name);
     try {
       return isNullOrEmpty(stringParam)
-          ? Optional.<Integer>empty()
+          ? Optional.empty()
           : Optional.of(Integer.valueOf(stringParam));
     } catch (NumberFormatException e) {
       throw new BadRequestException("Expected integer: " + name);
@@ -93,7 +93,7 @@ public final class RequestParameters {
   /** Returns all GET or POST parameters associated with {@code name}. */
   public static ImmutableSet<String> extractSetOfParameters(HttpServletRequest req, String name) {
     String[] parameters = req.getParameterValues(name);
-    return parameters == null ? ImmutableSet.<String>of() : ImmutableSet.copyOf(parameters);
+    return parameters == null ? ImmutableSet.of() : ImmutableSet.copyOf(parameters);
   }
 
   /**
@@ -135,7 +135,7 @@ public final class RequestParameters {
       HttpServletRequest req, String name) {
     String stringParam = req.getParameter(name);
     return isNullOrEmpty(stringParam)
-        ? Optional.<Boolean>empty()
+        ? Optional.empty()
         : Optional.of(Boolean.valueOf(stringParam));
   }
 
@@ -179,7 +179,7 @@ public final class RequestParameters {
     String stringParam = req.getParameter(name);
     try {
       return isNullOrEmpty(stringParam)
-          ? Optional.<DateTime>empty()
+          ? Optional.empty()
           : Optional.of(DateTime.parse(stringParam));
     } catch (IllegalArgumentException e) {
       throw new BadRequestException("Bad ISO 8601 timestamp: " + name);
@@ -198,7 +198,7 @@ public final class RequestParameters {
       HttpServletRequest req, String name) {
     String[] stringParams = req.getParameterValues(name);
     if (stringParams == null) {
-      return ImmutableSet.<DateTime>of();
+      return ImmutableSet.of();
     }
     ImmutableSet.Builder<DateTime> datesBuilder = new ImmutableSet.Builder<>();
     for (String stringParam : stringParams) {

java/google/registry/request/auth/AuthModule.java

@@ -30,7 +30,7 @@ public class AuthModule {
   @Provides
   ImmutableList<AuthenticationMechanism> provideApiAuthenticationMechanisms(
       OAuthAuthenticationMechanism oauthAuthenticationMechanism) {
-    return ImmutableList.<AuthenticationMechanism>of(
+    return ImmutableList.of(
         oauthAuthenticationMechanism);
   }
 

java/google/registry/request/auth/AuthResult.java

@@ -37,7 +37,7 @@ public abstract class AuthResult {
   }
 
   public static AuthResult create(AuthLevel authLevel) {
-    return new AutoValue_AuthResult(authLevel, Optional.<UserAuthInfo>empty());
+    return new AutoValue_AuthResult(authLevel, Optional.empty());
   }
 
   public static AuthResult create(AuthLevel authLevel, @Nullable UserAuthInfo userAuthInfo) {

java/google/registry/request/auth/UserAuthInfo.java

@@ -39,7 +39,7 @@ public abstract class UserAuthInfo {
 
   public static UserAuthInfo create(
       User user, boolean isUserAdmin) {
-    return new AutoValue_UserAuthInfo(user, isUserAdmin, Optional.<OAuthTokenInfo>empty());
+    return new AutoValue_UserAuthInfo(user, isUserAdmin, Optional.empty());
   }
 
   public static UserAuthInfo create(