diff --git a/build.gradle b/build.gradle
index ef00fa9dacb..5152eedbcfa 100644
--- a/build.gradle
+++ b/build.gradle
@@ -21,9 +21,9 @@ plugins {
     id "signing"
     id "checkstyle"
     id "jacoco"
-    id "com.github.spotbugs" version "1.6.10"
+    id "com.github.spotbugs" version "4.6.0"
     id "io.codearte.nexus-staging" version "0.21.0"
-    id "me.champeau.gradle.jmh" version "0.4.6"
+    id "me.champeau.gradle.jmh" version "0.5.2"
 }
 
 ext {
@@ -52,10 +52,10 @@ subprojects {
     }
 
     dependencies {
-        testCompile "org.junit.jupiter:junit-jupiter-api:5.4.0"
-        testRuntime "org.junit.jupiter:junit-jupiter-engine:5.4.0"
-        testCompile "org.junit.jupiter:junit-jupiter-params:5.4.0"
-        testCompile "org.hamcrest:hamcrest:2.1"
+        testImplementation "org.junit.jupiter:junit-jupiter-api:5.4.0"
+        testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:5.4.0"
+        testImplementation "org.junit.jupiter:junit-jupiter-params:5.4.0"
+        testImplementation "org.hamcrest:hamcrest:2.1"
     }
 
     // Reusable license copySpec for building JARs
@@ -210,7 +210,7 @@ subprojects {
     // Configure the bug filter for spotbugs.
     spotbugs {
         effort = "max"
-        excludeFilterConfig = project.resources.text.fromFile("${project.rootDir}/config/spotbugs/filter.xml")
+        excludeFilter = file("${project.rootDir}/config/spotbugs/filter.xml")
     }
 }
 
diff --git a/config/checkstyle/checkstyle.xml b/config/checkstyle/checkstyle.xml
index 27e828de963..527d2a4c89c 100644
--- a/config/checkstyle/checkstyle.xml
+++ b/config/checkstyle/checkstyle.xml
@@ -15,11 +15,11 @@
   -->
 
 <!DOCTYPE module PUBLIC
-        "-//Puppy Crawl//DTD Check Configuration 1.2//EN"
-        "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">
+  "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
+  "https://checkstyle.org/dtds/configuration_1_3.dtd">
 
 <module name="Checker">
-    <module name="SuppressWarningsFilter" />
+    <module name="SuppressWarningsFilter"/>
 
     <module name="SuppressionFilter">
         <property name="file" value="${config_loc}/suppressions.xml"/>
@@ -40,6 +40,12 @@
         <property name="lineSeparator" value="lf_cr_crlf"/>
     </module>
 
+    <!-- See http://checkstyle.sf.net/config_sizes.html -->
+    <module name="LineLength">
+        <property name="max" value="${checkstyle.linelength}" default="120"/>
+        <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
+    </module>
+
     <!-- Checks for whitespace                               -->
     <!-- See http://checkstyle.sf.net/config_whitespace.html -->
     <module name="FileTabCharacter"/>
@@ -53,13 +59,6 @@
         <module name="SuppressWarningsHolder"/>
         <module name="SuppressionCommentFilter"/>
 
-        <!-- Checks for Size Violations.                    -->
-        <!-- See http://checkstyle.sf.net/config_sizes.html -->
-        <module name="LineLength">
-            <property name="max" value="${checkstyle.linelength}" default="120"/>
-            <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
-        </module>
-
         <!-- Checks for imports                              -->
         <!-- See http://checkstyle.sf.net/config_import.html -->
         <module name="NoLineWrap"/>
@@ -81,12 +80,8 @@
         <module name="JavadocMethod">
             <property name="scope" value="public"/>
             <property name="allowMissingParamTags" value="true"/>
-            <property name="allowMissingThrowsTags" value="true"/>
             <property name="allowMissingReturnTag" value="true"/>
-            <property name="minLineCount" value="2"/>
             <property name="allowedAnnotations" value="Override, Test"/>
-            <property name="allowThrowsTagsForSubclasses" value="true"/>
-            <property name="allowMissingJavadoc" value="true"/>
         </module>
         <module name="JavadocStyle"/>
         <module name="NonEmptyAtclauseDescription"/>
@@ -157,7 +152,9 @@
             <property name="tokens" value="LITERAL_TRY, LITERAL_FINALLY, LITERAL_IF, LITERAL_ELSE, LITERAL_SWITCH"/>
         </module>
         <module name="LeftCurly"/>
-        <module name="NeedBraces"/>
+        <module name="NeedBraces">
+            <property name="allowEmptyLoopBody" value="true"/>
+        </module>
         <module name="RightCurly">
             <property name="id" value="RightCurlySame"/>
             <property name="tokens"
@@ -167,12 +164,11 @@
             <property name="id" value="RightCurlyAlone"/>
             <property name="option" value="alone"/>
             <property name="tokens"
-                      value="CLASS_DEF, METHOD_DEF, CTOR_DEF, LITERAL_FOR, LITERAL_WHILE, STATIC_INIT, INSTANCE_INIT"/>
+                      value="CLASS_DEF, METHOD_DEF, LITERAL_FOR, LITERAL_WHILE, STATIC_INIT, INSTANCE_INIT"/>
         </module>
 
         <!-- Checks for common coding problems               -->
         <!-- See http://checkstyle.sf.net/config_coding.html -->
-        <module name="EmptyStatement"/>
         <module name="EqualsHashCode"/>
         <module name="IllegalInstantiation"/>
         <module name="InnerAssignment"/>
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 87b738cbd05..e708b1c023e 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index f4d7b2bf616..da9702f9e70 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.4.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
index af6708ff229..4f906e0c811 100755
--- a/gradlew
+++ b/gradlew
@@ -1,5 +1,21 @@
 #!/usr/bin/env sh
 
+#
+# Copyright 2015 the original author or authors.
+#
+# 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
+#
+#      https://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.
+#
+
 ##############################################################################
 ##
 ##  Gradle start up script for UN*X
@@ -28,7 +44,7 @@ APP_NAME="Gradle"
 APP_BASE_NAME=`basename "$0"`
 
 # Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='"-Xmx64m"'
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD="maximum"
@@ -66,6 +82,7 @@ esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
+
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
     if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
@@ -109,10 +126,11 @@ if $darwin; then
     GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
 fi
 
-# For Cygwin, switch paths to Windows format before running java
-if $cygwin ; then
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
     APP_HOME=`cygpath --path --mixed "$APP_HOME"`
     CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+
     JAVACMD=`cygpath --unix "$JAVACMD"`
 
     # We build the pattern for arguments to be converted via cygpath
@@ -138,19 +156,19 @@ if $cygwin ; then
         else
             eval `echo args$i`="\"$arg\""
         fi
-        i=$((i+1))
+        i=`expr $i + 1`
     done
     case $i in
-        (0) set -- ;;
-        (1) set -- "$args0" ;;
-        (2) set -- "$args0" "$args1" ;;
-        (3) set -- "$args0" "$args1" "$args2" ;;
-        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
     esac
 fi
 
@@ -159,14 +177,9 @@ save () {
     for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
     echo " "
 }
-APP_ARGS=$(save "$@")
+APP_ARGS=`save "$@"`
 
 # Collect all arguments for the java command, following the shell quoting and substitution rules
 eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
 
-# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
-if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
-  cd "$(dirname "$0")"
-fi
-
 exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
index 0f8d5937c4a..ac1b06f9382 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -1,3 +1,19 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
 @if "%DEBUG%" == "" @echo off
 @rem ##########################################################################
 @rem
@@ -13,15 +29,18 @@ if "%DIRNAME%" == "" set DIRNAME=.
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS="-Xmx64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto init
+if "%ERRORLEVEL%" == "0" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
@@ -35,7 +54,7 @@ goto fail
 set JAVA_HOME=%JAVA_HOME:"=%
 set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
-if exist "%JAVA_EXE%" goto init
+if exist "%JAVA_EXE%" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
@@ -45,28 +64,14 @@ echo location of your Java installation.
 
 goto fail
 
-:init
-@rem Get command-line arguments, handling Windows variants
-
-if not "%OS%" == "Windows_NT" goto win9xME_args
-
-:win9xME_args
-@rem Slurp the command line arguments.
-set CMD_LINE_ARGS=
-set _SKIP=2
-
-:win9xME_args_slurp
-if "x%~1" == "x" goto execute
-
-set CMD_LINE_ARGS=%*
-
 :execute
 @rem Setup the command line
 
 set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
+
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
 
 :end
 @rem End local scope for the variables with windows NT shell
diff --git a/smithy-aws-cloudformation/build.gradle b/smithy-aws-cloudformation/build.gradle
index 299ae87a0db..19bfb96fe64 100644
--- a/smithy-aws-cloudformation/build.gradle
+++ b/smithy-aws-cloudformation/build.gradle
@@ -33,5 +33,5 @@ dependencies {
 
     // For use in validating schemas used in tests against the supplied
     // CloudFormation definition schema.
-    testCompile("com.github.everit-org.json-schema:org.everit.json.schema:1.12.1")
+    testImplementation("com.github.everit-org.json-schema:org.everit.json.schema:1.12.1")
 }
diff --git a/smithy-aws-cloudformation/src/main/java/software/amazon/smithy/aws/cloudformation/schema/fromsmithy/CfnMapper.java b/smithy-aws-cloudformation/src/main/java/software/amazon/smithy/aws/cloudformation/schema/fromsmithy/CfnMapper.java
index c874f17e460..9fab715f5fd 100644
--- a/smithy-aws-cloudformation/src/main/java/software/amazon/smithy/aws/cloudformation/schema/fromsmithy/CfnMapper.java
+++ b/smithy-aws-cloudformation/src/main/java/software/amazon/smithy/aws/cloudformation/schema/fromsmithy/CfnMapper.java
@@ -48,7 +48,8 @@ default byte getOrder() {
      * @param context Conversion context.
      * @param builder ResourceSchema builder to modify.
      */
-    default void before(Context context, ResourceSchema.Builder builder) {}
+    default void before(Context context, ResourceSchema.Builder builder) {
+    }
 
     /**
      * Updates an ResourceSchema.Builder after converting the model.
diff --git a/smithy-aws-protocol-tests/build.gradle b/smithy-aws-protocol-tests/build.gradle
index cc7649bb732..6fcaa8dc0a6 100644
--- a/smithy-aws-protocol-tests/build.gradle
+++ b/smithy-aws-protocol-tests/build.gradle
@@ -25,7 +25,7 @@ ext {
 }
 
 dependencies {
-    compile project(":smithy-cli")
+    implementation project(":smithy-cli")
     implementation project(":smithy-protocol-test-traits")
     implementation project(":smithy-aws-traits")
 }
diff --git a/smithy-cli/build.gradle b/smithy-cli/build.gradle
index bb0b737d87b..6bb25dd05f3 100644
--- a/smithy-cli/build.gradle
+++ b/smithy-cli/build.gradle
@@ -33,7 +33,7 @@ dependencies {
 }
 
 application {
-    mainClassName = "software.amazon.smithy.cli.SmithyCli"
+    mainClass = "software.amazon.smithy.cli.SmithyCli"
     applicationName = "smithy"
     applicationDefaultJvmArgs = ["-XX:TieredStopAtLevel=2", "-Xshare:auto"]
 }
diff --git a/smithy-cli/src/main/java/software/amazon/smithy/cli/Cli.java b/smithy-cli/src/main/java/software/amazon/smithy/cli/Cli.java
index 1c56e81ca72..ee66abc4611 100644
--- a/smithy-cli/src/main/java/software/amazon/smithy/cli/Cli.java
+++ b/smithy-cli/src/main/java/software/amazon/smithy/cli/Cli.java
@@ -405,9 +405,11 @@ public void publish(LogRecord record) {
         }
 
         @Override
-        public void flush() {}
+        public void flush() {
+        }
 
         @Override
-        public void close() {}
+        public void close() {
+        }
     }
 }
diff --git a/smithy-model/src/main/java/software/amazon/smithy/model/loader/AstModelLoader.java b/smithy-model/src/main/java/software/amazon/smithy/model/loader/AstModelLoader.java
index aa16f5d8b46..6249289e98b 100644
--- a/smithy-model/src/main/java/software/amazon/smithy/model/loader/AstModelLoader.java
+++ b/smithy-model/src/main/java/software/amazon/smithy/model/loader/AstModelLoader.java
@@ -21,7 +21,6 @@
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
-
 import software.amazon.smithy.model.SourceException;
 import software.amazon.smithy.model.node.Node;
 import software.amazon.smithy.model.node.ObjectNode;
diff --git a/smithy-openapi/src/main/java/software/amazon/smithy/openapi/fromsmithy/OpenApiMapper.java b/smithy-openapi/src/main/java/software/amazon/smithy/openapi/fromsmithy/OpenApiMapper.java
index 1f28bf7e1a5..fbb9e17e037 100644
--- a/smithy-openapi/src/main/java/software/amazon/smithy/openapi/fromsmithy/OpenApiMapper.java
+++ b/smithy-openapi/src/main/java/software/amazon/smithy/openapi/fromsmithy/OpenApiMapper.java
@@ -68,7 +68,8 @@ default byte getOrder() {
      * @param model Model being converted.
      * @param config Configuration object to modify.
      */
-    default void updateDefaultSettings(Model model, OpenApiConfig config) {}
+    default void updateDefaultSettings(Model model, OpenApiConfig config) {
+    }
 
     /**
      * Updates an operation before invoking the plugin system on the contents
@@ -196,7 +197,8 @@ default ResponseObject updateResponse(
      * @param context Conversion context.
      * @param builder OpenAPI builder to modify.
      */
-    default void before(Context<? extends Trait> context, OpenApi.Builder builder) {}
+    default void before(Context<? extends Trait> context, OpenApi.Builder builder) {
+    }
 
     /**
      * Updates a security scheme object.
diff --git a/smithy-utils/src/main/java/software/amazon/smithy/utils/CodeFormatter.java b/smithy-utils/src/main/java/software/amazon/smithy/utils/CodeFormatter.java
index e032db1cb6c..5237bd8a09b 100644
--- a/smithy-utils/src/main/java/software/amazon/smithy/utils/CodeFormatter.java
+++ b/smithy-utils/src/main/java/software/amazon/smithy/utils/CodeFormatter.java
@@ -142,7 +142,7 @@ private void parsePositionalArgument(State state, boolean insideBrace) {
         expectConsistentRelativePositionals(state, state.relativeIndex <= 0);
         state.relativeIndex = -1;
         int startPosition = state.position;
-        while (state.next() && Character.isDigit(state.c())) {}
+        while (state.next() && Character.isDigit(state.c()));
         int index = Integer.parseInt(state.expression.substring(startPosition, state.position)) - 1;
 
         if (index < 0 || index >= state.args.length) {