diff --git a/.github/workflows/build-and-test.yml b/.github/workflows/build-and-test.yml
index e0266407..bf6d9c76 100644
--- a/.github/workflows/build-and-test.yml
+++ b/.github/workflows/build-and-test.yml
@@ -9,7 +9,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-java@v4
         with:
-          java-version: '17'
+          java-version: '21'
           distribution: 'temurin'
 
       - name: Setup Gradle
@@ -33,7 +33,7 @@ jobs:
   test-suite:
     strategy:
       matrix:
-        java: ['17', '11', '8']
+        java: ['21', '17', '11', '8']
     runs-on: ubuntu-latest
     name: Run test suite with Java ${{ matrix.java }}
     needs: build-and-check
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 1e0cdf2e..b5323ba9 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -30,7 +30,7 @@ jobs:
           persist-credentials: false
       - uses: actions/setup-java@v5
         with:
-          java-version: "17"
+          java-version: "21"
           distribution: "temurin"
           cache: gradle
       - name: Setup node
diff --git a/agent/bin/test_install b/agent/bin/test_install
index 878aed58..7b246551 100755
--- a/agent/bin/test_install
+++ b/agent/bin/test_install
@@ -2,6 +2,8 @@
 
 set -e
 
+(cd ../annotation && ../gradlew jar)
+
 . test/helper.bash
 
 for d in build/fixtures/*; do
@@ -9,5 +11,3 @@ for d in build/fixtures/*; do
   ./mvnw package -quiet -DskipTests -Dcheckstyle.skip=true -Dspring-javaformat.skip=true
   cd -
 done
-
-../gradlew testClasses
diff --git a/agent/bin/test_projects b/agent/bin/test_projects
index 137147f1..0536da56 100755
--- a/agent/bin/test_projects
+++ b/agent/bin/test_projects
@@ -73,7 +73,7 @@ case "${JAVA_VERSION}" in
   1.8*|11.*)
     install_petclinic "land-of-apps/spring-petclinic" old-java-support
     ;;
-  17.*)
+  17.*|21.*)
     # The spring-petclinic main branch now requires Java 25. This is the last commit that supports Java 17.
     install_petclinic "spring-projects/spring-petclinic" "3aa79e3944ab1b626288f5d0629e61643ab8fb4a"
     install_petclinic "spring-petclinic/spring-framework-petclinic"
diff --git a/agent/build.gradle b/agent/build.gradle
index 608bd024..28ac4476 100644
--- a/agent/build.gradle
+++ b/agent/build.gradle
@@ -14,7 +14,6 @@ plugins {
 }
 
 repositories {
-  jcenter()
   mavenCentral()
 }
 
@@ -75,6 +74,7 @@ dependencies {
   testImplementation 'org.junit.jupiter:junit-jupiter'
   testImplementation 'org.junit.jupiter:junit-jupiter-params'
   testImplementation 'org.junit.vintage:junit-vintage-engine'
+  testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
 
   testImplementation 'com.github.stefanbirkner:system-rules:1.19.0'
   testImplementation 'com.github.stefanbirkner:system-lambda:1.2.1'
@@ -85,8 +85,7 @@ dependencies {
 }
 
 compileJava {
-    sourceCompatibility = '1.8'
-    targetCompatibility = '1.8'
+    options.release = 8
 }
 
 jar {
@@ -97,11 +96,11 @@ jar {
   }
 }
 
-apply plugin: 'com.github.johnrengelman.shadow'
+apply plugin: 'com.gradleup.shadow'
 
 shadowJar {
-  baseName = 'appmap'
-  classifier = ''
+  archiveBaseName = 'appmap'
+  archiveClassifier = ''
   minimize() {
     // tinylog computes the dependencies it needs at runtime, so don't exclude
     // anything.
@@ -162,6 +161,7 @@ test {
   dependsOn cleanTest
   exclude 'com/appland/appmap/integration/**'
   // systemProperty "appmap.log.level", "debug"
+  jvmArgs '--add-opens', 'java.base/java.lang=ALL-UNNAMED'
 }
 
 task relocateShadowJar(type: ShadowRelocation) {
@@ -179,16 +179,16 @@ tasks.shadowJar.dependsOn tasks.relocateShadowJar
 
 jacocoTestReport {
   reports {
-    xml.enabled false
-    csv.enabled false
-    html.enabled true
+    xml.required = false
+    csv.required = false
+    html.required = true
   }
 }
 
 // extra artifacts used in publishing
 task sourcesJar(type: Jar) {
   from sourceSets.main.allJava
-  classifier = 'sources'
+  archiveClassifier = 'sources'
 }
 
 // for some reason this block generates empty Javadoc
@@ -198,7 +198,7 @@ javadoc {
 }
 
 task mockJavadocJar(type: Jar) {
-  classifier = 'javadoc'
+  archiveClassifier = 'javadoc'
   from javadoc.destinationDir
 }
 
@@ -212,8 +212,8 @@ publishing {
 
       // 1. coordinates (parameterized)
 
-      groupId publishGroupId
-      artifactId publishArtifactId
+      groupId = publishGroupId
+      artifactId = publishArtifactId
 
       // version defined globally
 
@@ -271,4 +271,4 @@ if (project.hasProperty("signingKey")) {
   }
 }
 
-tasks.publishToMavenLocal.dependsOn(check, integrationTest)
\ No newline at end of file
+tasks.publishToMavenLocal.dependsOn(check, integrationTest)
diff --git a/agent/test/access/MyClass.java b/agent/test/access/MyClass.java
new file mode 100644
index 00000000..724fa061
--- /dev/null
+++ b/agent/test/access/MyClass.java
@@ -0,0 +1,20 @@
+package access;
+
+public class MyClass {
+  public void myMethod() {
+    // do nothing
+  }
+
+  public void callNonPublic() {
+    myPackageMethod();
+    myPrivateMethod();
+  }
+
+  String myPackageMethod() {
+    return "package method";
+  }
+
+  private String myPrivateMethod() {
+    return "private method";
+  }
+}
diff --git a/agent/test/access/RecordPackage.java b/agent/test/access/RecordPackage.java
index 5a9ec27e..ee14035d 100644
--- a/agent/test/access/RecordPackage.java
+++ b/agent/test/access/RecordPackage.java
@@ -1,9 +1,10 @@
+package access;
+
 import java.io.IOException;
 import java.io.OutputStreamWriter;
 
 import com.appland.appmap.record.Recorder;
 import com.appland.appmap.record.Recording;
-import com.appland.appmap.test.fixture.MyClass;
 
 public class RecordPackage {
   public static void main(String[] argv) {
diff --git a/agent/test/access/access.bats b/agent/test/access/access.bats
old mode 100644
new mode 100755
index abe6e730..779c0208
--- a/agent/test/access/access.bats
+++ b/agent/test/access/access.bats
@@ -4,14 +4,17 @@ load '../helper'
 
 sep="$JAVA_PATH_SEPARATOR"
 AGENT_JAR="$(find_agent_jar)"
-wd=$(getcwd)
-test_cp="${wd}/test/access${sep}${wd}/build/classes/java/test"
+
+# Resolves to .../agent/test
+TEST_DIR="$(dirname "$BATS_TEST_DIRNAME")"
+
+# test_cp must include 'test' (for access package) and 'test/access' (for default package)
+test_cp="${TEST_DIR}${sep}${TEST_DIR}/access"
 java_cmd="java -javaagent:'${AGENT_JAR}' -cp '${test_cp}'"
 
 setup() {
-  javac -cp "${AGENT_JAR}${sep}${test_cp}" test/access/*.java
-
-  cd test/access
+  cd "$BATS_TEST_DIRNAME" || exit
+  javac -cp "${AGENT_JAR}" -sourcepath "$TEST_DIR" ./*.java
   _configure_logging
 }
 
@@ -22,7 +25,7 @@ setup() {
 # functionaly it enables is pretty useless, though, so it seems harmless to
 # hijack it.
 @test "testProtected" {
-  local cmd="${java_cmd} RecordPackage"
+  local cmd="${java_cmd} access.RecordPackage"
   [[ $BATS_VERBOSE_RUN == 1 ]] && echo "cmd: $cmd" >&3
 
   # Exactly 4 events means that MyClass.myPrivateMethod was not recorded
@@ -31,7 +34,7 @@ setup() {
 }
 
 @test "testPrivate" {
-  local cmd="${java_cmd} -Dappmap.record.private=true RecordPackage"
+  local cmd="${java_cmd} -Dappmap.record.private=true access.RecordPackage"
   [[ $BATS_VERBOSE_RUN == 1 ]] && echo "cmd: $cmd" >&3
 
   # 6 events means that both myPackageMethod and myPrivateMethod were recorded
@@ -40,7 +43,7 @@ setup() {
 }
 
 @test "outside git repo" {
-  cp -v "$(_top_level)/agent/appmap.yml" "$BATS_TEST_TMPDIR"/.
+  cp -v "appmap.yml" "$BATS_TEST_TMPDIR"/.
   cd "$BATS_TEST_TMPDIR"
 
   # sanity check
@@ -48,7 +51,7 @@ setup() {
   assert_output -p 'not a git repository'
   assert_failure
 
-  local cmd="${java_cmd} RecordPackage"
+  local cmd="${java_cmd} access.RecordPackage"
   [[ $BATS_VERBOSE_RUN == 1 ]] && echo "cmd: $cmd" >&3
   run bash -c "eval \"$cmd\" 2>/dev/null"
   assert_success
diff --git a/agent/test/access/appmap.yml b/agent/test/access/appmap.yml
index e20bd71a..9c3ef4a1 100644
--- a/agent/test/access/appmap.yml
+++ b/agent/test/access/appmap.yml
@@ -1,4 +1,4 @@
 name: test-access
 packages:
-- path: com.appland.appmap.test.fixture
+- path: access
 - path: HelloWorld
\ No newline at end of file
diff --git a/agent/test/event/DisabledValue.java b/agent/test/event/DisabledValue.java
index ef50abce..44df87b5 100644
--- a/agent/test/event/DisabledValue.java
+++ b/agent/test/event/DisabledValue.java
@@ -1,11 +1,11 @@
+package event;
+
 import java.io.IOException;
 import java.io.OutputStreamWriter;
 
 import com.appland.appmap.record.Recorder;
 import com.appland.appmap.record.Recording;
 
-import com.appland.appmap.test.fixture.Example;
-
 public class DisabledValue {
 
   public static void main(String[] argv) {
diff --git a/agent/test/event/Example.java b/agent/test/event/Example.java
new file mode 100644
index 00000000..6cad632f
--- /dev/null
+++ b/agent/test/event/Example.java
@@ -0,0 +1,12 @@
+package event;
+
+public class Example {
+  @Override
+  public String toString() {
+    return "an Example";
+  }
+
+  public Example doSomething(Example other) {
+    return other;
+  }
+}
diff --git a/agent/test/event/appmap.yml b/agent/test/event/appmap.yml
index 63c6f786..bbef530c 100644
--- a/agent/test/event/appmap.yml
+++ b/agent/test/event/appmap.yml
@@ -1,3 +1,3 @@
 name: test-event
 packages:
-- path: com.appland.appmap.test.fixture
+- path: event
diff --git a/agent/test/event/event.bats b/agent/test/event/event.bats
old mode 100644
new mode 100755
index c5c501e7..af9ea103
--- a/agent/test/event/event.bats
+++ b/agent/test/event/event.bats
@@ -2,21 +2,20 @@
 
 load '../helper'
 
-sep="$JAVA_PATH_SEPARATOR"
 AGENT_JAR="$(find_agent_jar)"
-wd=$(getcwd)
-test_cp="${wd}/test/event${sep}${wd}/build/classes/java/test"
-java_cmd="java -javaagent:'${AGENT_JAR}' -cp '${test_cp}'"
 
-setup() {
-  javac -cp "${AGENT_JAR}${sep}${test_cp}" test/event/*.java
+# Resolves to .../agent/test
+TEST_DIR="$(dirname "$BATS_TEST_DIRNAME")"
+java_cmd="java -javaagent:'${AGENT_JAR}' -cp '${TEST_DIR}'"
 
-  cd test/event
+setup() {
+  cd "$BATS_TEST_DIRNAME" || exit
+  javac -cp "${AGENT_JAR}" -sourcepath "$TEST_DIR" ./*.java
   _configure_logging
 }
 
 @test "disabled value" {
-  local cmd="${java_cmd} -Dappmap.event.disableValue=true DisabledValue"
+  local cmd="${java_cmd} -Dappmap.event.disableValue=true event.DisabledValue"
   [[ $BATS_VERBOSE_RUN == 1 ]] && echo "cmd: $cmd" >&3
   
   local output
diff --git a/agent/test/httpcore/httpcore.bats b/agent/test/httpcore/httpcore.bats
old mode 100644
new mode 100755
index 7a511d8c..8cd983c3
--- a/agent/test/httpcore/httpcore.bats
+++ b/agent/test/httpcore/httpcore.bats
@@ -8,12 +8,14 @@
 load '../helper'
 
 setup_file() {
-mkdir -p build/log
+  agent_root="$BATS_TEST_DIRNAME/../.."
+  mkdir -p "$agent_root/build/log"
 
-export LOG="$(getcwd)/build/log/httpcore.log"
-export SERVER_PORT=9090
-export WS_URL=${WS_URL:-http://localhost:9090}
-  cd test/httpcore
+  export LOG="$agent_root/build/log/httpcore.log"
+  export SERVER_PORT=46406
+  export WS_URL=${WS_URL:-http://localhost:${SERVER_PORT}}
+
+  cd "$BATS_TEST_DIRNAME" || exit
   _configure_logging
 
   printf 'getting set up' >&3
diff --git a/agent/test/jdbc/gradle/wrapper/gradle-wrapper.properties b/agent/test/jdbc/gradle/wrapper/gradle-wrapper.properties
index aa991fce..1af9e093 100644
--- a/agent/test/jdbc/gradle/wrapper/gradle-wrapper.properties
+++ b/agent/test/jdbc/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.4.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/agent/test/jdbc/gradlew.bat b/agent/test/jdbc/gradlew.bat
deleted file mode 100644
index ac1b06f9..00000000
--- a/agent/test/jdbc/gradlew.bat
+++ /dev/null
@@ -1,89 +0,0 @@
-@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
-@rem  Gradle startup script for Windows
-@rem
-@rem ##########################################################################
-
-@rem Set local scope for the variables with windows NT shell
-if "%OS%"=="Windows_NT" setlocal
-
-set DIRNAME=%~dp0
-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" "-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 execute
-
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
-
-goto fail
-
-:findJavaFromJavaHome
-set JAVA_HOME=%JAVA_HOME:"=%
-set JAVA_EXE=%JAVA_HOME%/bin/java.exe
-
-if exist "%JAVA_EXE%" goto execute
-
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
-
-goto fail
-
-: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 %*
-
-:end
-@rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
-
-:fail
-rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
-rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
-
-:mainEnd
-if "%OS%"=="Windows_NT" endlocal
-
-:omega
diff --git a/annotation/build.gradle b/annotation/build.gradle
index 228bd7ba..45119a50 100644
--- a/annotation/build.gradle
+++ b/annotation/build.gradle
@@ -12,7 +12,7 @@ plugins {
 }
 
 repositories {
-  jcenter()
+
   mavenCentral()
 }
 
@@ -40,8 +40,7 @@ version = parameterizedVersion ?: ( travisVersionValid ? travisVersion : default
 group = publishGroupId
 
 compileJava {
-    sourceCompatibility = '1.8'
-    targetCompatibility = '1.8'
+    options.release = 8
 }
 
 check {
@@ -50,7 +49,7 @@ check {
 // extra artifacts used in publishing
 task sourcesJar(type: Jar) {
   from sourceSets.main.allJava
-  classifier = 'sources'
+  archiveClassifier = 'sources'
 }
 
 // for some reason this block generates empty Javadoc
@@ -59,7 +58,7 @@ javadoc {
   exclude 'com/appland/**'
 }
 task mockJavadocJar(type: Jar) {
-  classifier = 'javadoc'
+  archiveClassifier = 'javadoc'
   from javadoc.destinationDir
 }
 
@@ -74,8 +73,8 @@ publishing {
 
       // 1. coordinates (parameterized)
 
-      groupId publishGroupId
-      artifactId publishArtifactId
+      groupId = publishGroupId
+      artifactId = publishArtifactId
 
       // version defined globally
 
diff --git a/bats-libs/bats-assert b/bats-libs/bats-assert
new file mode 160000
index 00000000..697471b7
--- /dev/null
+++ b/bats-libs/bats-assert
@@ -0,0 +1 @@
+Subproject commit 697471b7a89d3ab38571f38c6c7c4b460d1f5e35
diff --git a/bats-libs/bats-support b/bats-libs/bats-support
new file mode 160000
index 00000000..0954abb9
--- /dev/null
+++ b/bats-libs/bats-support
@@ -0,0 +1 @@
+Subproject commit 0954abb9925cad550424cebca2b99255d4eabe96
diff --git a/build.gradle b/build.gradle
index da8cc324..8418b551 100644
--- a/build.gradle
+++ b/build.gradle
@@ -7,7 +7,7 @@
  */
 
 plugins {
-  id 'io.github.gradle-nexus.publish-plugin' version '1.1.0'
+  id 'io.github.gradle-nexus.publish-plugin' version '2.0.0'
   id "com.dorongold.task-tree" version "2.1.0"
 }
 
@@ -49,4 +49,8 @@ subprojects {
     toolVersion = "9.3"
     configFile = rootProject.file("config/checkstyle/checkstyle.xml")
   }
+
+  tasks.withType(JavaCompile) {
+    options.compilerArgs << "-Xlint:-options"
+  }
 }
diff --git a/buildSrc/build.gradle b/buildSrc/build.gradle
index 874a521b..3ed1e411 100644
--- a/buildSrc/build.gradle
+++ b/buildSrc/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
   repositories {
-    jcenter()
+    mavenCentral()
     maven {
-      url "https://plugins.gradle.org/m2/"
+      url = "https://plugins.gradle.org/m2/"
     }
   }
   dependencies {
-    classpath 'gradle.plugin.com.github.johnrengelman:shadow:7.1.2'
+    classpath 'com.gradleup.shadow:shadow-gradle-plugin:9.3.1'
   }
 }
 
@@ -16,14 +16,14 @@ plugins {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
     maven {
-      url "https://plugins.gradle.org/m2/"
+      url = "https://plugins.gradle.org/m2/"
     }
   }
 
 dependencies {
-  implementation 'gradle.plugin.com.github.johnrengelman:shadow:7.1.2'
+  implementation 'com.gradleup.shadow:shadow-gradle-plugin:9.3.1'
 }
 
 
diff --git a/buildSrc/src/main/groovy/com/appland/tasks/ShadowRelocation.groovy b/buildSrc/src/main/groovy/com/appland/tasks/ShadowRelocation.groovy
index 7f93a9ec..2eb073f6 100644
--- a/buildSrc/src/main/groovy/com/appland/tasks/ShadowRelocation.groovy
+++ b/buildSrc/src/main/groovy/com/appland/tasks/ShadowRelocation.groovy
@@ -25,7 +25,7 @@ class ShadowRelocation extends DefaultTask {
 
   @InputFiles @Optional
   List<Configuration> getConfigurations() {
-      return target.configurations
+      return target.configurations.get().toList()
   }
 
   @TaskAction
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 41d9927a..f8e1ee31 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 aa991fce..23449a2b 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.4.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.2.1-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
index 1b6c7873..adff685a 100755
--- a/gradlew
+++ b/gradlew
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 #
-# Copyright © 2015-2021 the original authors.
+# Copyright © 2015 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -15,6 +15,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 
 ##############################################################################
 #
@@ -55,7 +57,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -80,13 +82,11 @@ do
     esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${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" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
@@ -114,7 +114,6 @@ case "$( uname )" in                #(
   NONSTOP* )        nonstop=true ;;
 esac
 
-CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 
 # Determine the Java command to use to start the JVM.
@@ -133,22 +132,29 @@ location of your Java installation."
     fi
 else
     JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
+    fi
 fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
     case $MAX_FD in #(
       max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
         MAX_FD=$( ulimit -H -n ) ||
             warn "Could not query maximum file descriptor limit"
     esac
     case $MAX_FD in  #(
       '' | soft) :;; #(
       *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
         ulimit -n "$MAX_FD" ||
             warn "Could not set maximum file descriptor limit to $MAX_FD"
     esac
@@ -165,7 +171,6 @@ fi
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
     APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
     JAVACMD=$( cygpath --unix "$JAVACMD" )
 
@@ -193,18 +198,27 @@ if "$cygwin" || "$msys" ; then
     done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# 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" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
         "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
         "$@"
 
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
 # Use "xargs" to parse quoted args.
 #
 # With -n1 it outputs one arg per line, with the quotes and backslashes removed.
diff --git a/gradlew.bat b/gradlew.bat
index ac1b06f9..e509b2dd 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -13,8 +13,10 @@
 @rem See the License for the specific language governing permissions and
 @rem limitations under the License.
 @rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +27,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -40,13 +43,13 @@ if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,32 +59,33 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
 :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 %*
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/runtime/build.gradle b/runtime/build.gradle
index b134b5dd..aaeac339 100644
--- a/runtime/build.gradle
+++ b/runtime/build.gradle
@@ -3,13 +3,11 @@ plugins {
 }
 
 repositories {
-  jcenter()
   mavenCentral()
 }
 
 compileJava {
-    sourceCompatibility = '1.8'
-    targetCompatibility = '1.8'
+    options.release = 8
 }
 
 // Don't put dependencies here.