diff --git a/build.gradle b/build.gradle
deleted file mode 100644
index ad346b41..00000000
--- a/build.gradle
+++ /dev/null
@@ -1,283 +0,0 @@
-/*
- * Copyright 2019 Aiven Oy and http-connector-for-apache-kafka project contributors
- *
- * 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
- *
- * http://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.
- */
-
-plugins {
-    // https://docs.gradle.org/current/userguide/java_library_plugin.html
-    id 'java-library'
-
-    // https://docs.gradle.org/current/userguide/distribution_plugin.html
-    id 'distribution'
-
-    // https://docs.gradle.org/current/userguide/checkstyle_plugin.html
-    id 'checkstyle'
-
-    // https://docs.gradle.org/current/userguide/idea_plugin.html
-    id 'idea'
-
-    // https://plugins.gradle.org/plugin/nebula.lint
-    id "nebula.lint" version "19.0.1"
-
-    // https://plugins.gradle.org/plugin/com.github.spotbugs
-    id "com.github.spotbugs" version "6.0.7"
-
-    // https://plugins.gradle.org/plugin/com.diffplug.gradle.spotless
-    id "com.diffplug.spotless" version "6.25.0"
-}
-
-repositories {
-    mavenCentral()
-    maven {
-        url "https://packages.confluent.io/maven"
-    }
-}
-
-sourceCompatibility = JavaVersion.VERSION_11
-targetCompatibility = JavaVersion.VERSION_11
-
-wrapper {
-    distributionType = 'ALL'
-    doLast {
-        def sha256Sum = new String(new URL("${distributionUrl}.sha256").bytes)
-        propertiesFile << "distributionSha256Sum=${sha256Sum}\n"
-        println "Added checksum to wrapper properties"
-    }
-}
-
-ext {
-    moduleName = "io.aiven.kafka.connect.http"
-
-    avroVersion = "1.9.2" // Version 1.9.2 brings Jackson 2.10.2 package for Avro
-    confluentPlatformVersion = "6.0.2" // For compatibility tests use version 6.0.2 to match Kafka 2.6.
-                                       // NOTE: Confluent Platform v6.0.3 has a dependency mismatch issue.
-    hamcrestVersion = "2.2"
-    jacksonVersion = "2.16.1" // This Jackson is used in the tests.
-    jupiterVersion = "5.10.1"
-    kafkaVersion = '2.6.3'
-    jettyVersion = "9.4.51.v20230217"
-    junit4Version = "4.13.2"
-    jsr305Version = "3.0.2"
-    log4jVersion = "2.20.0"
-    mockitoVersion = '5.6.0'
-    servletVersion = "4.0.1"
-    slf4japiVersion = "1.7.36"
-    spotbugsAnnotationsVersion = "4.7.3"
-    testcontainersVersion = '1.19.0'
-    assertjVersion = "3.25.2"
-    awaitilityVersion = "4.2.0"
-}
-
-distributions {
-    main {
-        contents {
-            from jar
-            from configurations.runtimeClasspath
-        }
-    }
-}
-
-sourceSets {
-    integrationTest {
-        java.srcDir file('src/integration-test/java')
-        resources.srcDir file('src/integration-test/resources')
-        compileClasspath += sourceSets.main.output + configurations.testRuntimeClasspath
-        runtimeClasspath += output + compileClasspath
-    }
-}
-
-idea {
-    module {
-        testSources.from(sourceSets.integrationTest.java.srcDirs)
-        testSources.from(sourceSets.integrationTest.resources.srcDirs)
-    }
-}
-
-configurations {
-    integrationTestImplementation.extendsFrom testImplementation
-    integrationTestRuntimeOnly.extendsFrom testRuntimeOnly
-}
-
-dependencies {
-    compileOnly "org.apache.kafka:connect-api:$kafkaVersion"
-    compileOnly "org.apache.kafka:connect-json:$kafkaVersion"
-    compileOnly "org.apache.kafka:kafka-clients:$kafkaVersion"
-
-    // For Spotbugs suppressions
-    compileOnly "com.github.spotbugs:spotbugs-annotations:$spotbugsAnnotationsVersion"
-    compileOnly "com.google.code.findbugs:jsr305:$jsr305Version"
-
-    implementation "com.fasterxml.jackson.core:jackson-core:$jacksonVersion"
-    implementation "com.fasterxml.jackson.core:jackson-databind:$jacksonVersion"
-    implementation "org.slf4j:slf4j-api:$slf4japiVersion"
-
-    testRuntimeOnly "org.apache.kafka:connect-json:$kafkaVersion"
-    testRuntimeOnly "org.apache.logging.log4j:log4j-slf4j-impl:$log4jVersion"
-    testRuntimeOnly "org.junit.jupiter:junit-jupiter:$jupiterVersion"
-
-    testImplementation "org.apache.kafka:connect-api:$kafkaVersion"
-    testImplementation "org.junit.jupiter:junit-jupiter-api:$jupiterVersion"
-    testImplementation "org.junit.jupiter:junit-jupiter-params:$jupiterVersion"
-    testImplementation "org.mockito:mockito-core:$mockitoVersion"
-    testImplementation "org.mockito:mockito-junit-jupiter:$mockitoVersion"
-    testImplementation "org.assertj:assertj-core:$assertjVersion"
-
-    integrationTestRuntimeOnly "io.confluent:kafka-avro-serializer:$confluentPlatformVersion"
-    integrationTestRuntimeOnly "io.confluent:kafka-connect-avro-converter:$confluentPlatformVersion"
-    integrationTestRuntimeOnly "io.confluent:kafka-json-serializer:$confluentPlatformVersion"
-    integrationTestRuntimeOnly "org.junit.jupiter:junit-jupiter:$jupiterVersion"
-    integrationTestRuntimeOnly "org.apache.logging.log4j:log4j-slf4j-impl:$log4jVersion"
-
-    integrationTestImplementation "org.apache.kafka:connect-runtime:$kafkaVersion"
-    integrationTestImplementation "com.fasterxml.jackson.core:jackson-annotations:$jacksonVersion"
-    integrationTestImplementation "javax.servlet:javax.servlet-api:$servletVersion"
-    integrationTestImplementation "org.apache.avro:avro:$avroVersion"
-    integrationTestImplementation "org.apache.kafka:connect-runtime:$kafkaVersion"
-    integrationTestImplementation "org.eclipse.jetty:jetty-http:$jettyVersion"
-    integrationTestImplementation "org.eclipse.jetty:jetty-server:$jettyVersion"
-    integrationTestImplementation "org.eclipse.jetty:jetty-util:$jettyVersion"
-    integrationTestImplementation "junit:junit:$junit4Version" // This is for testcontainers
-    integrationTestImplementation "org.testcontainers:junit-jupiter:$testcontainersVersion"
-    integrationTestImplementation "org.testcontainers:kafka:$testcontainersVersion" // this is not Kafka version
-    integrationTestImplementation "org.testcontainers:testcontainers:$testcontainersVersion"
-    integrationTestImplementation "org.awaitility:awaitility:$awaitilityVersion"
-
-    // Make test utils from 'test' available in 'integration-test'
-    integrationTestImplementation sourceSets.test.output
-}
-
-checkstyle {
-    toolVersion '10.12.0'
-}
-
-compileJava {
-    // Enable modules.
-    inputs.property('moduleName', moduleName)
-    doFirst {
-        options.compilerArgs = [
-                '--module-path', classpath.asPath
-        ]
-        classpath = files()
-    }
-}
-
-test {
-    useJUnitPlatform {
-        includeEngines 'junit-jupiter'
-    }
-}
-
-tasks.register('integrationTest', Test) {
-    description = 'Runs the integration tests.'
-    group = 'verification'
-    testClassesDirs = sourceSets.integrationTest.output.classesDirs
-    classpath = sourceSets.integrationTest.runtimeClasspath
-
-    // defines testing order
-    shouldRunAfter test
-    // requires archive for connect runner
-    dependsOn distTar
-
-    useJUnitPlatform()
-
-    // Run always.
-    outputs.upToDateWhen { false }
-
-    // Pass the distribution file path to the tests.
-    systemProperty("integration-test.distribution.file.path", distTar.archiveFile.get().asFile.path)
-}
-
-tasks.javadoc {
-    // disable missing javadoc lint and show only warning and error messages
-    options.addStringOption('Xdoclint:all,-missing', '-quiet')
-}
-
-processResources {
-    filesMatching('http-connector-for-apache-kafka-version.properties') {
-        expand(version: version)
-    }
-}
-
-jar {
-    manifest {
-        attributes(
-                'Version': "${getArchiveVersion().get()}"
-        )
-    }
-}
-
-tasks.register('connectorConfigDoc') {
-    description = "Generates the connector's configuration documentation."
-    group = "documentation"
-    dependsOn "classes"
-
-    doLast {
-        javaexec {
-            main = "io.aiven.kafka.connect.http.config.HttpSinkConfig"
-            classpath = sourceSets.main.runtimeClasspath + sourceSets.main.compileClasspath
-            standardOutput = new FileOutputStream("$projectDir/docs/sink-connector-config-options.rst")
-        }
-    }
-}
-
-spotless {
-    format "xml", {
-        target "**/*.xml"
-        targetExclude ".*/**", "gradle/wrapper/**"
-        eclipseWtp("xml").configFile("${project.rootDir}/config/spotless-eclipse-wtp-xml.prefs")
-        endWithNewline()
-    }
-
-    format "misc", {
-        target "**/*.gradle", "**/*.md", "**/*.properties"
-        targetExclude ".*/**", "gradle/wrapper/**"
-        endWithNewline()
-        indentWithSpaces()
-        trimTrailingWhitespace()
-    }
-}
-
-spotbugs {
-    toolVersion = "4.7.3"
-    excludeFilter = file("${project.rootDir}/config/spotbugs-exclude.xml")
-}
-spotbugsMain {
-    reports {
-        html {
-            enabled = true
-            stylesheet = 'fancy-hist.xsl'
-        }
-    }
-}
-spotbugsTest {
-    reports {
-        html {
-            enabled = true
-            stylesheet = 'fancy-hist.xsl'
-        }
-    }
-}
-spotbugsIntegrationTest {
-    reports {
-        html {
-            enabled = true
-            stylesheet = 'fancy-hist.xsl'
-        }
-    }
-}
-
-gradleLint.alwaysRun = false
-gradleLint {
-    rules  = ['all-dependency']
-}
diff --git a/build.gradle.kts b/build.gradle.kts
new file mode 100644
index 00000000..a0fdabc5
--- /dev/null
+++ b/build.gradle.kts
@@ -0,0 +1,248 @@
+import com.diffplug.spotless.extra.wtp.EclipseWtpFormatterStep
+import com.github.spotbugs.snom.SpotBugsTask
+import java.io.FileOutputStream
+import java.net.URL
+
+/*
+ * Copyright 2019 Aiven Oy and http-connector-for-apache-kafka project contributors
+ *
+ * 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
+ *
+ * http://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.
+ */
+
+plugins {
+    // https://docs.gradle.org/current/userguide/java_library_plugin.html
+    `java-library`
+
+    // https://docs.gradle.org/current/userguide/distribution_plugin.html
+    distribution
+
+    // https://docs.gradle.org/current/userguide/checkstyle_plugin.html
+    checkstyle
+
+    // https://docs.gradle.org/current/userguide/idea_plugin.html
+    idea
+
+    // https://plugins.gradle.org/plugin/com.github.spotbugs
+    id("com.github.spotbugs") version "6.0.7"
+
+    // https://plugins.gradle.org/plugin/com.diffplug.gradle.spotless
+    id("com.diffplug.spotless") version "6.25.0"
+}
+
+repositories {
+    mavenCentral()
+    maven("https://packages.confluent.io/maven")
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_11
+    targetCompatibility = JavaVersion.VERSION_11
+}
+
+tasks.wrapper {
+    distributionType = Wrapper.DistributionType.ALL
+    doLast {
+        val sha256Sum = URL("$distributionUrl.sha256").readText()
+        propertiesFile.appendText("distributionSha256Sum=${sha256Sum}\n")
+        println("Added checksum to wrapper properties")
+    }
+}
+
+val moduleName = "io.aiven.kafka.connect.http"
+
+val avroVersion = "1.9.2" // Version 1.9.2 brings Jackson 2.10.2 package for Avro
+val confluentPlatformVersion = "6.0.2" // For compatibility tests use version 6.0.2 to match Kafka 2.6.
+// NOTE: Confluent Platform v6.0.3 has a dependency mismatch issue.
+val hamcrestVersion = "2.2"
+val jacksonVersion = "2.16.1" // This Jackson is used in the tests.
+val jupiterVersion = "5.10.1"
+val kafkaVersion = "2.6.3"
+val jettyVersion = "9.4.51.v20230217"
+val junit4Version = "4.13.2"
+val jsr305Version = "3.0.2"
+val log4jVersion = "2.20.0"
+val mockitoVersion = "5.10.0"
+val servletVersion = "4.0.1"
+val slf4japiVersion = "1.7.36"
+val spotbugsAnnotationsVersion = "4.8.2"
+val testcontainersVersion = "1.19.4"
+val assertjVersion = "3.25.2"
+val awaitilityVersion = "4.2.0"
+
+distributions {
+    named("main") {
+        contents {
+            from(tasks.jar)
+            from(configurations.runtimeClasspath)
+        }
+    }
+}
+
+sourceSets {
+    create("integrationTest") {
+        java.srcDir(file("src/integration-test/java"))
+        resources.srcDir(file("src/integration-test/resources"))
+        compileClasspath += sourceSets.main.get().output + configurations.testRuntimeClasspath.get()
+        runtimeClasspath += output + compileClasspath
+    }
+}
+
+idea {
+    module {
+        testSources.from(project.sourceSets["integrationTest"].java.srcDirs)
+        testSources.from(project.sourceSets["integrationTest"].resources.srcDirs)
+    }
+}
+
+val integrationTestImplementation: Configuration by configurations.getting {
+    extendsFrom(configurations["testImplementation"])
+}
+
+val integrationTestRuntimeOnly: Configuration by configurations.getting {
+    extendsFrom(configurations["testRuntimeOnly"])
+}
+
+dependencies {
+    compileOnly("org.apache.kafka:connect-api:$kafkaVersion")
+    compileOnly("org.apache.kafka:connect-json:$kafkaVersion")
+    compileOnly("org.apache.kafka:kafka-clients:$kafkaVersion")
+
+    // For Spotbugs suppressions
+    compileOnly("com.github.spotbugs:spotbugs-annotations:$spotbugsAnnotationsVersion")
+    compileOnly("com.google.code.findbugs:jsr305:$jsr305Version")
+
+    implementation("com.fasterxml.jackson.core:jackson-core:$jacksonVersion")
+    implementation("com.fasterxml.jackson.core:jackson-databind:$jacksonVersion")
+    implementation("org.slf4j:slf4j-api:$slf4japiVersion")
+
+    testRuntimeOnly("org.apache.kafka:connect-json:$kafkaVersion")
+    testRuntimeOnly("org.apache.logging.log4j:log4j-slf4j-impl:$log4jVersion")
+    testRuntimeOnly("org.junit.jupiter:junit-jupiter:$jupiterVersion")
+
+    testImplementation("org.apache.kafka:connect-api:$kafkaVersion")
+    testImplementation("org.junit.jupiter:junit-jupiter-api:$jupiterVersion")
+    testImplementation("org.junit.jupiter:junit-jupiter-params:$jupiterVersion")
+    testImplementation("org.mockito:mockito-core:$mockitoVersion")
+    testImplementation("org.mockito:mockito-junit-jupiter:$mockitoVersion")
+    testImplementation("org.assertj:assertj-core:$assertjVersion")
+
+    integrationTestRuntimeOnly("io.confluent:kafka-avro-serializer:$confluentPlatformVersion")
+    integrationTestRuntimeOnly("io.confluent:kafka-connect-avro-converter:$confluentPlatformVersion")
+    integrationTestRuntimeOnly("io.confluent:kafka-json-serializer:$confluentPlatformVersion")
+    integrationTestRuntimeOnly("org.junit.jupiter:junit-jupiter:$jupiterVersion")
+    integrationTestRuntimeOnly("org.apache.logging.log4j:log4j-slf4j-impl:$log4jVersion")
+
+    integrationTestImplementation("org.apache.kafka:connect-runtime:$kafkaVersion")
+    integrationTestImplementation("com.fasterxml.jackson.core:jackson-annotations:$jacksonVersion")
+    integrationTestImplementation("javax.servlet:javax.servlet-api:$servletVersion")
+    integrationTestImplementation("org.apache.avro:avro:$avroVersion")
+    integrationTestImplementation("org.apache.kafka:connect-runtime:$kafkaVersion")
+    integrationTestImplementation("org.eclipse.jetty:jetty-http:$jettyVersion")
+    integrationTestImplementation("org.eclipse.jetty:jetty-server:$jettyVersion")
+    integrationTestImplementation("org.eclipse.jetty:jetty-util:$jettyVersion")
+    integrationTestImplementation("junit:junit:$junit4Version") // This is for testcontainers
+    integrationTestImplementation("org.testcontainers:junit-jupiter:$testcontainersVersion")
+    integrationTestImplementation("org.testcontainers:kafka:$testcontainersVersion") // this is not Kafka version
+    integrationTestImplementation("org.testcontainers:testcontainers:$testcontainersVersion")
+    integrationTestImplementation("org.awaitility:awaitility:$awaitilityVersion")
+
+    // Make test utils from "test" available in "integration-test"
+    integrationTestImplementation(sourceSets["test"].output)
+}
+
+checkstyle {
+    toolVersion = "8.25"
+}
+
+tasks.compileJava {
+    inputs.property("moduleName", moduleName)
+    doFirst {
+        options.compilerArgs = listOf("--module-path", classpath.asPath)
+        classpath = files()
+    }
+}
+
+tasks {
+    create("integrationTest", Test::class) {
+        description = "Runs the integration tests."
+        group = "verification"
+        testClassesDirs = sourceSets["integrationTest"].output.classesDirs
+        classpath = sourceSets["integrationTest"].runtimeClasspath
+        dependsOn("test", "distTar")
+        useJUnitPlatform()
+        outputs.upToDateWhen { false }
+        systemProperty("integration-test.distribution.file.path", distTar.get().archiveFile.get().asFile.path)
+    }
+}
+
+tasks.test {
+    useJUnitPlatform {
+        includeEngines("junit-jupiter")
+    }
+}
+
+tasks.processResources {
+    filesMatching("http-connector-for-apache-kafka-version.properties") {
+        expand(mapOf("version" to version))
+    }
+}
+
+tasks.jar {
+    manifest {
+        attributes(mapOf("Version" to archiveVersion.get()))
+    }
+}
+
+tasks.register("connectorConfigDoc") {
+    description = "Generates the connector's configuration documentation."
+    group = "documentation"
+    dependsOn("classes")
+    doLast {
+        project.javaexec {
+            mainClass = "io.aiven.kafka.connect.http.config.HttpSinkConfig"
+            classpath = sourceSets.main.get().runtimeClasspath + sourceSets.main.get().compileClasspath
+            standardOutput = FileOutputStream("$projectDir/docs/sink-connector-config-options.rst")
+        }
+    }
+}
+
+spotless {
+    format("xml") {
+        target("**/*.xml")
+        targetExclude(".*/**", "gradle/wrapper/**")
+        eclipseWtp(EclipseWtpFormatterStep.XML).configFile("${project.rootDir}/config/spotless-eclipse-wtp-xml.prefs")
+        endWithNewline()
+    }
+
+    format("misc") {
+        target("**/*.gradle", "**/*.md", "**/*.properties")
+        targetExclude(".*/**", "gradle/wrapper/**")
+        endWithNewline()
+        indentWithSpaces()
+        trimTrailingWhitespace()
+    }
+    kotlinGradle {
+        ktlint()
+    }
+}
+
+spotbugs {
+    toolVersion = "4.8.3"
+    excludeFilter = file("${project.rootDir}/config/spotbugs-exclude.xml")
+}
+tasks.withType<SpotBugsTask>().configureEach {
+    reports.create("html") {
+        required = true
+        setStylesheet("fancy-hist.xsl")
+    }
+}
diff --git a/docs/sink-connector-config-options.rst b/docs/sink-connector-config-options.rst
index f0cdcfea..5a905367 100644
--- a/docs/sink-connector-config-options.rst
+++ b/docs/sink-connector-config-options.rst
@@ -190,7 +190,7 @@ Delivery
   The time in milliseconds to wait following an error before a retry attempt is made.
 
   * Type: int
-  * Default: 3000
+  * Default: 3000 (3 seconds)
   * Valid Values: [0,...]
   * Importance: medium
 
@@ -205,4 +205,14 @@ Timeout
   * Valid Values: [1,...]
   * Importance: low
 
+Errors Handling
+^^^^^^^^^^^^^^^
+
+``errors.tolerance``
+  Optional errors.tolerance setting. Defaults to "none".
+
+  * Type: string
+  * Default: null
+  * Importance: low
+
 
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 41d9927a..d64cd491 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 ece8b00a..e554d847 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,8 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.6-all.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionSha256Sum=5625a0ae20fe000d9225d000b36909c7a0e0e8dda61c19b12da769add847c975
+distributionSha256Sum=85719317abd2112f021d4f41f09ec370534ba288432065f4b477b6a3b652910d
diff --git a/gradlew b/gradlew
index 1b6c7873..1aa94a42 100755
--- a/gradlew
+++ b/gradlew
@@ -55,7 +55,7 @@
 #       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/subprojects/plugins/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 +80,11 @@ 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 "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
@@ -133,22 +131,29 @@ 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 $MAX_FD"
     esac
@@ -193,11 +198,15 @@ if "$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, 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=$APP_BASE_NAME" \
@@ -205,6 +214,12 @@ set -- \
         org.gradle.wrapper.GradleWrapperMain \
         "$@"
 
+# 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..7101f8e4 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 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 +41,13 @@ 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
 
@@ -56,11 +57,11 @@ 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
 
@@ -75,13 +76,15 @@ set CLASSPATH=%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/settings.gradle b/settings.gradle
deleted file mode 100644
index 08ba9124..00000000
--- a/settings.gradle
+++ /dev/null
@@ -1 +0,0 @@
-rootProject.name = 'http-connector-for-apache-kafka'
diff --git a/settings.gradle.kts b/settings.gradle.kts
new file mode 100644
index 00000000..6b76db6c
--- /dev/null
+++ b/settings.gradle.kts
@@ -0,0 +1 @@
+rootProject.name = "http-connector-for-apache-kafka"
diff --git a/src/main/java/io/aiven/kafka/connect/http/config/HttpSinkConfig.java b/src/main/java/io/aiven/kafka/connect/http/config/HttpSinkConfig.java
index 5abd7f3e..38604513 100644
--- a/src/main/java/io/aiven/kafka/connect/http/config/HttpSinkConfig.java
+++ b/src/main/java/io/aiven/kafka/connect/http/config/HttpSinkConfig.java
@@ -37,7 +37,7 @@
 
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 
-public class HttpSinkConfig extends AbstractConfig {
+public final class HttpSinkConfig extends AbstractConfig {
     private static final String CONNECTION_GROUP = "Connection";
     private static final String HTTP_URL_CONFIG = "http.url";
     private static final String HTTP_PROXY_HOST = "http.proxy.host";