diff --git a/build.gradle b/build.gradle
index 103dce9..994f436 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,108 +1,35 @@
-
 plugins {
-    id "org.sonarqube" version "2.8"
+    id "de.marcphilipp.nexus-publish" version "0.4.0"
     id "io.codearte.nexus-staging" version "0.21.1"
 }
 
+wrapper {
+    gradleVersion = "${project.property('gradle.wrapper.version')}"
+    distributionType = Wrapper.DistributionType.ALL
+}
+
+ext {
+    user = 'xbib'
+    name = 'metrics'
+    description = 'A stripped-down and modified version of Coda Hale Metrics'
+    inceptionYear = '2016'
+    url = 'https://github.com/' + user + '/' + name
+    scmUrl = 'https://github.com/' + user + '/' + name
+    scmConnection = 'scm:git:git://github.com/' + user + '/' + name + '.git'
+    scmDeveloperConnection = 'scm:git:ssh://git@github.com:' + user + '/' + name + '.git'
+    issueManagementSystem = 'Github'
+    issueManagementUrl = ext.scmUrl + '/issues'
+    licenseName = 'The Apache License, Version 2.0'
+    licenseUrl = 'http://www.apache.org/licenses/LICENSE-2.0.txt'
+}
+
+
 subprojects {
-
-    apply plugin: 'java'
-    apply plugin: 'maven'
-
-    dependencies {
-        testCompile "junit:junit:${project.property('junit.version')}"
-        testCompile "org.apache.logging.log4j:log4j-core:${project.property('log4j.version')}"
-        testCompile "org.apache.logging.log4j:log4j-slf4j-impl:${project.property('log4j.version')}"
-    }
-
-    compileJava {
-        sourceCompatibility = JavaVersion.VERSION_11
-        targetCompatibility = JavaVersion.VERSION_11
-    }
-    compileTestJava {
-        sourceCompatibility = JavaVersion.VERSION_11
-        targetCompatibility = JavaVersion.VERSION_11
-    }
-    tasks.withType(JavaCompile) {
-        options.compilerArgs << "-Xlint:all"
-    }
-    
-    task javadocJar(type: Jar, dependsOn: classes) {
-        from javadoc
-        classifier 'javadoc'
-    }
-    
-    task sourcesJar(type: Jar, dependsOn: classes) {
-        from sourceSets.main.allSource
-        classifier 'sources'
-    }
-    
-    artifacts {
-        archives javadocJar, sourcesJar
-    }
-
-    ext {
-        user = 'jprante'
-        name = 'metrics'
-        description = 'A stripped-down and modified version of Coda Hale Metrics'
-        scmUrl = 'https://github.com/' + user + '/' + name
-        scmConnection = 'scm:git:git://github.com/' + user + '/' + name + '.git'
-        scmDeveloperConnection = 'scm:git:git://github.com/' + user + '/' + name + '.git'
-    }
-
-    task sonaTypeUpload(type: Upload) {
-        group = 'publish'
-        configuration = configurations.archives
-        uploadDescriptor = true
-        repositories {
-            if (project.hasProperty('ossrhUsername')) {
-                mavenDeployer {
-                    beforeDeployment { MavenDeployment deployment -> signing.signPom(deployment) }
-                    repository(url: 'https://oss.sonatype.org/service/local/staging/deploy/maven2') {
-                        authentication(userName: ossrhUsername, password: ossrhPassword)
-                    }
-                    snapshotRepository(url: 'https://oss.sonatype.org/content/repositories/snapshots') {
-                        authentication(userName: ossrhUsername, password: ossrhPassword)
-                    }
-                    pom.project {
-                        groupId project.group
-                        artifactId project.name
-                        version project.version
-                        name project.name
-                        description description
-                        packaging 'jar'
-                        inceptionYear '2016'
-                        url scmUrl
-                        organization {
-                            name 'xbib'
-                            url 'http://xbib.org'
-                        }
-                        developers {
-                            developer {
-                                id user
-                                name 'Jörg Prante'
-                                email 'joergprante@gmail.com'
-                                url 'https://github.com/jprante'
-                            }
-                        }
-                        scm {
-                            url scmUrl
-                            connection scmConnection
-                            developerConnection scmDeveloperConnection
-                        }
-                        licenses {
-                            license {
-                                name 'The Apache License, Version 2.0'
-                                url 'http://www.apache.org/licenses/LICENSE-2.0.txt'
-                            }
-                        }
-                    }
-                }
-            }
-        }
-    }
+    apply plugin: 'java-library'
+    apply from: rootProject.file('gradle/ide/idea.gradle')
+    apply from: rootProject.file('gradle/compile/java.gradle')
+    apply from: rootProject.file('gradle/test/junit5.gradle')
+    apply from: rootProject.file('gradle/publishing/publication.gradle')
 }
 
-nexusStaging {
-    packageGroup = "org.xbib"
-}
+apply from: rootProject.file('gradle/publishing/sonatype.gradle')
diff --git a/gradle.properties b/gradle.properties
index d240468..89d98f0 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,7 +1,5 @@
 group = org.xbib
 name = metrics
-version = 2.0.0
+version = 2.1.0
 
-# test
-log4j.version = 2.12.1
-junit.version = 4.12
+gradle.wrapper.version = 6.4.1
diff --git a/gradle/compile/java.gradle b/gradle/compile/java.gradle
new file mode 100644
index 0000000..a9d76ce
--- /dev/null
+++ b/gradle/compile/java.gradle
@@ -0,0 +1,35 @@
+
+apply plugin: 'java-library'
+
+java {
+    modularity.inferModulePath.set(true)
+}
+
+compileJava {
+    sourceCompatibility = JavaVersion.VERSION_11
+    targetCompatibility = JavaVersion.VERSION_11
+}
+
+compileTestJava {
+    sourceCompatibility = JavaVersion.VERSION_11
+    targetCompatibility = JavaVersion.VERSION_11
+}
+
+jar {
+    manifest {
+        attributes('Implementation-Version': project.version)
+    }
+}
+
+task sourcesJar(type: Jar, dependsOn: classes) {
+    classifier 'sources'
+    from sourceSets.main.allSource
+}
+
+task javadocJar(type: Jar, dependsOn: javadoc) {
+    classifier 'javadoc'
+}
+
+artifacts {
+    archives sourcesJar, javadocJar
+}
\ No newline at end of file
diff --git a/gradle/documentation/asciidoc.gradle b/gradle/documentation/asciidoc.gradle
new file mode 100644
index 0000000..87ba22e
--- /dev/null
+++ b/gradle/documentation/asciidoc.gradle
@@ -0,0 +1,55 @@
+apply plugin: 'org.xbib.gradle.plugin.asciidoctor'
+
+configurations {
+    asciidoclet
+}
+
+dependencies {
+    asciidoclet "org.asciidoctor:asciidoclet:${project.property('asciidoclet.version')}"
+}
+
+
+asciidoctor {
+    backends 'html5'
+    outputDir = file("${rootProject.projectDir}/docs")
+    separateOutputDirs = false
+    attributes 'source-highlighter': 'coderay',
+            idprefix: '',
+            idseparator: '-',
+            toc: 'left',
+            doctype: 'book',
+            icons: 'font',
+            encoding: 'utf-8',
+            sectlink: true,
+            sectanchors: true,
+            linkattrs: true,
+            imagesdir: 'img',
+            stylesheet: "${projectDir}/src/docs/asciidoc/css/foundation.css"
+}
+
+
+/*javadoc {
+options.docletpath = configurations.asciidoclet.files.asType(List)
+options.doclet = 'org.asciidoctor.Asciidoclet'
+//options.overview = "src/docs/asciidoclet/overview.adoc"
+options.addStringOption "-base-dir", "${projectDir}"
+options.addStringOption "-attribute",
+        "name=${project.name},version=${project.version},title-link=https://github.com/xbib/${project.name}"
+configure(options) {
+    noTimestamp = true
+}
+}*/
+
+
+/*javadoc {
+    options.docletpath = configurations.asciidoclet.files.asType(List)
+    options.doclet = 'org.asciidoctor.Asciidoclet'
+    options.overview = "${rootProject.projectDir}/src/docs/asciidoclet/overview.adoc"
+    options.addStringOption "-base-dir", "${projectDir}"
+    options.addStringOption "-attribute",
+            "name=${project.name},version=${project.version},title-link=https://github.com/xbib/${project.name}"
+    options.destinationDirectory(file("${projectDir}/docs/javadoc"))
+    configure(options) {
+        noTimestamp = true
+    }
+}*/
diff --git a/gradle/ide/idea.gradle b/gradle/ide/idea.gradle
new file mode 100644
index 0000000..64e2167
--- /dev/null
+++ b/gradle/ide/idea.gradle
@@ -0,0 +1,13 @@
+apply plugin: 'idea'
+
+idea {
+    module {
+        outputDir file('build/classes/java/main')
+        testOutputDir file('build/classes/java/test')
+    }
+}
+
+if (project.convention.findPlugin(JavaPluginConvention)) {
+    //sourceSets.main.output.classesDirs = file("build/classes/java/main")
+    //sourceSets.test.output.classesDirs = file("build/classes/java/test")
+}
diff --git a/gradle/publishing/publication.gradle b/gradle/publishing/publication.gradle
new file mode 100644
index 0000000..c35fcb9
--- /dev/null
+++ b/gradle/publishing/publication.gradle
@@ -0,0 +1,64 @@
+
+apply plugin: "de.marcphilipp.nexus-publish"
+
+publishing {
+    publications {
+        mavenJava(MavenPublication) {
+            from components.java
+            artifact sourcesJar
+            artifact javadocJar
+            pom {
+                name = project.name
+                description = rootProject.ext.description
+                url = rootProject.ext.url
+                inceptionYear = rootProject.ext.inceptionYear
+                packaging = 'jar'
+                organization {
+                    name = 'xbib'
+                    url = 'https://xbib.org'
+                }
+                developers {
+                    developer {
+                        id = 'jprante'
+                        name = 'Jörg Prante'
+                        email = 'joergprante@gmail.com'
+                        url = 'https://github.com/jprante'
+                    }
+                }
+                scm {
+                    url = rootProject.ext.scmUrl
+                    connection = rootProject.ext.scmConnection
+                    developerConnection = rootProject.ext.scmDeveloperConnection
+                }
+                issueManagement {
+                    system = rootProject.ext.issueManagementSystem
+                    url = rootProject.ext.issueManagementUrl
+                }
+                licenses {
+                    license {
+                        name = rootProject.ext.licenseName
+                        url = rootProject.ext.licenseUrl
+                        distribution = 'repo'
+                    }
+                }
+            }
+        }
+    }
+}
+
+if (project.hasProperty("signing.keyId")) {
+    apply plugin: 'signing'
+    signing {
+        sign publishing.publications.mavenJava
+    }
+}
+
+nexusPublishing {
+    repositories {
+        sonatype {
+            username = project.property('ossrhUsername')
+            password = project.property('ossrhPassword')
+            packageGroup = "org.xbib"
+        }
+    }
+}
diff --git a/gradle/publishing/sonatype.gradle b/gradle/publishing/sonatype.gradle
new file mode 100644
index 0000000..e1813f3
--- /dev/null
+++ b/gradle/publishing/sonatype.gradle
@@ -0,0 +1,11 @@
+
+if (project.hasProperty('ossrhUsername') && project.hasProperty('ossrhPassword')) {
+
+    apply plugin: 'io.codearte.nexus-staging'
+
+    nexusStaging {
+        username = project.property('ossrhUsername')
+        password = project.property('ossrhPassword')
+        packageGroup = "org.xbib"
+    }
+}
diff --git a/gradle/test/junit5.gradle b/gradle/test/junit5.gradle
new file mode 100644
index 0000000..cfef972
--- /dev/null
+++ b/gradle/test/junit5.gradle
@@ -0,0 +1,27 @@
+
+def junitVersion = project.hasProperty('junit.version')?project.property('junit.version'):'5.6.2'
+def hamcrestVersion = project.hasProperty('hamcrest.version')?project.property('hamcrest.version'):'2.2'
+
+dependencies {
+    testImplementation "org.junit.jupiter:junit-jupiter-api:${junitVersion}"
+    testImplementation "org.junit.jupiter:junit-jupiter-params:${junitVersion}"
+    testImplementation "org.hamcrest:hamcrest-library:${hamcrestVersion}"
+    testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:${junitVersion}"
+}
+
+test {
+    useJUnitPlatform()
+    failFast = true
+    testLogging {
+        events 'STARTED', 'PASSED', 'FAILED', 'SKIPPED'
+    }
+    afterSuite { desc, result ->
+        if (!desc.parent) {
+            println "\nTest result: ${result.resultType}"
+            println "Test summary: ${result.testCount} tests, " +
+                    "${result.successfulTestCount} succeeded, " +
+                    "${result.failedTestCount} failed, " +
+                    "${result.skippedTestCount} skipped"
+        }
+    }
+}
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 5c2d1cf..62d4c05 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 80c4ad3..21e622d 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,5 @@
-#Thu Nov 07 15:59:31 CET 2019
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.4.1-all.zip
 zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
index 83f2acf..fbd7c51 100755
--- a/gradlew
+++ b/gradlew
@@ -82,6 +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
@@ -129,6 +130,7 @@ fi
 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
@@ -154,19 +156,19 @@ if [ "$cygwin" = "true" -o "$msys" = "true" ] ; 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
 
@@ -175,14 +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 24467a1..a9f778a 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -29,6 +29,9 @@ 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"
 
@@ -81,6 +84,7 @@ set CMD_LINE_ARGS=%*
 
 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%
 
diff --git a/metrics-api/src/main/java/module-info.java b/metrics-api/src/main/java/module-info.java
new file mode 100644
index 0000000..88e783f
--- /dev/null
+++ b/metrics-api/src/main/java/module-info.java
@@ -0,0 +1,3 @@
+module org.xbib.metrics.api {
+    exports org.xbib.metrics.api;
+}
\ No newline at end of file
diff --git a/metrics-common/build.gradle b/metrics-common/build.gradle
index 740edb1..729b061 100644
--- a/metrics-common/build.gradle
+++ b/metrics-common/build.gradle
@@ -1,3 +1,3 @@
 dependencies {
-    compile project(':metrics-api')
+    api project(':metrics-api')
 }
diff --git a/metrics-common/src/main/java/module-info.java b/metrics-common/src/main/java/module-info.java
new file mode 100644
index 0000000..f417413
--- /dev/null
+++ b/metrics-common/src/main/java/module-info.java
@@ -0,0 +1,4 @@
+module org.xbib.metrics.common {
+    exports org.xbib.metrics.common;
+    requires org.xbib.metrics.api;
+}
diff --git a/metrics-common/src/main/java/org/xbib/metrics/common/CpuTimeClock.java b/metrics-common/src/main/java/org/xbib/metrics/common/CpuTimeClock.java
deleted file mode 100644
index 3dcf61d..0000000
--- a/metrics-common/src/main/java/org/xbib/metrics/common/CpuTimeClock.java
+++ /dev/null
@@ -1,23 +0,0 @@
-package org.xbib.metrics.common;
-
-import org.xbib.metrics.api.Clock;
-
-import java.lang.management.ManagementFactory;
-import java.lang.management.ThreadMXBean;
-
-/**
- * A clock implementation which returns the current thread's CPU time.
- */
-class CpuTimeClock implements Clock {
-    private static final ThreadMXBean THREAD_MX_BEAN = ManagementFactory.getThreadMXBean();
-
-    @Override
-    public long getTick() {
-        return THREAD_MX_BEAN.getCurrentThreadCpuTime();
-    }
-
-    @Override
-    public long getTime() {
-        return System.currentTimeMillis();
-    }
-}
diff --git a/metrics-common/src/main/java/org/xbib/metrics/common/MetricRegistry.java b/metrics-common/src/main/java/org/xbib/metrics/common/MetricRegistry.java
index 20022de..8b9a8b9 100644
--- a/metrics-common/src/main/java/org/xbib/metrics/common/MetricRegistry.java
+++ b/metrics-common/src/main/java/org/xbib/metrics/common/MetricRegistry.java
@@ -5,7 +5,6 @@ import org.xbib.metrics.api.Metric;
 import org.xbib.metrics.api.MetricFilter;
 import org.xbib.metrics.api.MetricName;
 import org.xbib.metrics.api.MetricSet;
-
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
@@ -17,16 +16,12 @@ import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.Executors;
-import java.util.logging.Level;
-import java.util.logging.Logger;
 
 /**
  * A registry of metric instances.
  */
 public class MetricRegistry implements MetricSet {
 
-    private static final Logger logger = Logger.getLogger(MetricRegistry.class.getName());
-
     private final ConcurrentMap<MetricName, Metric> metrics;
 
     private final List<Listener> listeners;
@@ -382,7 +377,6 @@ public class MetricRegistry implements MetricSet {
             try {
                 return register(name, builder.newMetric());
             } catch (IllegalArgumentException e) {
-                logger.log(Level.WARNING, e.getMessage(), e);
                 final Metric added = metrics.get(name);
                 if (builder.isInstance(added)) {
                     return (T) added;