diff --git a/build.gradle b/build.gradle
index 76782b1b1..67c2a68f7 100644
--- a/build.gradle
+++ b/build.gradle
@@ -251,3 +251,49 @@ subprojects {
     }
   }
 }
+
+task checkDependenciesDotGradle {
+  def buildSrcDepsFile = File.createTempFile('buildSrc', 'deps')
+  buildSrcDepsFile.deleteOnExit()
+  dependsOn createGetBuildSrcDirectDepsTask(buildSrcDepsFile)
+
+  doLast {
+    Set<String> depsInUse = []
+    allprojects {
+      configurations.all {
+        it.dependencies.findAll { it.group != null }.each {
+          // Note: .toString() is required since GString should
+          // not be mixed with Java Strings.
+          depsInUse.add("${it.group}:${it.name}".toString())
+        }
+      }
+    }
+    if (buildSrcDepsFile.exists()) {
+      depsInUse.addAll(buildSrcDepsFile.readLines())
+    }
+    def unusedDeps =
+        rootProject.dependencyMap.keySet()
+            .findAll { !depsInUse.contains(it) }
+            .toSorted()
+
+    if (unusedDeps.isEmpty()) {
+      return
+    }
+    logger.error(
+        "Unused dependencies in dependencies.gradle:\n${unusedDeps.toListString()}")
+    throw new IllegalStateException(
+        "The dependencies.gradle file should only contain direct dependencies.")
+  }
+}
+tasks.build.dependsOn(tasks.checkDependenciesDotGradle)
+
+def createGetBuildSrcDirectDepsTask(outputFileName) {
+  return tasks
+      .create(
+          "getBuildSrcDeps_${java.util.UUID.randomUUID()}".toString(),
+          Exec) {
+    workingDir "${rootDir}/buildSrc"
+    commandLine '../gradlew', 'exportDenpendencies',
+                "-PdependencyExportFile=${outputFileName}"
+  }
+}
diff --git a/buildSrc/build.gradle b/buildSrc/build.gradle
index 98e6b7325..368f34d68 100644
--- a/buildSrc/build.gradle
+++ b/buildSrc/build.gradle
@@ -89,3 +89,21 @@ gradle.projectsEvaluated {
     options.compilerArgs << "-Xlint:unchecked"
   }
 }
+
+task exportDenpendencies {
+  def outputFileProperty = 'dependencyExportFile'
+  def output = project.hasProperty(outputFileProperty)
+      ? new PrintStream(
+          new File(project.getProperty(outputFileProperty)))
+      : System.out
+
+  doLast {
+    project.configurations.all {
+      it.dependencies.findAll {
+        it.group != null
+      }.each {
+        output.println("${it.group}:${it.name}")
+      }
+    }
+  }
+}
diff --git a/dependencies.gradle b/dependencies.gradle
index e90375ae7..6978e69bb 100644
--- a/dependencies.gradle
+++ b/dependencies.gradle
@@ -13,20 +13,17 @@
 // limitations under the License.
 
 ext {
+    // Direct dependencies and compile-time transitive dependencies (i.e.,
+    // those flagged as undeclared-dependency by Nebula-lint).
     dependencyList = [
       'args4j:args4j:2.0.26',
       'com.beust:jcommander:1.60',
       'com.google.api-client:google-api-client:1.29.2',
-      'com.google.api-client:google-api-client-appengine:1.29.2',
-      'com.google.api-client:google-api-client-jackson2:1.20.0',
       'com.google.api-client:google-api-client-java6:1.27.0',
-      'com.google.api-client:google-api-client-servlet:1.29.2',
       'com.google.apis:google-api-services-admin-directory:directory_v1-rev72-1.22.0',
       'com.google.apis:google-api-services-appengine:v1-rev101-1.25.0',
       'com.google.apis:google-api-services-bigquery:v2-rev325-1.22.0',
-      'com.google.apis:google-api-services-clouddebugger:v2-rev8-1.22.0',
       'com.google.apis:google-api-services-cloudkms:v1-rev12-1.22.0',
-      'com.google.apis:google-api-services-cloudresourcemanager:v1-rev6-1.22.0',
       'com.google.apis:google-api-services-dataflow:v1b3-rev196-1.22.0',
       'com.google.apis:google-api-services-dns:v2beta1-rev6-1.22.0',
       'com.google.apis:google-api-services-drive:v2-rev160-1.19.1',
@@ -35,38 +32,27 @@ ext {
       'com.google.apis:google-api-services-sheets:v4-rev483-1.22.0',
       'com.google.apis:google-api-services-storage:v1-rev150-1.22.0',
       'com.google.appengine:appengine-api-1.0-sdk:1.9.48',
-      'com.google.appengine:appengine-api-labs:1.9.48',
       'com.google.appengine:appengine-api-stubs:1.9.48',
       'com.google.appengine:appengine-remote-api:1.9.48',
       'com.google.appengine:appengine-testing:1.9.58',
-      'com.google.appengine:appengine-tools-sdk:1.9.48',
       'com.google.appengine.tools:appengine-gcs-client:0.6',
       'com.google.appengine.tools:appengine-mapreduce:0.9',
       'com.google.appengine.tools:appengine-pipeline:0.2.13',
       'com.google.auth:google-auth-library-credentials:0.16.1',
       'com.google.auth:google-auth-library-oauth2-http:0.16.1',
-      'com.google.auto:auto-common:0.8',
-      'com.google.auto.factory:auto-factory:1.0-beta3',
       'com.google.auto.value:auto-value:1.6.3',
       'com.google.auto.value:auto-value-annotations:1.6.3',
       'com.google.closure-stylesheets:closure-stylesheets:1.5.0',
       'com.google.cloud:google-cloud-core:1.59.0',
       'com.google.cloud:google-cloud-storage:1.59.0',
-      'com.google.cloud.bigdataoss:gcsio:1.4.5',
-      'com.google.cloud.bigdataoss:util:1.4.5',
-      'com.googlecode.charts4j:charts4j:1.3',
       'com.google.code.findbugs:jsr305:3.0.2',
       'com.google.code.gson:gson:2.8.5',
       'com.googlecode.json-simple:json-simple:1.1.1',
       'com.google.dagger:dagger:2.21',
       'com.google.dagger:dagger-compiler:2.21',
-      'com.google.dagger:dagger-producers:2.21',
       'com.google.errorprone:error_prone_annotations:2.3.3',
-      'com.google.errorprone:javac-shaded:9-dev-r4023-3',
       'com.google.flogger:flogger:0.1',
       'com.google.flogger:flogger-system-backend:0.1',
-      'com.google.gdata:core:1.47.1',
-      'com.google.googlejavaformat:google-java-format:1.4',
       'com.google.guava:guava:27.1-jre',
       'com.google.guava:guava-testlib:25.0-jre',
       'com.google.gwt:gwt-user:2.8.2',
@@ -78,27 +64,18 @@ ext {
       'com.google.monitoring-client:metrics:1.0.4',
       'com.google.monitoring-client:stackdriver:1.0.4',
       'com.google.oauth-client:google-oauth-client:1.29.2',
-      'com.google.oauth-client:google-oauth-client-appengine:1.29.2',
       'com.google.oauth-client:google-oauth-client-java6:1.27.0',
       'com.google.oauth-client:google-oauth-client-jetty:1.28.0',
-      'com.google.oauth-client:google-oauth-client-servlet:1.29.2',
-      'com.google.protobuf:protobuf-java:2.6.0',
       'com.google.re2j:re2j:1.1',
       'com.google.template:soy:2018-03-14',
       'com.google.truth.extensions:truth-java8-extension:0.45',
       'com.google.truth:truth:0.45',
       'com.ibm.icu:icu4j:57.1',
       'com.jcraft:jsch:0.1.55',
-      'com.jcraft:jzlib:1.1.3',
-      'commons-codec:commons-codec:1.10',
-      'commons-logging:commons-logging:1.2',
-      'com.squareup:javapoet:1.8.0',
-      'com.squareup:javawriter:2.5.1',
       'com.sun.activation:javax.activation:1.2.0',
       'com.sun.xml.bind:jaxb-impl:2.2.11',
       'com.sun.xml.bind:jaxb-osgi:2.2.11',
       'com.sun.xml.bind:jaxb-xjc:2.2.11',
-      'com.thoughtworks.paranamer:paranamer:2.7',
       'com.thoughtworks.qdox:qdox:1.12.1',
       'dnsjava:dnsjava:2.1.7',
       'io.netty:netty-buffer:4.1.31.Final',
@@ -106,34 +83,27 @@ ext {
       'io.netty:netty-codec-http:4.1.31.Final',
       'io.netty:netty-common:4.1.31.Final',
       'io.netty:netty-handler:4.1.31.Final',
-      'io.netty:netty-resolver:4.1.28.Final',
-      'io.netty:netty-tcnative:2.0.22.Final',
       'io.netty:netty-tcnative-boringssl-static:2.0.22.Final',
       'io.netty:netty-transport:4.1.31.Final',
-      'it.unimi.dsi:fastutil:6.5.16',
       'javax.annotation:jsr250-api:1.0',
       'javax.inject:javax.inject:1',
       'javax.mail:mail:1.4',
       'javax.servlet:servlet-api:2.5',
       'javax.xml.bind:jaxb-api:2.3.0',
-      'javax.xml.soap:javax.xml.soap-api:1.4.0',
       'jline:jline:1.0',
       'joda-time:joda-time:2.9.2',
       'junit:junit:4.12',
       'org.apache.avro:avro:1.8.2',
       'org.apache.beam:beam-runners-direct-java:2.11.0',
       'org.apache.beam:beam-runners-google-cloud-dataflow-java:2.11.0',
-      'org.apache.beam:beam-sdks-common-runner-api:2.2.0',
       'org.apache.beam:beam-sdks-java-core:2.11.0',
       'org.apache.beam:beam-sdks-java-extensions-google-cloud-platform-core:2.11.0',
       'org.apache.beam:beam-sdks-java-io-google-cloud-platform:2.11.0',
-      'org.apache.commons:commons-compress:1.8.1',
       'org.apache.commons:commons-text:1.6',
       'org.apache.ftpserver:ftplet-api:1.0.6',
       'org.apache.ftpserver:ftpserver-core:1.0.6',
       'org.apache.httpcomponents:httpclient:4.5.2',
       'org.apache.httpcomponents:httpcore:4.4.4',
-      'org.apache.mina:mina-core:2.0.4',
       'org.apache.sshd:sshd-core:2.0.0',
       'org.apache.sshd:sshd-scp:2.0.0',
       'org.apache.sshd:sshd-sftp:2.0.0',
@@ -141,26 +111,19 @@ ext {
       'org.bouncycastle:bcpg-jdk15on:1.61',
       'org.bouncycastle:bcpkix-jdk15on:1.61',
       'org.bouncycastle:bcprov-jdk15on:1.61',
-      'org.codehaus.jackson:jackson-core-asl:1.9.13',
-      'org.codehaus.jackson:jackson-mapper-asl:1.9.13',
       'org.glassfish.jaxb:jaxb-runtime:2.3.0',
       'org.hamcrest:hamcrest-all:1.3',
       'org.hamcrest:hamcrest-core:1.3',
       'org.hamcrest:hamcrest-library:1.3',
       'org.joda:joda-money:0.10.0',
       'org.json:json:20160810',
-      'org.khronos:opengl-api:gl1.1-android-2.1_r1',
       'org.mockito:mockito-core:2.25.0',
       'org.mortbay.jetty:jetty:6.1.26',
-      'org.mortbay.jetty:jetty-util:6.1.26',
       'org.seleniumhq.selenium:selenium-api:3.141.59',
       'org.seleniumhq.selenium:selenium-chrome-driver:3.141.59',
       'org.seleniumhq.selenium:selenium-java:3.141.59',
       'org.seleniumhq.selenium:selenium-remote-driver:3.141.59',
-      'org.slf4j:slf4j-api:1.7.16',
       'org.testcontainers:selenium:1.10.7',
-      'org.tukaani:xz:1.8',
-      'org.xerial.snappy:snappy-java:1.1.4-M3',
       'org.yaml:snakeyaml:1.17',
       'xerces:xmlParserAPIs:2.6.2',
       'xpp3:xpp3:1.1.4c'