diff --git a/src/functionalTest/java/org.scoverage/ScalaSingleMultiLangModuleTest.java b/src/functionalTest/java/org.scoverage/ScalaSingleMultiLangModuleTest.java
new file mode 100644
index 0000000..3f8dd76
--- /dev/null
+++ b/src/functionalTest/java/org.scoverage/ScalaSingleMultiLangModuleTest.java
@@ -0,0 +1,145 @@
+package org.scoverage;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class ScalaSingleMultiLangModuleTest extends ScoverageFunctionalTest {
+
+    public ScalaSingleMultiLangModuleTest() { super("scala-single-multi-lang-module"); }
+
+    @Test
+    public void test() {
+
+        AssertableBuildResult result = dryRun("clean", "test");
+
+        result.assertTaskDoesntExist(ScoveragePlugin.getCOMPILE_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getREPORT_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getAGGREGATE_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getCHECK_NAME());
+    }
+
+    @Test
+    public void build() {
+
+        AssertableBuildResult result = dryRun("clean", "build");
+
+        result.assertTaskDoesntExist(ScoveragePlugin.getCOMPILE_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getREPORT_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getAGGREGATE_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getCHECK_NAME());
+    }
+
+    @Test
+    public void reportScoverage() {
+
+        AssertableBuildResult result = dryRun("clean", ScoveragePlugin.getREPORT_NAME());
+
+        result.assertTaskExists(ScoveragePlugin.getCOMPILE_NAME());
+        result.assertTaskExists(ScoveragePlugin.getREPORT_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getAGGREGATE_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getCHECK_NAME());
+    }
+
+    @Test
+    public void aggregateScoverage() {
+
+        AssertableBuildResult result = runAndFail("clean", ScoveragePlugin.getAGGREGATE_NAME());
+
+        result.assertNoTasks();
+    }
+
+    @Test
+    public void checkScoverage() throws Exception {
+
+        AssertableBuildResult result = run("clean", ScoveragePlugin.getCHECK_NAME());
+
+        result.assertTaskSucceeded(ScoveragePlugin.getCOMPILE_NAME());
+        result.assertTaskSucceeded(ScoveragePlugin.getREPORT_NAME());
+        result.assertTaskSucceeded(ScoveragePlugin.getCHECK_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getAGGREGATE_NAME());
+
+        assertReportFilesExist();
+        assertCoverage(66.7);
+    }
+
+    @Test
+    public void checkScoverageFails() throws Exception {
+
+        AssertableBuildResult result = runAndFail("clean", ScoveragePlugin.getCHECK_NAME(),
+                "test", "--tests", "org.hello.TestNothingSuite");
+
+        result.assertTaskSucceeded(ScoveragePlugin.getCOMPILE_NAME());
+        result.assertTaskSucceeded(ScoveragePlugin.getREPORT_NAME());
+        result.assertTaskFailed(ScoveragePlugin.getCHECK_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getAGGREGATE_NAME());
+
+        assertReportFilesExist();
+        assertCoverage(0.0);
+    }
+
+    @Test
+    public void reportScoverageWithExcludedClasses() throws Exception {
+
+        AssertableBuildResult result = run("clean", ScoveragePlugin.getREPORT_NAME(),
+                "-PexcludedFile=.*");
+
+        result.assertTaskSucceeded(ScoveragePlugin.getCOMPILE_NAME());
+        result.assertTaskSucceeded(ScoveragePlugin.getREPORT_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getCHECK_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getAGGREGATE_NAME());
+
+        Assert.assertTrue(resolve(reportDir(), "index.html").exists());
+        Assert.assertFalse(resolve(reportDir(), "src/main/scala/org/hello/World.scala.html").exists());
+        assertCoverage(100.0); // coverage is 100 since no classes are covered
+
+        // compiled class should exist in the default classes directory, but not in scoverage
+        Assert.assertTrue(resolve(buildDir(), "classes/scala/main/org/hello/World.class").exists());
+        Assert.assertFalse(resolve(buildDir(), "classes/scala/scoverage/org/hello/World.class").exists());
+    }
+
+    @Test
+    public void reportScoverageWithoutNormalCompilation() throws Exception {
+
+        AssertableBuildResult result = run("clean", ScoveragePlugin.getREPORT_NAME(),
+                "-x", "compileScala");
+
+        result.assertTaskSkipped("compileScala");
+        result.assertTaskSucceeded(ScoveragePlugin.getCOMPILE_NAME());
+        result.assertTaskSucceeded(ScoveragePlugin.getREPORT_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getCHECK_NAME());
+        result.assertTaskDoesntExist(ScoveragePlugin.getAGGREGATE_NAME());
+
+        assertReportFilesExist();
+        assertCoverage(66.7);
+
+        Assert.assertTrue(resolve(reportDir(), "index.html").exists());
+        Assert.assertTrue(resolve(reportDir(), "src/main/scala/org/hello/World.scala.html").exists());
+        Assert.assertFalse(resolve(reportDir(), "src/main/java/org/hello/JavaWorld.java.html").exists());
+
+        Assert.assertTrue(resolve(buildDir(), "classes/java/main/org/hello/JavaWorld.class").exists());
+        Assert.assertTrue(resolve(buildDir(), "classes/java/scoverage/org/hello/JavaWorld.class").exists());
+        Assert.assertTrue(resolve(buildDir(), "classes/scala/main/org/hello/World.class").exists());
+        Assert.assertFalse(resolve(buildDir(), "classes/scala/scoverage/org/hello/World.class").exists());
+    }
+
+    @Test
+    public void reportScoverageWithoutNormalCompilationAndWithExcludedClasses() throws Exception {
+
+        AssertableBuildResult result = run("clean", ScoveragePlugin.getREPORT_NAME(),
+                "-PexcludedFile=.*", "-x", "compileScala");
+
+        Assert.assertTrue(resolve(reportDir(), "index.html").exists());
+        Assert.assertFalse(resolve(reportDir(), "src/main/scala/org/hello/World.scala.html").exists());
+        assertCoverage(100.0); // coverage is 100 since no classes are covered
+
+        // compiled class should exist in the default classes directory, but not in scoverage
+        Assert.assertTrue(resolve(buildDir(), "classes/scala/main/org/hello/World.class").exists());
+        Assert.assertFalse(resolve(buildDir(), "classes/scala/scoverage/org/hello/World.class").exists());
+    }
+
+
+    private void assertReportFilesExist() {
+        Assert.assertTrue(resolve(reportDir(), "index.html").exists());
+        Assert.assertTrue(resolve(reportDir(), "src/main/scala/org/hello/World.scala.html").exists());
+    }
+}
diff --git a/src/functionalTest/resources/projects/scala-single-multi-lang-module/build.gradle b/src/functionalTest/resources/projects/scala-single-multi-lang-module/build.gradle
new file mode 100644
index 0000000..c7ebff2
--- /dev/null
+++ b/src/functionalTest/resources/projects/scala-single-multi-lang-module/build.gradle
@@ -0,0 +1,33 @@
+plugins {
+    id 'org.scoverage'
+}
+
+repositories {
+    jcenter()
+}
+
+description = 'a single-module Scala project with java and scala sources'
+
+apply plugin: 'java'
+apply plugin: 'scala'
+
+dependencies {
+    compile group: 'org.scala-lang', name: 'scala-library', version: "${scalaVersionMajor}.${scalaVersionMinor}.${scalaVersionBuild}"
+
+    testRuntime group: 'org.junit.vintage', name: 'junit-vintage-engine', version: junitVersion
+    testCompile group: 'org.junit.platform', name: 'junit-platform-runner', version: junitPlatformVersion
+
+    testCompile group: 'org.scalatest', name: "scalatest_${scalaVersionMajor}.${scalaVersionMinor}", version: scalatestVersion
+}
+
+test {
+    useJUnitPlatform()
+}
+
+scoverage {
+    minimumRate = 0.3
+}
+
+if (hasProperty("excludedFile")) {
+    scoverage.excludedFiles = [excludedFile]
+}
diff --git a/src/functionalTest/resources/projects/scala-single-multi-lang-module/settings.gradle b/src/functionalTest/resources/projects/scala-single-multi-lang-module/settings.gradle
new file mode 100644
index 0000000..e69de29
diff --git a/src/functionalTest/resources/projects/scala-single-multi-lang-module/src/main/java/org/hello/JavaWorld.java b/src/functionalTest/resources/projects/scala-single-multi-lang-module/src/main/java/org/hello/JavaWorld.java
new file mode 100644
index 0000000..2f199c5
--- /dev/null
+++ b/src/functionalTest/resources/projects/scala-single-multi-lang-module/src/main/java/org/hello/JavaWorld.java
@@ -0,0 +1,7 @@
+package org.hello;
+
+public class JavaWorld {
+    public static void hello() {
+        System.out.println("Hello, World!");
+    }
+}
diff --git a/src/functionalTest/resources/projects/scala-single-multi-lang-module/src/main/scala/org/hello/World.scala b/src/functionalTest/resources/projects/scala-single-multi-lang-module/src/main/scala/org/hello/World.scala
new file mode 100644
index 0000000..b7090dc
--- /dev/null
+++ b/src/functionalTest/resources/projects/scala-single-multi-lang-module/src/main/scala/org/hello/World.scala
@@ -0,0 +1,14 @@
+package org.hello
+
+class World {
+
+  def foo(): String = {
+    val s = "a" + "b"
+    s
+  }
+
+  // not covered by tests
+  def bar(): String = "y"
+
+  def helloFromJava(): Unit = JavaWorld.hello()
+}
diff --git a/src/functionalTest/resources/projects/scala-single-multi-lang-module/src/test/scala/org/hello/TestNothingSuite.scala b/src/functionalTest/resources/projects/scala-single-multi-lang-module/src/test/scala/org/hello/TestNothingSuite.scala
new file mode 100644
index 0000000..b8599be
--- /dev/null
+++ b/src/functionalTest/resources/projects/scala-single-multi-lang-module/src/test/scala/org/hello/TestNothingSuite.scala
@@ -0,0 +1,12 @@
+package org.hello
+
+import org.junit.runner.RunWith
+import org.scalatest.FunSuite
+import org.scalatest.junit.JUnitRunner
+
+@RunWith(classOf[JUnitRunner])
+class TestNothingSuite extends FunSuite {
+
+  test("nothing") {
+  }
+}
diff --git a/src/functionalTest/resources/projects/scala-single-multi-lang-module/src/test/scala/org/hello/WorldSuite.scala b/src/functionalTest/resources/projects/scala-single-multi-lang-module/src/test/scala/org/hello/WorldSuite.scala
new file mode 100644
index 0000000..2e90b74
--- /dev/null
+++ b/src/functionalTest/resources/projects/scala-single-multi-lang-module/src/test/scala/org/hello/WorldSuite.scala
@@ -0,0 +1,17 @@
+package org.hello
+
+import org.junit.runner.RunWith
+import org.scalatest.FunSuite
+import org.scalatest.junit.JUnitRunner
+
+@RunWith(classOf[JUnitRunner])
+class WorldSuite extends FunSuite {
+
+  test("foo") {
+    new World().foo()
+  }
+
+  test("helloFromJava") {
+    new World().helloFromJava()
+  }
+}
diff --git a/src/main/groovy/org/scoverage/ScoveragePlugin.groovy b/src/main/groovy/org/scoverage/ScoveragePlugin.groovy
index 1a4e6c4..af6dc80 100644
--- a/src/main/groovy/org/scoverage/ScoveragePlugin.groovy
+++ b/src/main/groovy/org/scoverage/ScoveragePlugin.groovy
@@ -106,6 +106,7 @@ class ScoveragePlugin implements Plugin<PluginAware> {
         def instrumentedSourceSet = project.sourceSets.create('scoverage') {
 
             resources.source(originalSourceSet.resources)
+            java.source(originalSourceSet.java)
             scala.source(originalSourceSet.scala)
 
             compileClasspath += originalSourceSet.compileClasspath + project.configurations.scoverage