diff --git a/.travis.yml b/.travis.yml
index 4656aeb..a14008a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,10 @@
 language: java
+
+# Cobertura is not supported in JDK11 so you must downgrade the JDK that Travis uses if you want to use Cobertura with Travis.
+# https://github.com/cobertura/cobertura/issues/381
+jdk:
+  - openjdk8
+
 sudo: false # faster builds
 
 script: "mvn cobertura:cobertura"
diff --git a/README.md b/README.md
index e13f0cb..36f5d15 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,11 @@ Add to your `.travis.yml` file.
 ```yml
 language: java
 
+# Cobertura is not supported in JDK11 so you must downgrade the JDK that Travis uses if you want to use Cobertura with Travis.
+# See https://github.com/cobertura/cobertura/issues/381
+jdk:
+  - openjdk8
+
 script: "mvn cobertura:cobertura"
 
 after_success: