bump base image to x86_64-ubuntu-jdk8u262-b10_openj9-0.21.0 (#112)

diff --git a/core/java8/CHANGELOG.md b/core/java8/CHANGELOG.md
index c9f081f..06bac6d 100644
--- a/core/java8/CHANGELOG.md
+++ b/core/java8/CHANGELOG.md
@@ -21,6 +21,7 @@
 
 ## 1.15.0 (next release)
   - Include latest security fixes with every build.
+  - adoptopenjdk/openjdk8-openj9:x86_64-ubuntu-jdk8u262-b10_openj9-0.21.0
 
 ## 1.14.0
   - Support for __OW_ACTION_VERSION (openwhisk/4761)
diff --git a/core/java8/Dockerfile b/core/java8/Dockerfile
index af6c5ee..2914953 100644
--- a/core/java8/Dockerfile
+++ b/core/java8/Dockerfile
@@ -15,8 +15,8 @@
 # limitations under the License.
 #
 
-# Use AdoptOpenJDK's JDK8, OpenJ9 Critical Patch Update (CPU) release version 0.15.1
-FROM adoptopenjdk/openjdk8-openj9:x86_64-ubuntu-jdk8u222-b10_openj9-0.15.1
+# Use AdoptOpenJDK's JDK8, OpenJ9, ubuntu
+FROM adoptopenjdk/openjdk8-openj9:x86_64-ubuntu-jdk8u262-b10_openj9-0.21.0
 
 RUN rm -rf /var/lib/apt/lists/* \
     && apt-get clean \
diff --git a/core/java8actionloop/CHANGELOG.md b/core/java8actionloop/CHANGELOG.md
index e383e01..f475b0a 100644
--- a/core/java8actionloop/CHANGELOG.md
+++ b/core/java8actionloop/CHANGELOG.md
@@ -21,6 +21,7 @@
 
 ## 1.15.0 (next release)
   - Include latest security fixes with every build.
+  - adoptopenjdk/openjdk8-openj9:x86_64-ubuntu-jdk8u262-b10_openj9-0.21.0
 
 ## 1.14.0
   - Initial release of actionloop-based Java Action
diff --git a/core/java8actionloop/Dockerfile b/core/java8actionloop/Dockerfile
index b461c4d..1003884 100644
--- a/core/java8actionloop/Dockerfile
+++ b/core/java8actionloop/Dockerfile
@@ -28,8 +28,8 @@
   && cd openwhisk-runtime-go-*/main\
   && GO111MODULE=on go build -o /bin/proxy
 
-# Use AdoptOpen JDK8, OpenJ9 release version 0.15.1
-FROM adoptopenjdk/openjdk8-openj9:x86_64-ubuntu-jdk8u222-b10_openj9-0.15.1
+# Use AdoptOpenJDK's JDK8, OpenJ9, ubuntu
+FROM adoptopenjdk/openjdk8-openj9:x86_64-ubuntu-jdk8u262-b10_openj9-0.21.0
 
 # select the builder to use
 ARG GO_PROXY_BUILD_FROM=release