# Clone the OpenJDK mercurial repository for JDK8 updates
hg clone http://hg.openjdk.java.net/jdk8u/jdk8u-dev/ jdk8udev

# Enter the directory
cd jdk8udev/

# Make scripts executable
chmod u+x get_source.sh configure

# Fetch the source

# Check for build dependencies and configure a debug build
./configure --enable-debug

# Build it
make clean images

# Enjoy 2 lovely cups of tea (build time around 15 mins on my 8 thread Xeon)

# Your fastdebug JDK can be found in
You're all set now to access extra VM telemetry from a debug VM.