My main.mk check java and javac version has:
java_version := $(shell java -version 2>&1 | head -n 1 | grep '^java .*[ "]1\.[67][\. "$$]')
and
javac_version := $(shell javac -version 2>&1 | head -n 1 | grep '[ "]1\.[67][\. "$$]')
The regex is not quite right. Since java -version shows:
Picked...