Speed up maven build times.

maven tips.sh

# rip off from https://zeroturnaround.com/rebellabs/your-maven-build-is-slow-speed-it-up/

# in .bashrc 
set MAVEN_OPTS="-XX:+TieredCompilation -XX:TieredStopAtLevel=1"

# add -DdependencyLocationsEnabled=false to retain fewer outgoing connections.


# compile all modules
mvn -T 1C install -offline

# compile specific module
mvn -T 1C install -pl $moduleName -am -offline 

# -T 1C: one thread per cpu core. -T 4 use 4 threads
# -offline: offline mode, does not check for newer snapshots.
# -pl $moduleName: build only specified module.
# -am: build depended modules (use with -pl).
# PS: mvn clean is not used, helps speedup as it's an incremental build.