OpenJDK 1.8 which configuaration will take effect, when set /dev/urandom?

Question

we know that there are two options to let SecureRandom to use /dev/urandom instead of /dev/random:

1. change JRE_PATH/lib/security/java.security file
2. set jvm property -Djava.security.egd

but which one take effect when setting both ?

Answer 1

The documentation in <java_dir>/jre/lib/security/java.security clearly says:

The entropy gathering device can also be specified with the System property "java.security.egd". For example:

% java -Djava.security.egd=file:/dev/random MainClass

Specifying this System property will override the "securerandom.source" Security property.

So the system property will always have precedence when set.