Question

java -Djava.library.path=/usr/local/lib -classpath
/usr/local/share/java/zmq.jar:. hwclient

In the above example why is there “:.” after the classpath?

Answer 1

: The colon is the classpath separator.

. The fullstop is a reference to the current directory

-classpath /usr/local/share/java/zmq.jar:.

Because the classpath overrides the default reference to the current directory the above line adds both /usr/local/share/java/zmq.jar and the current directory to the classpath. Without :. there would be no reference to the current directory and the JVM wouldnt find the hwclient class.