Java SE (Java Platform, Standard Edition)

Hi,

I've just started looking at an application deployed onto a Solaris SPARC machine that is invoked in the following way:

JAVAPATH=/usr/j2sdk1.4/jre/bin/java
CLASSPATH=/usr/jdk1.3/jre/lib/rt.jar
${JAVAPATH} -classpath ${CLASSPATH}

Couple of questions:

1) If the CLASSPATH is passed in using the classpath option, does that mean it overrides any existing environment classpath set?

2) What are the implications of using a 1.4 VM with 1.3 runtime classes??