What is a classpath?

Question

What does one mean by setting a classpath and how to do it in Linux (CentOS 5)?

Answer 1

I tried compiling my program... I get the following error...
src]#  /usr/java/jdk1.3.1_04/bin/javac -cp com/ail/cars/app/HeartBeat.java javac: invalid flag: -cp
Usage: javac <options> <source files>
where possible options include:
-g Generate all debugging info
-g:none Generate no debugging info
-encoding <encoding> Specify character encoding used by source files
-target <release> Generate class files for specific VM version
If I just say
src]# /usr/java/jdk1.3.1_04/bin/javac com/ail/cars/app/HeartBeat.java it complies but gives errors, few of them are -->
./com/ail/cars/app/Reader.java:245: cannot resolve symbol
symbol : class Message
location: class com.ail.cars.app.Reader
public void postMessages(Message[] aoMessage)
^
./com/ail/cars/app/Reader.java:258: cannot resolve symbol
symbol : class Message
location: class com.ail.cars.app.Reader
public boolean appendMessage(Message oMessage)
^
./com/ail/cars/app/Reader.java:1417: cannot resolve symbol
symbol : class Transaction
location: class com.ail.cars.app.Reader
private void fillEmployeeDetails(Transaction oTrans, HashMap ohmEmployee)
^