It sounds SO SIMPLE but i'm STILL having trouble with this!!

Question

Well after tinkering with Java for three years i thought i was pretty comfortable with it but lo and behold i am completely stuck on the SIMPLEST problem: The good ole classpath. I've always run javac from the dir that has my .java files and never needed to specify the classpath before.
But now for this uni assignment i've got to use servlest, requiring sticking the servlet.jar file in the classpath. I CAN'T DO IT!!
I've tried both setting the CLASSPATH variable in DOS and using the -classpath option in javac, but it just won't recognize it!! My .java files and the servlet.jar file reside in the d:\cse3400 directory.
I've typed at the D:\> prompt:
D:\>SET CLASSPATH=D:\cse3400;D:\cse3400\servlet.jar
then executed javac from the D:\> prompt:
D:\>javac ServletContainer.java
and i get the message
count = 0, total = 52
error: cannot read: ServletContainer.java
count = 0, total = 52
1 error
if i type,
D:\>echo %CLASSPATH%
i get
D:\cse3400;D:\cse3400\servlet.jar
i've also tried just typing:
D:\>javac -classpath d:\cse3400;d:\cse3400\servlet.jar ServletContainer
but i get the same thing.
I've tried the above with only one path mentioned (removing the need for ; seperators) but it still can't find the sourcefile unless i'm in that dir or specify the full path with the filename on javac. I've checked and double checked case sensitve stuff, even renaming the dirs to make sure.
So i really need to get servlet.jar in my classpath somehow, coz otherwise i get the error:
ServletContainer.java:12: cannot resolve symbol
symbol : class ServletConfig
location: package servlet
import javax.servlet.ServletConfig;
I've also tried sticking servlet.jar in the d:\jdk1.3.1\jre\lib\ext directory but that don't work either.
I'm running JDK 1.3.1 for win32 but i've also tried (and failed) with JDK 1.2.2 for win32. I've un-installed them both then just re-installed 1.3.1 incase there was some sort of version conflict or something.
Could someone pleeeeeez help??? I've spent about 6 hours trying to find solutions in zillions of places and all i get is set the CLASSPATH in dos or use -classpath, and IT DOESNT WORK!!!
-Frustrated

Answer 1

It sounds like you're confused between classpath and sourcepath.
The classpath contains class files - compiled Java.
Java source is usually compiled from the directory that contains it (its root package anyway) or by specifying the directory that contains the source. Don't do this by giving the full filename to the source file since this might lead to confusion over the package the code belongs to.
The generated class files then need to be on the classpath for java to run them.
Compare these two lines, one that does the compiling and one that runs:
javac -classpath c:/jars/servlet.jar ServletContainer.java
java -classpath c:/jars/servlet/jar;. ServletContainerNotice that the java command includes the current directory in the classpath since this is where the ServletContainer.class file will be found after compilation. I don't think that it's necessary to include the current directory in the classpath (java used to look there by default) but if you get in the habit of making your classpath explicit every time you'll have fewer problems with it.
If you wanted to get your code compiled somewhere else you'd do something like this:
cd src
javac -classpath c:/jars/servlet.jar -d ../classes ServletContainer.jar
cd ..
java -classpath c:/jars/servlet.jar;classes/ ServletContainerThis then looks in the classes directory for classes too.
Hope this helps.