Re: Newbie is puzzled over CLASSPATH

markspace wrote:
 > Redcat wrote:
 >> I have Java EE installed at /usr/local/glassfish3. I've got JAVAHOME set
 >> to /usr/local/glassfish3/jdk7 and CLASSPATH set to /usr/local/glassfish3/
 >> jdk7/lib.
 >
 > This seems wrong. In general those should point to your JDK installation, not
 > glassfish. I see you're using a jdk7 directory, however this feel off as
 > well. I normally separate the container and the JDK into two distinct
 > directory hierarchies.
 >
 > Not saying this could never work, but it seems odd and might have some hidden
 > gotchas.

Libraries belong each in their own directory or JAR.

 >> All was seeming to go smoothly with my Java development until I
 >> installed Apache HTTPComponents. I copied the jar files to /usr/local/
 >> glassfish3/jdk7/lib.
....
 >> I've got a simple HTTPComponents example program that I grabbed off the
 >> web. When I run javac against it I get errors reporting that the
 >> HTTPComponents files can't be found. Another simple Java program that
 >> displays my classpath, and it shows the path I set it to.
 >>
 >> My example program is:
 >> package org.apache.http.examples.client;
 >
 > This seems like a bad idea, declaring your code to be a part of the org.apache
 > package space.

Indeed! And such hubris, too!

 >> import org.apache.http.HttpEntity;
 >>
 >> The error message I get is:
 >> dan@dan-Aspire-4730Z:~/development$ javac ClientAuthentication.java
 >> ClientAuthentication.java:3: error: cannot find symbol
 >> import org.apache.http.HttpEntity;

Because you didn't include the *JAR* in your classpath, but a directory.

 > OK, I think I see. javac doesn't like your class path. The first thing is
 > that you'll need "." mostly likely in the path. The second is that most of us
 > use an IDE or at least ant to do builds, and don't rely on class paths. What
 > happens when you have two or more similar libraries with name collisions?

The OP said they used "blah-blah/lib" in the classpath. That wouldn't work for
JARs; they'd need "blah-blah/lib/*".

--
Lew
Honi soit qui mal y pense.
http://upload.wikimedia.org/wikipedia/commons/c/cf/Friz.jpg