Java import classes from jar file

Question

I have a Class written which imports some classes from JavaMail. When the application runs, it downloads the file automatically and saves it in a directory called depend. But I can't get it to import the classes from the Javamail jar I downloaded. For Example, I have:

import javax.mail.Message;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

At the top of the file, these classes are located in (Path to program/depend/javax.mail.jar)

Are you using an IDE? If so, did you link the .jar to your buildpath? — Steve P., Dec 01 '13 at 22:25

cmd · Answer 1 · 2013-12-01T22:30:03.127

3

You must ensure that the javamail.jar file is on the classpath.

You can do this using -classpath arg or by setting the CLASSPATH env var.

Here is documentation from Oracle describing java -classpath command line arg
Here is documentation describing how to set CLASSPATH environment var.

edited Dec 01 '13 at 22:30

answered Dec 01 '13 at 22:24

cmd

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How do I do that?, getClass().getResource(filePath) didn't work. – teunw Dec 01 '13 at 22:28
@user3055476 Maybe this question helps: http://stackoverflow.com/questions/252893/how-do-you-change-the-classpath-within-java – PoByBolek Dec 01 '13 at 22:34
1

Your FilePath is about setting the path of some file *your prog* is working with. It won't help Eclipse or JVM. Classpath that you need is about where the classes you want the *JVM* to work with lies. You won't use it in your code, unless you are making plugins. – Gangnus Dec 01 '13 at 22:35

Robin Green · Answer 2 · 2013-12-04T20:08:59.040

0

It sounds like you want to load classes over the network.

This can only be done using a ClassLoader. It cannot be done any other way.

It can be done using RMI - but that uses a ClassLoader internally.

edited Dec 04 '13 at 20:08

answered Dec 01 '13 at 23:47

Robin Green

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Java import classes from jar file

2 Answers2