CODEWITHSUNDEEP
javajarimportclasspath
Bamqf
Bamqf

Reputation: 3542

Java import external jar file

Say I have TryJar.java in ~/jar/

public class TryJar {
    public static void hello() {
        System.out.println("Hello World!");
    }
}

then I type:

javac TryJar.java
jar cf TryJar.jar TryJar.class

I want to import this class in another source file in ~/src/ :

public class TrySrc {
    public static void main(String[] args) {
        TryJar.hello();
    }
}

I tried two ways:

1.

javac -cp ~/jar/TryJar.jar TrySrc.java

it's OK during compilation, but when I try to run it, error occurs:

java -cp .:~/jar/TryJar.jar TrySrc
Exception in thread "main" java.lang.NoClassDefFoundError: TryJar
    at TrySrc.main(TrySrc.java:3)
Caused by: java.lang.ClassNotFoundException: TryJar
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 1 more

2.

I try to include in my .bashrc and .profile the following command(I don't have .bash_profile or .bash_login):

export CLASSPATH=$CLASSPATH:~/jar/TryJar.jar

and:

source .bashrc
source .profile

But this time, it's still wrong:

javac TrySrc.java
TrySrc.java:3: error: cannot find symbol
        TryJar.hello();
        ^
  symbol:   variable TryJar
  location: class TrySrc

What should I do to include the external jar file?

EDIT: The total project contains only two directories:

~/jar/:
   TryJar.java
   TryJar.class
   TryJar.jar
~/src/:
   TrySrc.java

Jar's structure:

jar tf TryJar.jar 
META-INF/
META-INF/MANIFEST.MF
TryJar.class

My system is Ubuntu 12.04, java version:

java version "1.8.0"
Java(TM) SE Runtime Environment (build 1.8.0-b132)
Java HotSpot(TM) 64-Bit Server VM (build 25.0-b70, mixed mode)

Upvotes: 4

Views: 750

Answers (2)

user3374919
user3374919

Reputation: 1

Its failing at compile time. try to import "TryJar" in TrySrc.java first.

Upvotes: 0

Jigar Joshi
Jigar Joshi

Reputation: 240860

in your way 1:

try changing from

java -cp ~/jar/TryJar.jar TrySrc

to

java -cp .:~/jar/TryJar.jar TrySrc

to include current directory in classpath as well to be able to load TrySrc

Upvotes: 2

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