Run Java with third party JAR

Question

I've been trying for 1 week to run a simple java program using third party jar, but I keep getting error. Just now I try this program as below

import org.apache.commons.lang3.*;
public class HelloWorld{
        public static void main(String[] args){
                String x = "abcd";
                System.out.println(StringUtils.capitalize(x));
        }
}   

and when I try to compile and run, command prompt return error as below

c:\training\java\exercise>javac -cp ".;./org/apache/commons/lang3/commons-lang3-3.9.jar" HelloWorld.java
HelloWorld.java:5: error: cannot find symbol
                System.out.println(StringUtils.capitalize(x));

I take this example from this sites as for reference https://www.programcreek.com/2014/01/compile-and-run-java-in-command-line-with-external-jars/

can anyone help me how to solve this? Thanks in advance enter image description here

Answer 1

There is an article about just that available here

I assume you're on Windows as the working folder has disk C: so it should be Windows.

Bottom line it looks like you're mixing the notions of folder and jar. Make sure that the folder C:\\training\\java\\exercise contains both HelloWorld.java and commons-lang3-3.9.jar

Also make sure you're in the C:\\training\\java\\exercise folder

Then compile like this:

 javac -cp ".;./commons-lang3-3.9.jar" HelloWorld.java 

Now this should create HelloWorld.class file

Now Run the java process:

java  -cp ".;./commons-lang3-3.9.jar" HelloWorld