read simple json lib file

Question

Today I started learning about json files and I made a test using NetBeans and json-lib :

package tp;

import java.io.FileInputStream;
import java.io.IOException;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import net.sf.json.JSONSerializer;
import org.apache.commons.io.IOUtils;

public class Tp {
    public static void main(String[] args) throws IOException {
        String jsonTxt = IOUtils.toString(new FileInputStream("test/test/test1.json"), "UTF-8");
        System.out.println("jsonTxt.length " + jsonTxt.length());

        JSONArray root = (JSONArray) JSONSerializer.toJSON(jsonTxt);
        JSONObject document = root.getJSONObject(0);

        String tag = document.getString("tag");
        System.out.println("tag " + tag);
    }
}

this is my json file :

{
    "tag": "value"
}

I'm tying to read and display the value but I get :

jsonTxt.length 25    
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/lang/exception/NestableRuntimeException
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:455)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:367)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at tp.Tp.main(Tp.java:15)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.lang.exception.NestableRuntimeException
    at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 13 more
Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)

line 15 is : JSONArray root = (JSONArray) JSONSerializer.toJSON(jsonTxt);

What m'I doing wrong ?

SOLUTION :

adding all the libraries : commons-io-2.4.jar, ezmorph-1.0.6.jar, json-lib-2.4-jdk15.jar, commons-logging-1.2.jar, commons-lang-2.6.jar, commons-beanutils-1.9.2.jar, commons-collections-3.2.1.jar

package tp;

import java.io.FileInputStream;
import java.io.IOException;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import net.sf.json.JSONSerializer;
import org.apache.commons.io.IOUtils;

public class Tp {
    public static void main(String[] args) throws IOException {
        String jsonTxt = IOUtils.toString(new FileInputStream("test/test/test1.json"), "UTF-8");
        System.out.println("jsonTxt.length " + jsonTxt.length());

        JSONObject root = (JSONObject) JSONSerializer.toJSON(jsonTxt);

        String tag = root.getString("tag");
        System.out.println("tag " + tag);
    }
}

Thanks