Exception while executing Java in Jmeter

I am trying to execute Preprocessor written in Java in my Jmeter
performance but I can getting the below exception while doing so I followed
the steps in the following
http://heshans.blogspot.com/2014/03/fixing-javalangclassnotfoundexception.html

I have raised this on Stackoverflow.
http://stackoverflow.com/questions/24273262/exception-while-executing-java-in-jmeter

java.io.FileNotFoundException: ./BSFJava4.class (No such file or directory)

at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(FileInputStream.java:146)
at java.io.FileInputStream.<init>(FileInputStream.java:101)
at org.apache.bsf.util.BSFClassLoader.loadClassData(BSFClassLoader.java:65)
at org.apache.bsf.util.BSFClassLoader.loadClass(BSFClassLoader.java:50)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
at org.apache.bsf.util.EngineUtils.loadClass(EngineUtils.java:372)
at org.apache.bsf.engines.java.JavaEngine.eval(JavaEngine.java:241)
at org.apache.bsf.util.BSFEngineImpl.exec(BSFEngineImpl.java:141)
at org.apache.jmeter.util.BSFTestElement.processFileOrScript(BSFTestElement.java:101)
at org.apache.jmeter.modifiers.BSFPreProcessor.process(BSFPreProcessor.java:41)
at org.apache.jmeter.threads.JMeterThread.runPreProcessors(JMeterThread.java:749)
at org.apache.jmeter.threads.JMeterThread.process_sampler(JMeterThread.java:413)
at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:256)
at java.lang.Thread.run(Thread.java:745)

unable to load class 'BSFJava4':java.lang.ClassNotFoundException:
BSFJava4: java.lang.ClassNotFoundException: BSFJava4
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)

Here is my code

import java.io.BufferedReader;import java.io.File;import
java.io.FileReader;import java.io.IOException;import
java.io.PrintWriter;import java.net.URI;import
java.net.URISyntaxException;import java.util.ArrayList;import
java.util.Arrays;import java.util.HashMap;import
java.util.HashSet;import java.util.List;import java.util.Map;import
java.util.Set;
public class SplitRequestLogs{
public static void main(String[] args){

class Group

String fileName;
List<String> urls = new ArrayList<String>();
Group(String fileName)

this.fileName = fileName;

Map<Set<String>, Group> params = new HashMap<Set<String>, Group>();

params.put(new HashSet<String>(Arrays.asList(new String[] { "lat",
"lng", "radius" })), new Group("6_params_40.csv"));
params.put(new HashSet<String>(Arrays.asList(new String[] { "lat",
"lng", "radius", "page_number", "items_per_page" })), new
Group("5_params_17.csv"));
params.put(new HashSet<String>(Arrays.asList(new String[] { "lat",
"lng", "radius", "page_number", "items_per_page", "eligibility_cc",
"quality_filter" })), new Group("7_params_17.csv"));

try

File dir = new
File("/Users/akushe/POINT_SRC_CODE/places/perftest/jmeter/v3");
File out_dir = new
File("/Users/akushe/POINT_SRC_CODE/places/perftest/jmeter/v3/files");

BufferedReader br = new BufferedReader(new FileReader(new
File(dir, "allRequests.log")));
String s = null;
while ((s = br.readLine()) != null)

URI url = new URI(s);
Set<String> paramVal;
if (url.getQuery() != null & !url.getQuery().isEmpty())

paramVal = new HashSet<String>
(Arrays.asList(url.getQuery().split("")));

else

paramVal = new HashSet<String>(Arrays.asList(url.getPath()));

for (Set<String> paramsSet : params.keySet())

if (paramVal.size() == paramsSet.size())

boolean found = true;

for (String param : paramsSet)

if (!s.contains(param))

found = false;
break;

if (found)

params.get(paramsSet).urls.add(s);
break;

br.close();

for (Group group : params.values())

List<String> urls = group.urls;

PrintWriter pw = new
PrintWriter(out_dir.getCanonicalPath() + "/" + group.fileName);

for (String url : urls)

pw.println(url);

pw.close();

catch (IOException e)

// TODO Auto-generated catch block
e.printStackTrace();

catch (URISyntaxException e)

// TODO Auto-generated catch block
e.printStackTrace();
}}