How to run Jmeter load testing script using java.

JMeter API has an option to run JMeter script which made by Jmeter GUI using java. StandardJMeterEngine is the 'heart' of JMeter. If you must execute a JMeter test from Java code, this is the best option. The absolute minimal code to read the existing .jmx file.
Pre-prerequisites:
1. JMeter install somewhere.
2. Add JMeter jars from /lib and especially /lib/ext folders in your project or module class path.

Build Jmeter load testing script using below steps:
1. Start Jmeter
Click on Jmeter_Home/bin/ApacheJMeter.jar or jmeter.sh to open Jmeter window

2. Add 'Thread Group' under 'Test Plan'
Right-click on the Test Plan > Add > Threads (Users) > Thread Group
Type below values in corresponding field
Number of Threads (users)   : 1
Ramp-Up Period (in seconds) : 1
Loop Count                  : 1

3. Add a Sampler under 'Thread Group'
Right-click on the Thread Group > Add > Sampler > HTTP request
Write below values in corresponding field
Server Name or IP : hiromia.blogspot.com
Port NUmber       : 80
Path              : /

4. Add Listener under 'Thread Group'
Right-click on the Thread Group > Add > Listener > View Results Tree

5. Finally Save Test plan with desired name

Demo Java Code:

 import org.apache.jmeter.engine.StandardJMeterEngine;  
 import org.apache.jmeter.reporters.ResultCollector;  
 import org.apache.jmeter.reporters.Summariser;  
 import org.apache.jmeter.save.SaveService;  
 import org.apache.jmeter.util.JMeterUtils;  
 import org.apache.jorphan.collections.HashTree;  
   
 import java.io.File;  
 import java.io.FileInputStream;  
   
 public class ProgramJmeterJMX {  
   
   public static void main(String[] argv) throws Exception {  
   
     //Set jmeter home for the jmeter utils to load  
     String jmeterHomelocation = "F:\\apache-jmeter-2.13\\";  
     String jmeterPropertieslocation = jmeterHomelocation + "bin\\jmeter.properties";  
   
     // JMeter Engine  
     StandardJMeterEngine jmeter = new StandardJMeterEngine();  
   
   
     // Initialize Properties, logging, locale, etc.  
     JMeterUtils.loadJMeterProperties(new File(jmeterPropertieslocation).getPath());  
     JMeterUtils.setJMeterHome(new File(jmeterHomelocation).getPath());  
     // you can comment this line out to see extra log messages of i.e. DEBUG level  
     JMeterUtils.initLogging();  
     JMeterUtils.initLocale();  
   
     // Initialize JMeter SaveService  
     SaveService.loadProperties();  
   
     // Load existing .jmx Test Plan  
     FileInputStream in = new FileInputStream(new File(jmeterHomelocation + "bin\\webloadtesting.jmx"));  
     HashTree testPlanTree = SaveService.loadTree(in);  
     in.close();  
             
     Summariser summer = null;  
     String summariserName = JMeterUtils.getPropDefault("summariser.name", "summary");  
   
     if (summariserName.length() > 0) {  
       summer = new Summariser(summariserName);  
     }  
   
     ResultCollector logger = new ResultCollector(summer);  
     testPlanTree.add(testPlanTree.getArray()[0], logger);  
   
     // Run JMeter Test  
     jmeter.configure(testPlanTree);  
     jmeter.run();  
   }  
 }     
   

Out put: