Java Archives - wiki

Create a basic java spring boot application

This is a basic example for beginners for creating a basic java spring boot application using ‘spring-boot-starter-parent’.

In this tutorial I am using Spring tool suite as my IDE.

Step I. Create a Maven project

I.1:  File->New -> Maven Project (You can do it by write clicking in the blank space of Package Explorer )

I.2: I have selected ‘create a simple project ( skip archetye selection)’ this allow me to kip the Archetype selection

I.3 : Setting group id and artifact id and other project related details

Done with the maven project creation, you can see the IDE automatically create the project folder structure like bellow .

You can see the project details in pom.xml file


Add the spring boot dependency

<project xmlns="" xmlns:xsi=""
	<name>My Project</name>
	<description>some description</description>

		<java.version>1.8</java.version> <!-- Setting java version -->
	<parent> <!-- here we are saying our project is a child of the  spring-boot-starter-parent project -->

		<dependency> <!-- Adding spring boot dependency -->

Update the project

write click on project folder->Maven->Update Project

After update we can see JRe updated to 1.8 and added Maven Dependencies


Now we can create our application entry point

Crate a class like bellow (sselect the tic ‘public static void main’ to auto generate the function)

Right click in Package Explorer -> New ->Class

Then add @SpringBootApplication annotation to the class and add, args); inside the main function

package com.mytutor;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

public class MyApp {

	public static void main(String[] args) {
		// TODO Auto-generated method stub, args);


Now we can create our controller 

Right click in Package Explorer -> New ->Class


Add the following code in the file

package com.mytutor.controllers;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

public class MyFirstController {
	@RequestMapping("/home")     //Request mapping https://localhost/home
    String myHome() {
        return "Hello World!";


You are done

Now we can run our application You can press the Green *Play button    Or  you can right click the project folder and select the Run As – >Java Application

Tadaaaaa! Our project is running

Now we can hit the url

We and run Spring boot application from command line also by using the command  mvn spring-boot:run




If you are getting the error “Exception in thread “main” java.lang.NoClassDefFoundError: ch/qos/logback/classic/turbo/TurboFilter ” please add the logback-classic dependency in pom file

		<!-- Exception in thread "main" java.lang.NoClassDefFoundError: ch/qos/logback/classic/turbo/TurboFilter  -->
		<!-- -->



By bm on July 19, 2017 | Java, Spring boot | A comment?
Tags: , ,

String Builder and String Buffer


String objects are immutable ( once created can not be changed ) and it will stored in the  Constant String Pool , so if you chose to do a lot of manipulations with String objects, you will end up with a lot of abandoned String objects in the String pool. To avoiding this memory loss we can use StringBuilder or StringBuffer and can be modified over and over again without causing memory loss

StringBuilder example

StringBuffers are thread-safe, they have synchronized methods to control access so that only one thread can access a StringBuffer object’s synchronized code at a time. Thus, StringBuffer objects are generally safe to use in a multi-threaded environment where multiple threads may be trying to access the same StringBuffer object at the same time.

        String from = "From : ";
        String to = " To : ";

        StringBuilder builder = new StringBuilder();

        Log.i("Result : ", builder.toString());


StringBuffer example

StringBuilder’s access is not synchronized so that it is not thread-safe. The performance of StringBuilder can be better than StringBuffer. Thus, if you are working in a single-threaded environment, using StringBuilder instead of StringBuffer may result in increased performance.

        String from = "From : ";
        String to = " To : ";

        String str = new StringBuffer()

        Log.i("Result : ",str);




By bm on July 26, 2016 | Android, Java | A comment?
Tags: , , ,

Ubuntu set java version

select / set java version

Set java version

sudo update-alternatives --config java

Set javac
sudo update-alternatives --config javac
By bm on April 10, 2014 | Java | A comment?