Getting Started With SpringBoot Application


Spring Boot is associated open-source Java-based framework wont to produce a small Service. It’s developed by the crucial Team and is employed to create complete and production-ready spring applications. This chapter can offer you an introduction to Spring Boot and familiarizes you with its basic ideas.

What is Spring Boot?
Spring Boot provides a decent platform for Java developers to develop a complete and production-grade spring application that you simply will just run. You’ll start with minimum configurations while not the requirement for a whole Spring configuration setup.

Spring is that the most popular and innovative community for Java developers. They need to modify the method how to build enterprise applications and how to manage them. Spring Boot is their latest innovation to stay up to now with the dynamic technology desires. The first motivation behind developing Spring Boot is to simplify the method for configuring and deploying the spring applications.

Why do we need Spring Boot?

  • Spring Boot is a next-generation attempt to easy spring setup.
  • Spring Boot’s main benefit is configuring the resources based on what it finds in the classpath.
  • If your maven pom includes JPA dependencies and MYSQL driver, then Spring Boot can be created a persistence unit supported by MySQL. If you’ve added an internet dependency, then you may get Spring MVC organized with defaults.
  • When we point out defaults, Spring Boot has its own opinions. If you’re not specifying the main points, it’ll use its own default configurations. If you would like persistence, however, don’t specify anything in your pom file, then Spring Boot configures Hibernate as a JPA supplier with an HSQLDB database.

How does it work?

Some is also asking themselves however will Spring Boot has auto configurations and what will very that basically that actually mean? It really comes right down to three easy Spring Boot annotations that offer this feature:


Between each one of these annotations, Spring Boot is able to provide default project dependencies as well as allow for defaults to be overwritten.

@SpringBootApplication is used within the entry purpose of the application add the category it resides in has to get to the application main technique. The annotation is required and can offer every of the opposite two annotations to your Spring Boot application since the @SpringBootApplication includes each inside.

The @EnableAutoConfiguration does just that it provides each of the representing classes with the Automatic Configuration capability.

Lastly, the @ComponentScan will at initialization scan all the beans and package declarations.

Spring Starter Dependencies
Not solely will Spring Boot include annotations however it conjointly uses Spring Starter Dependencies to make sure that your application starts with the proper dependencies therefore so you can and then you’ll hit the bottom running so to talk.

Many times, as an application grows larger it is laborious to properly set up project dependencies, the Spring Boot Starter plugins can help facilitate dependency management. an example of a spring starter dependency is that the Spring Boot Starter internet dependency.

That will be used so your application can have Rest Endpoints written into your application. Overall, they assist contour the event of those applications so a team can begin from an additional advanced purpose therefore fewer holes are going to be conferred particularly with larger applications.

Spring Boot Features

Web Development
It is a well-suited Spring module for internet application development. we are able to simply produce a self-contained HTTP server using embedded tomcat, Jetty, or Undertow. we are able to use the spring-boot-starter-web module to start out and running applications quickly.

It is a class that provides a convenient way to bootstrap a Spring application which can be started from the main method. You can call start your application just by calling a static run() method.

Application Events and Listeners
Spring Boot uses events to handle a variety of tasks. It allows us to create factories file that is used to add listeners. we can refer to it by using the ApplicationListener key.

Admin Support
Spring Boot provides the facility to modify admin-related features for the appliance. It’s wont to access and manage applications remotely. We will modify it by simply exploiting the spring application admin-enabled property.

Externalized Configuration
Spring Boot permits us to externalize our configuration so we will work with a similar application in several environments. The application uses YAML files to externalize configuration.

Properties Files
Spring Boot provides a rich set of Application Properties. So, we are able to use that within the properties file of our project. The properties file is used to line properties like server-port = 8082 and lots of others. It helps to arrange application properties.

YAML Support
It provides a convenient way for specifying hierarchical configuration. It is a superset of JSON. The SpringApplication class automatically supports YAML. It is a successful alternative to properties.

Type-safe Configuration
A strong type-safe configuration is provided to manipulate and validate the configuration of the application. Application configuration is usually an important task that ought to be type-safe. We are able to conjointly use annotation provided by this library.

Spring Boot uses Common logging for all internal logging. Logging dependencies are managed by default. We must always not modification logging dependencies if there’s no needed customization is required.

Spring Boot applications are spring bases net applications. So, it’s secure by default with basic authentication on all HTTP endpoints. A rich set of Endpoints are obtainable for developing a secure Spring Boot application.

Spring Boot Benefits

  • Application monitoring
  • Auto-Configurable
  • Caching providers
  • Application configurations flexibility

Responsibilities of SpringBoot

Designs, codes or configures, tests, debugs, deploys, documents and maintains web service applications using a variety of software development toolkits, testing/verification applications, and other tools while adhering to specific development best practices and quality standards.

Advantages of Spring Boot

  • It creates stand-alone Spring applications that can be started using Java -jar.
  • It tests web applications easily with the help of different Embedded HTTP servers such as Tomcat, Jetty, etc. We don’t need to deploy WAR files.
  • It provides opinionated ‘starter’ POMs to simplify our Maven configuration.
  • It provides production-ready features such as metrics, health checks, and externalized configuration.
  • There is no requirement for XML configuration.
  • It offers a CLI tool for developing and testing the Spring Boot application.
  • It offers a number of plug-ins.
  • It also minimizes writing multiple boilerplate codes (the code that has to be included in many places with little or no alteration), XML configuration, and annotations.
  • It increases productivity and reduces development time.

The primary roles of Spring-Boot:

  • To provide a bunch of non-functional features/solutions that are very much common to large-scale projects (e.g. embedded servers, security, metrics, health checks, externalized configuration).
  • To provide a radically faster and widely accessible getting started development experience for all Spring development. Since the spring community has evolved so big, it is time to re-invent the way how spring applications are deployed in a much quicker turnaround time.
  • To be get started so quickly using the default values which are supported out of the box in the Spring Boot configurations.

Scope of SpringBoot

Scopes a single bean definition to any range of object instances. Scopes a single bean definition to the lifecycle of one HTTP request; that’s every and each HTTP request can have its own instance of a bean created off the rear of a single bean definition.


I hope this article has provided the basics of Spring Boot Applications. Keep visiting this page for my update on the Spring Boot releases and a list of features in each release. I hope this information provides enough details regarding Spring Boot. This page would be often updated and maintained with the newest information regarding the Spring Boot Application. If you’re searching for any specific information, please write it within the comments section.

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Everything you need to know about Grafana

What is Grafana?

Grafana is multi-platform open-source analytics and interactive visualization internet application. It provides charts, graphs, and alerts for the online once connected to supported knowledge sources.

Why is Grafana important?

Grafana shows groups and corporations what their users very do, not simply what they are saying they are doing. These square measures are called discovered behaviors, and they are extremely telling. Users aren’t terribly adept at predicting their own futures and having analytics permits technical school groups to dig deeper than human-error-prone surveys and watching.

How does Grafana work?

A Grafana dashboard supports multiple panels in a passing single grid, you may visualize results from multiple data sources at an equivalent time. It’s a strong open source analytical and visual image tool that consists of multiple individual panels organized in an exceeding grid.

Benefits of Grafana:

  • Grafana Cloud Traces.
  • Grafana Cloud Metrics.
  • Superfast Prometheus- and Grefait- compatible backend.
  • Grafana Cloud Dashboards. Dedicated Grafana front-end with enhanced reporting, security, management, and more.
  • Grafana Cloud Logs. Based on Grafana Loki, extreme scale, efficiency, and speed.

Where is Grafana used?

Companies use Grafana to observe their infrastructure and log analytics, preponderantly to enhance their operational potency. Dashboards build trailing users and events straightforward as a result of it automates the gathering, management, and viewing of knowledge.

What features does Grafana provide?

The tools that groups really used to uncover insights vary from organization to organization. The following area unit the foremost common (and useful) choices they might expect of data analytics/the visual image tools like Grafana.

Common Grafana features:

  • Visualize: Grafana has a plethora of visualization options to help you understand your data from graphs to histograms, you have it all.
  • Alerts: Grafana lets you define thresholds visually, and get notified via Slack, PagerDuty, and more
  • Unify: You can bring your data together to get better context. Grafana supports dozens of databases, natively.
  • Open-Source: It’s completely open-source. You can use Grafana Cloud, or easily install it on any platform.
  • Explore Logs: Using label filters you can quickly filter and search through the laundry list of logs.
  • Display dashboards: Visualize data with templated or custom reports. Create and share reports.
  • Create and Share reports: Create and share reports with your customers and stakeholders. This feature is not available in the open-source version.

Why do companies use Grafana?

Companies use Grafana to watch their infrastructure and log analytics, preponderantly to boost their operational potency. Dashboards build chase users and events straightforward as a result of it automates the gathering, management, and viewing of knowledge. Product leaders, security analysts, and developers use this knowledge to guide their selections. Studies show that corporations that consider information analytics and mental image tools like the Grafana the area unit are way more profitable than their peers.

Learning Objectives

  • Explore metrics and logs
  • Build dashboards
  • Annotate dashboards
  • Set up alerts

Intended Audience

Centralize the analysis, visualization, and alerting for all of your data with Grafana. Install, administer, and maintain your own instance


Grafana requires a database to store its configuration data, such as users, data sources, and dashboards…

  • MySQL.
  • PostgreSQL
  • SQLite.
  • Supported databases


Grafana permits groups across Stack Overflow to quickly and simply build the custom self-service dashboards for what is vital to them, regardless of wherever the info lives or that info it’s holding on to.

If you want to learn relating to this course, I would suggest you visit

Thank you!

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MySql queries:

Inserting data into a existing table:

Syntax without column names specified:

INSERT INTO table_name VALUES ('value1','value2');


In the example we have inserted the data in a customer_table where we have 4 columns with name cust_id, first_name, last_name, age and we have inserted the data in the columns with this command.

Syntax without column names specified:

INSERT INTO table_name ('column1','column2') VALUES ('value1','value2');


In this example we have inserted the data in three columns excluding the last_name column, by doing this it will store the information in all the columns and will show NULL in the last_name.

Inserting data in multiple rows:

  • To ‘SELECT’ a statement in a table:
Select column_name from table_name;

Following command will show the data stored in the column_name column in the database.

  • To use ‘WHERE’ command in a table:
Select column_name from table_name Where (column_name = condition);

For example:

We have a table with Customers name , age and email given and we need to see only the data of customer whose age is greater than 25.

Select * from customer_table where age>25;

This command will show the data of the customers whose age is greater than 25.

  • To use logical operators in the query:
Select column_name from table_name Where (column_name = condition) AND (column_name = condition) OR (column_name = condition);
  • To update data in the table:
UPDATE table_name SET column_name='abc' WHERE condition(column);

For example to update the last name of a customer:

UPDATE customer_table SET Last_name='John' WHERE cust_id=5

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Creating a Table using MySql queries:

In this we will learn how we can create tables in the database using sql queries. As we know it becomes quite complicated to make the tables manually in the database. To ease the process we can follow the steps to make tables using my sql queries.


CREATE TABLE table_name (
    column1 column1 datatype column1 constraint,
    column2 column2 datatype column2 constraint,
    column3 column3 datatype column3 constraint,


  • NOT NULL CONSTRAINT – Ensures that a column cannot have a null value.
  • DEFAULT CONSTRAINT – Provides a default value for a column when none is specified.
  • UNIQUE CONSTRAINT – Ensures that all value in a column are different.
  • CHECK CONSTRAINT – Make sure all values in a column satisfy certian criteria.
  • PRIMARY_KEY CONSTRAINT – Used to uniquely identify a row in a table.
  • FOREIGN_KEY CONSTRAINT – Used to ensure referential integrity of the data.


  • A primary key is used to uniquely identify each row in a table.
  • A primary key can consists of one or more columns on a table.
  • When multiple columns are used as primary key, it is called as Composite key.
  • A foreign key is a column (or columns) that references a column (most often primary key) of other table.
  • The purpose of foreign key is to referential integrity of the data.

As shown in the above picture, Cust_ID is the foreign key for order table whereas it is primary key for in the Customer table that means the value of Cust_ID will not change in either of the table.

For example we will create a table named as customer_table inside the ‘test’ database:

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MySQL Error 1045 (28000): Access denied for user ‘root’@’localhost’ (using password: YES)

rajeshkumar created the topic: MySQL ERROR 1045 (28000): Access denied for user ‘root’@’localhost’ (using password: YES)

MySQL ERROR 1045 (28000): Access denied for user ‘root’@’localhost’ (using password: YES)

root@server [~]# mysql

ERROR 1045 (28000): Access denied for user ‘root’@’localhost’ (using password: YES)
root@server [~]#

root@server [/var/lib/mysql/mysql]# ls -lhd /var/lib/mysql
drwxr-x–x 179 mysql mysql 12K Aug 25 01:44 /var/lib/mysql/

root@server [/var/lib/mysql/mysql]# chmod 711 /var/lib/mysql/mysql

root@server1 [/var/lib/mysql/mysql]# ls -lhd /var/lib/mysql/mysql
drwx–x–x 2 mysql mysql 4.0K Aug 25 01:32 /var/lib/mysql/mysql/

root@server1 [/var/lib/mysql/mysql]# service mysql restart
Shutting down MySQL.. [ OK ]
Starting MySQL [ OK ]
root@server1 [/var/lib/mysql/mysql]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 1
Server version: 5.0.51a-community MySQL Community Edition (GPL)Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the buffer.

mysql> quit

Rajesh Kumar
Twitt me @

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Creating file system info and put into mysql db

rajeshkumar created the topic: Creating file system info and put into mysql db

Create a perl script for following task…
1. Read the directory mentioned by users and list all the files along with their size and Create a property file which has following info of each file.

# Server name Path File Name date Size
1 rajesh /perforce/server:port/root xyz.txt today 10KB

2. Insert this data into mysql Db in table in same fashion as it is in property file

Rajesh Kumar
Twitt me @

rajeshkumar replied the topic: Re: Creating file system info and put into mysql db

Hi Tushar,

I could make it for reading directory and displaying files in such a given format…

My example program is

$DIR = “/home/rajesh”;

@dirlist = `ls -l $DIR | tr -s ” ” ” “| cut -d ” ” -f5,9`;
foreach (@dirlist)
print “$_ \n”;

Rajesh Kumar
Twitt me @

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SQL Injection: How to check or test for vulnerabilities

SQJ Injection
There are a number of ways of testing an application for vulnerabilities such as SQL Injection. The tests break down into three different methodologies:
Blind Injection:
MySQL example:
If this SQL statement is interpreted by the database then it will take 30 seconds for the page to load.
Error Messages:
If error reporting is enabled and this request is vulnerable to sql injection then the following error will be produced:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘”‘ at line 5
Tautology Based Injection:
http://localhost/test.php?username=’ or 1=1 /*&password=1
In this case supplying a Tautology, or a statement that is always true provides a predictable result. In this case the predictable result would be logging in the attacker with the first user in the database, which is commonly the administrator.
There are tools that automate the use of the methods above to detect SQL Injection in a web application. There are free and open source tools such as Wapiti and Skipfish that do this.
More –
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MySQL Basic Troubleshooting Guide | MySQL common Issues


PLEASE NOTE: I am currently reviewing this Article.

How to check the mysql file location:
> which mysql
> locate mysql

Check mysqld process is started or not?
> service mysqld status
> “mysqld is stopped” – Means mysqld is not running
> “mysqld: unrecognized service” – Means mysqld is not set in service. This can be register using chkconfig under /etc/init.d.
> ps -eaf | grep mysqld

To check if port 3306 is bind with mysqld or another program.
> lsof -i TCP:3306
> netstat -lp | grep 3306
> netstat -tap | grep mysql
> ps -aux | grep mysql
> netstat -a -t – to show only tcp ports

Note: – if you could not found 3306 is listening with mysqld, then it must not be running or running with another ports. To find this, refer my.cnf and pid-file

How to Stop mysqld?
> /etc/init.d/mysqld stop
> kill <pid>
> /sbin/service mysqld start/stop/restart

If you have problems starting the server, here are some things to try:

Check the error log to see why the server does not start.
The Location of error log file can be found in my.cnf or my.ini(windows). please refer below to know more about my.cnf file. The log file can be specified also in mysqld service resided
under /etc/init.d/

Make sure that the server knows where to find the data directory.
Make sure my.cnf file is set with “datadir” and its required ownership and permission. Make sure that the server can access the data directory. The ownership and permissions of the data directory and its contents must be set such that the server can read and modify them.

Verify that the network interfaces the server wants to use are available. If the server starts but you cannot connect to it, you should make sure that you have an entry in /etc/hosts that
looks like this: localhost

If mysqld is running, To find all the variable set using
> mysqladmin -h hostname -p variables

Issues 1:
Can’t start server: Bind on TCP/IP port: Address already in use
Can’t start server: Bind on unix socket…
Use ps to determine whether you have another mysqld server running. If so, shut down the server before starting mysqld again.

Issues 2:
mysqld will not start
Can’t start server: Bind on TCP/IP port: Address already in use
Do you already have another mysqld server running on port: 3306 ?
This may be due to 3306 port is being used or Disk Space issues. You can look up on the log file.

Recovering a crashed MySQL server if the system itself or just the MySQL daemon corrupted table files

You’ll see this when checking the /var/log/syslog, as the MySQL daemon checks tables during its startup.

Apr 17 13:54:44 live1 mysqld[2613]: 090417 13:54:44 [ERROR]
/usr/sbin/mysqld: Table ‘./database1/table1’ is marked as
crashed and should be repaired

In this situation, Database and tables need to be repaired.

> mysql -u root -p
mysql> REPAIR TABLE database1.table1;

This works, but there is a better way: First, using OPTIMIZE in combination with REPAIR is suggested and there is a command line tool only for REPAIR jobs. Consider this call:
> mysqlcheck -u username -p -o –auto-repair -v –optimize database_name

Using “mysqlcheck” is, that it can also be run against all databases in one run
> mysqlcheck -u root -p –auto-repair –check –optimize –all-databases

Recreating databases and tables the right way
mysql> show create database database1;

How to find location of my.cnf (or my.ini on Windows)?

Default options are read from the following files in the given order:

Or, on Windows:
Default options are read from the following files in the given order:
C:\Program Files\MySQL\MySQL Server 5.5\my.ini
C:\Program Files\MySQL\MySQL Server 5.5\my.cnf

This command also help you in linux to find my.conf file location…
> strace mysql “;” 2>&1 | grep cnf

Another Option to use following commands…
> whereis my.cnf
> locate my.cnf
> find – -name my.cnf

my.cnf will contain following…
datadir – The path to the MySQL data directory.
log-error- The location of log file.
pid-file – The path name of the file in which the server should write its process ID.

MySQL Performance Troubleshooting
There are three main utilities I’ll run to in a situation like this:

First I’m going to use top to see if anything is hogging CPU on the machine. If there are non-mysql processes using a substantial percentage of the CPU cores, I’m going to want to havea look at what that is and see about limiting its use or moving it a dedicated server. If I see mysqld using up a lot of CPU, I know it’s working hard and will have to drill into what’shappening inside of MySQL (maybe some poorly written queries). If nothing is apparently chewing up the CPU time, I know that the problem is likely elsewhere.

vmstat 5
I generally run this for at least two or three minutes to get a sense of what the CPU and memory use are like. I’m also watching to see how much time the CPU is stalled waiting for I/Orequests. Doing this for several minutes will make the occasional spikes really stand out and also allow for more time to catch those cron jobs that fire up every few minutes.

iostat -x 5 | grep sdb
I’m going to run it with a short interval (5 or 10 seconds) and do so for several minutes. I’ll likely filter the output so that I only see the output for the most active disk or array (the onewhere all of MySQL’s data lives).

slow queries
To find out about slow queries I’m going hope that the slow query log is enabled and the server has a sane long_query_time. But even the default of 10 seconds is helpful in truly badsituations.

MySQL’s error log
I’ll also want to glance through MySQL’s error log to make sure nothing bad-looking has started to appear. To Find a error log file location, refer my.cnf file “log-error”.

Network issues
telnet your_host_name tcp_ip_port_number.

mysqladmin :
mysqladmin is a client for performing administrative operations. You can use it to check the server’s configuration and current status, to create and drop databases, and more.

mysqladmin -h hostname -p <command_as_follows>

–help, -? – Display a help message and exit.
refresh – Flush all tables and close and open log files.
variables – Display the server system variables and their values.
flush-logs – Flush all logs.
flush-privileges – Reload the grant tables (same as reload).
flush-status – Clear status variables.
password new-password – Set a new password. This changes the password to new-password for the account that you use with mysqladmin for connecting to the server.
ping – Check whether the server is available
processlist – Show a list of active server threads.
shutdown – Stop the server.
status – Display a short server status message.
Uptime – The number of seconds the MySQL server has been running.
Slow queries – The number of queries that have taken more than long_query_time seconds
Open tables – The number of tables that currently are open.


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