2024-05-07 12:28
Stateful
System
Within a
stateful system, user session information remains stored on the server.
Let me to explain
with an example. Consider an e-commerce website hosted across thr… Read More
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Tutorial on Java, Design Patterns, collections, Struts, jdbc
2024-05-07 10:52
!if,
!else, !elseif, !endif preprocessing constructs are used to define conditional
statements.
conditions.txt@startuml
!$studentMarks = 45
!if ($studentMarks Client : Sorry, bet… Read More
2024-05-07 10:51
Following
Boolean built in functions are supported in PlantUML.
a.
%false()
b.
%true()
c.
%not()
booleanBuiltInFunctions.txt@s… Read More
2024-05-07 10:50
PlantUML
support two types of variables.
a.
Integers
b.
Strings:
Enclosed in either single or double quotes
You can
define a variable using $.!$radius1 = 2… Read More
2024-05-05 19:09
CDN stands
for Content Delivery Network, acts as a service to enhance the speed of content
delivery in applications, making websites respond faster. To illustrate,
consider a scenario where… Read More
2024-05-05 18:59
We can
embed special Unicode characters using below notation.
Syntax
1
XX
Syntax
2
specialUnicodeHandling.txt@startuml
scale 1.5
Client -> Server: Client send fo… Read More
2024-05-05 18:58
OpenIconic
is an open source icon set. As these icons are integrated with creole parser,
you can use them in PlantUML.
How to
see all the available icons?
Command
'listopeniconic'… Read More
2024-05-05 18:55
Symbols |_
used to build a tree.
tree.txt@startuml
scale 1.5
Client -> Server: Client send folder structure
Server -> Client: Server process the folder
note left of Client
root… Read More
2024-05-05 18:53
Using
#color notation, we can apply colors to the table cells.
Example
1: Apply colors to
individual cell
| 1 | Krishna | 34 |
Example
2: Apply colors to
entire row.
| 2… Read More
2024-05-05 14:42
A cache is
a temporary storage, designed to store the result of resource-intensive tasks
and frequently accessed information. By enabling subsequent operations to
retrieve data from the cach… Read More
2024-05-05 14:33
code.txt@startuml
skinparam NoteFontSize 8
scale 1.5
Client -> Server: Client Hello
Server -> Client: Server Hello
note left of Client
public static void main(String args[]){… Read More
2024-05-05 14:30
Using |
separator, we can draw a table.
Example|= id |= name |= age |
| 1 | Krishna | 34 |
| 2 | Ram | 43 |
table.txt
@startuml
skinparam NoteBorderThicknes… Read More
2024-05-04 17:42
Example= Extra Large heading
== Large heading
=== Medium heading
==== Small heading
heading.txt
@startuml
scale 1.5
Client -> Server: Send message
note left o… Read More
2024-05-04 17:41
You can
mix creole and html togther.
mixHtmlCreole.txt@startuml
skinparam NoteFontSize 8
scale 1.5
Client -> Server: Send message
note left of Client
Client is responsible to send… Read More
2024-05-04 17:35
Following
snippets draw horizontal lines.----
====
____
....
horizontalLines.txt
@startuml
skinparam NoteFontSize 8
scale 1.5
Client -> Server: Send messa… Read More
2024-05-04 16:53
Device
fingerprinting
Device
fingerprinting is a method used to identify and track devices based on their
unique characteristics like operating system, screen resol… Read More
2024-05-04 16:43
In this
post, Let's talk about how a single master and multiple slaves architectures
helps to achieve redundancy and high availability to the databases.
Master
Database: The master… Read More
2024-05-03 12:28
Failover
and redundancy are related concepts in computer systems, but they are not
exactly the same.
Redundancy
refers to the presence of duplicate components within a system, whether in… Read More
2024-04-30 05:24
Using
Pandas concat method, we can concatenate the cotent of one ore more data
frames.
Exampledata1 = { 'Name': ['Krishna', 'Chamu', 'Joel'],
'Age': [34, 25, 29],
'City':… Read More
2024-04-30 05:23
Step 1:
Select numeric column
names using ‘select_dtypes’ method.
numeric_column_names
= df.select_dtypes(include=['float64', 'int64']).columns
Step 2:
Extract the nume… Read More
2024-04-30 04:25
In the
world of web development and API design, understanding and designing idempotent
HTTP requests is crucial. In this blog post, we'll delve into what idempotence
means in the context of… Read More
2024-04-26 04:16
Bulleted
lists are represented using *
Example* message 1
* message 2
** submessage1
** submessage
* message 3
* message 4
**
represent sub message.
bulletedList… Read More
2024-04-26 04:16
Using ~
(tilde), we can escape creole characters.
Example
This is
not ~*~*printed in bold~*~*
escapeCreole.txt@startuml
scale 1.5
Client -> Server: Send message
note left… Read More
2024-04-26 04:12
# symbol
create numbered list.
Examplenote left of Client
# message 1
# message 2
## submessage1
## submessage
# message 3
* submessage 1
* submessage 2
# message 4
end note … Read More
2024-04-25 09:11
Java
streams, introduced in Java 8, improvise how the collections of objects are
processed. Streams represent a sequence of elements that can be processed using
operations provided by the St… Read More
2024-04-25 09:10
Java
streams, introduced in Java 8, improvise how the collections of objects are
processed. Streams represent a sequence of elements that can be processed using
operations provided by the St… Read More
2024-04-25 05:46
Using
‘agg’ method of DataFrameGroupBy object, we can apply one or more aggregation
functions on groupby data.
I am using below data set to demonstrate the
examples. Name… Read More
2024-04-25 05:45
We can
iterate over the content of group by data using for loop.
Examplefor group_name, group_data in group_by_object:
print("Group Name:", group_name)
print(group_data)
… Read More
2024-04-25 05:43
Using ‘mean’
method of DataFrameGroupBy object, we can compute the mean of values within
each group.
Exampledata = { 'Name': ['Krishna', 'Chamu', 'Joel', 'Gopi', 'Sravya', "Raj… Read More
2024-04-19 10:49
Following
skinparam commands customize legend font, color.skinparam LegendBackgroundColor palegreen
skinparam LegendBorderColor aqua
skinparam LegendBorderThickness 5
skinparam LegendFontCol… Read More
2024-04-19 10:48
Following
example demonstrate how can we emphasize the text using creole.
emphasizeText.txt@startuml
scale 1.5
skinparam NoteBackgroundColor Wheat
skinparam NoteBorderColor red
skinpara… Read More
2024-04-19 10:46
Following
snippet customize the legend color, font.style>
legend{
FontColor #red
FontName Papyrus
FontSize 24
FontStyle italic
}
style>
legendColo… Read More
2024-04-18 15:37
In the
realm of computer science, searching plays a vital role in various algorithms
and applications. It's the process of finding a specific item within a
collection of items. There are sev… Read More
2024-04-18 06:23
Using
‘sum’ method of DataFrameGroupBy object, we can compute the sum of values
within each group.
Exampledata = { 'Name': ['Krishna', 'Chamu', 'Joel', 'Gopi', 'Sravya', "Raj"]… Read More
2024-04-18 06:23
Using
'DataFrameGroupBy.max()' method, we can get the maximum value for each group.
Exampledata = { 'Age': [34, 25, 29, 41, 52, 23],
'Name': ['Krishna', 'Chamu', 'Joel', 'Gopi', '… Read More
2024-04-18 06:16
Using
'DataFrameGroupBy.max()' method, we can get the maximum value for each group.
Exampledata = { 'Age': [34, 25, 29, 41, 52, 23],
'Name': ['Krishna', 'Chamu', 'Joel', 'Gopi', '… Read More
2024-04-17 09:57
In this
blog post, we'll explore the ins and outs of Java records, a feature introduced
in Java 14 aimed at simplifying the creation of immutable data classes. We'll
cover… Read More
2024-04-17 04:37
captionColorFont.txt@startuml
caption figure 1 : Login Server
Client -> LoginServer: Enter user name
Client -> LoginServer: Enter password
Client -> LoginServer: Submit the form… Read More
2024-04-17 04:34
‘legend’
and ‘end legend’ keywords are used to put a legend to the diagram.
A legend
location can be specified using below keywords combination.
a.
le… Read More
2024-04-17 04:32
Using
‘caption’ keyword, you can add a caption under the diagram.
caption.txt@startuml
caption figure 1 : Login Server
Client -> LoginServer: Enter user name
Client ->… Read More
2024-04-16 06:03
In Spring,
you can create a thread pool using the TaskExecutor interface or its
implementations such as ThreadPoolTaskExecutor. Then, you can submit
asynchronous tasks to this thread pool to… Read More
2024-04-16 04:24
Using DataFrameGroupBy.groups
attribute, we can get a dictionary-like view of the groups formed in groupby operation.
Exampledata = {'Name': ['Krishna', 'Chamu', 'Joel', 'Gopi', 'Sravya'… Read More
2024-04-16 04:24
Using ‘get_group()’
method of DataFrameGroupBy object, we can get a specific group details from the
grouped data based by its group name.
Exampledata = {'Name': ['Krishna', 'Ch… Read More
2024-04-16 04:21
Using ‘last()’
method of DataFrameGroupBy object, we can retrieve the last row from each group
based on the grouping criteria.
Exampledata = {'Name': ['Krishna', 'Chamu', 'Joel… Read More
2024-04-15 14:55
Time is a
fundamental aspect of programming, and in Java, it's essential to understand
the different units of time and how they relate to each other. Whether you're
working with nanoseconds… Read More
2024-04-15 14:50
Following
commands are used to configure title back ground color, border thickness etc.,
skinparam
titleBorderRoundCorner 25
skinparam
titleBorderThickness 3
skinparam
titleBorder… Read More
2024-04-15 14:50
You can
apply creol styles to customzie the diagram title.
creolTitle.txt@startuml
title
# Simple Login Flow example.
----
# Client enter //username and password//, submit to the LoginSer… Read More
2024-04-15 14:48
‘scale’
command is used to zoom the generated image. There are multiple ways to express
the scale.
Example
1: Express scale
factor as a number or fraction.
scale 2.5
scale 3… Read More
2024-04-13 15:57
Using
size() method of DataFrameGroupBy object, we can retrieve the number of
elements in each group. ‘size()’ method returns a Series that contains the
group names as the index… Read More
2024-04-13 15:54
Using ‘first()’
method of DataFrameGroupBy object, we can retrieve the first row from each
group based on the grouping criteria.
Exampledata = {'Name': ['Krishna', 'Cham… Read More
2024-04-13 15:51
Using ‘len’
function, we can get the number of groups in DataFrameGroupBy object.
Examplegroup_by_city = df.groupby('City')
group_by_gender_city = df.groupby(['Gender', 'City'… Read More
2024-04-12 04:10
Using
@startmath/@endmath, we can create standalone AsciiMath formula.
asciiMath.txt@startmath
sum_(i=1)^n i^3=((n(n+1))/2)^2
@endmath
Above
snippet generat… Read More
2024-04-12 04:09
We can
create standalone JLaTeXMath formula using @startlatex/@endlatex.
latexMath.txt@startlatex
\sum_{i=0}^{n-1} (a_i + b_i^2)
@endlatex
Above
snippet generate… Read More
2024-04-12 04:06
Using
styleTag.txt@startyaml
#highlight "name"
#highlight "address" / "city"
#highlight "hobbies" / "1"
#highlight "emails" / "0" / "id"
id: 1
name: Krishna
address:
state: Karnatk… Read More
2024-04-11 15:35
Documentation
is a crucial aspect of coding, providing insights into the purpose and
functionality of various methods and properties. However, maintaining clear and
concise documentation can… Read More
2024-04-11 14:42
Using to_csv()
method, we can To export data from a Pandas DataFrame to a CSV ((Comma-Separated
Values) file.
Example
1: Write dataframe to
csv file
df.to_csv('/Users/Shared/csv/demo1.cs… Read More
2024-04-11 14:41
In this
post and coming subsequent posts, I am going to explain the group by operations
on DataFrame.
What is
Group By operation?
Group By
operation is used to group rows based on one or… Read More
2024-04-11 14:36
Using the
read_csv() method from the Pandas library, we can read the data from an url.
Exampledf = pd.read_csv(url)Find the
below working application.
read_from_url.py
import… Read More
2024-04-10 15:47
In
software development, particularly in Java, there are situations where case
sensitivity in data lookups can be a trouble. Consider scenarios where you need
to retrieve values from a colle… Read More
2024-04-10 15:00
The java.util.ServiceLoader
class in Java provides a simple mechanism for discovering and loading
implementations of a service interface from the classpath. It is part of the
Java Standard L… Read More
2024-04-10 04:05
We can
visualize the yaml document using PlantUML.
helloworld.txt@startyaml
id: 1
name: Krishna
address:
state: Karnatka
city: Bnagalore
country: India
hobbies:
- Playing cri… Read More
2024-04-10 04:04
Using
#highlight directive, we can highlight some parts of the yaml document.
Example#highlight "name" : Highlight name property
#highlight "address" / "city" : Highlight city property i… Read More
2024-04-10 04:01
Using
styleTag.txt@startjson
#highlight "name"
#highlight "address" / "city"
#highlight "hobbies" / "1"
#highlight "emails" / "0" / "id"
{
"id" : 1,
"name" : "Krishna",
"address"… Read More
2024-04-10 03:46
The
Arrays.deepToString() method is a utility method provided in the java.util
package in Java. It's used to generate a string representation of nested
arrays.
When you
pass a multi… Read More
2024-04-09 05:43
A stack is
a fundamental data structure in computer science that follows the Last In,
First Out (LIFO) principle. Imagine a stack of plates where you can only add or… Read More
2024-04-09 03:39
Using
swaplevel() method, we can swap the index levels in a multi index data frame.
Let’s use below data set to demonstrate the
examples. Name Age City Gender Rating… Read More
2024-04-09 03:38
In this
post, I am going to explain how to reshape the dataframe using pivot method.
Signature
DataFrame.pivot(index=None,
columns=None, values=None)’
Following
tabl… Read More
2024-04-09 03:34
In this
post, I am going to explain how to extract the row from a multi index data
frame using ‘loc’ accessor.
Let’s use below data set to experiment with the
examples… Read More
2024-04-08 04:40
In Java,
copying data from an InputStream to an OutputStream is a common task,
especially when dealing with file operations, network communications, or
handling HTTP requests. In this blog p… Read More
2024-04-08 03:45
PlantUML
helps you to visualize the JSON data.
helloworld.txt@startjson
{
"id" : 1,
"name" : "Krishna",
"address" : {
"state" : "Karnatka",
"city" : "Bnagalore",
"country" : "In… Read More
2024-04-08 03:44
Using
#highlight directive, we can highlight some parts of the json document.
Example#highlight "name" : Highlight name property
#highlight "address" / "city" : Highlight city property i… Read More
2024-04-08 03:42
You can
customiae the color, font styles using
styleTag.txt@startuml
skinparam backgroundColor LightBlue
left to right direction
state state1
state state2
state state3
state state… Read More
2024-04-06 06:18
Using get_level_values()
method we can retrieve the values of a specific level from a multi-indexed
DataFrame.
Let’s use
following data set to experiment with the examples. Year… Read More
2024-04-06 06:17
There are
two ways to customize the multi-level index names.
a.
Updating
the index.names property
b.
Using
index.set_names method
Let’s experiment wi… Read More
2024-04-06 06:11
‘df.index.names’
return list of column names involved in a multi index.
Example
multi_index_column_names
= df.index.names
multi_index_column_names.pyimport pandas as… Read More
2024-04-05 15:41
HTTP/2,
commonly pronounced as "http two," marks a notable advancement in the
Hypertext Transfer Protocol (HTTP), the backbone of communication between web
servers a… Read More
2024-04-05 10:53
Spring boot 3 : Hello World rest application Read More
2024-04-05 10:52
In this
post, I am going to explain how to create a hello world rest application using
spring boot3.
Prerequisites
Java17
Maven 3.5
or higher (I tested the app with maven 3.8.4)
… Read More
2024-04-05 09:47
In Java
programming, handling date and time values is a fundamental aspect of many
applications. Whether it's displaying dates in a specific format, parsing user
input, or manipulating tempo… Read More
2024-04-05 05:26
Using
sort_index method, we can sort a multi indexed data frame.
Let’s experiment with the below data set. Year Quarter Sales City
0 2022 1 100 Bangalore
1… Read More
2024-04-05 04:06
In this
post, I am going to explain how to recognize faces using OpenCV built-in face
recognizer.
You can
download this example from below link.
https://github.com/harikrishna553/p… Read More
2024-04-04 11:31
In this
post, I am going to explain how to read videos in OpenCV. Videos in OpenCV are
read frame by frame. Follow below step-by-step procedure to read the video.
Step 1:
Import ope… Read More
2024-04-04 11:31
We can
resize the video by resizing the video frame by frame.
Following snippet resize the frame or image.def resize_frame(frame, scale_width=0.5, scale_height=0.5):
width = int(frame… Read More
2024-03-17 06:09
In this
post, I am going to use Haar Cascade Classifiers, to detect the faces in an
Image. Haar Cascade Classifiers are machine learning models that have been
trained to recognize specific o… Read More
2024-03-12 10:27
One of the
ways to classify databases is by how the data is stored on disk: row- or
column-wise. Tables can be partitioned either horizontally (storing values
belonging to the same row toget… Read More
2024-03-12 06:44
Using #color
notation, we can apply colors to the state diagram.
inlineColor.txt@startuml
left to right direction
state state1 #FF9876
state state2 #lightblue
state state3 #palegreen
st… Read More
2024-03-12 06:44
customizeUsingSkinParam.txt@startuml
skinparam backgroundColor LightBlue
skinparam state {
StartColor PaleGreen
EndColor brown
BackgroundColor gold
BackgroundColor aqua
BackgroundColo… Read More
2024-03-12 06:39
Using
‘note on link’ command, we can put notes on the links.
Example 1state1 --> state2
note on link : This is note 1
Example 2
: multi line note… Read More
2024-03-12 06:29
Durability
in ACID and DBMS means that once you finish a transaction, the changes you made
to the database persist always even if something goes wrong with the compu… Read More
2024-03-10 06:59
SkipList
is a specialized form of a Linked List optimized for rapid search and insertion
operations.
In
SkipLists, both insertion and search tasks are accomplished with a time
compl… Read More
2024-03-09 10:56
Database
systems are classified into two main categories: in-memory and disk-based,
based on how they store and manage data.
In-memory
databases
In-memory… Read More
2024-03-09 08:09
Volatile
Memory
Both
volatile and non-volatile memory are super important in computers. Volatile
memory is like a sticky note - it holds information temporarily and… Read More
2024-02-28 15:18
Using
histogram, we can visualize the distribution on pixel intensities in an image.
Using cv2.calcHist
method, we can compute histogram from an image or specific portion of the
ima… Read More
2024-02-27 04:59
Using
‘str.split()’ method, we can split the text content of a DataFrame column.
I am using following data set to demonstrate the
examples. Name Age City… Read More
2024-02-27 04:58
Multi
indexing is a feature, where we have multi levels of indexing to get better
performance while processing the data.
I am using
below data set to demonstrate the example. Yea… Read More
2024-02-14 09:00
Multi-level
indexing, often referred to as B-tree indexing, is a hierarchical data structure
used in databases for efficiently finding particular records. This approach is
invaluable for ext… Read More
2024-02-14 07:22
Indexing
in databases is like using a book's index to find information quickly. Instead
of searching every page, you just look up a word in the index and go straight
to the page you need.
… Read More
2024-02-13 05:34
Using
histogram, we can visualize the distribution on pixel intensities in an image.
Using cv2.calcHist
method, we can compute histogram from an image or sp… Read More
2024-02-13 05:34
In this
post, I am going to explain how to extract specific portion of the image using
masking technique.
Following
snippet is used to extract the image of intrest using masking tec… Read More
2024-02-13 04:17
Data
governance refers to the system and practices an organization uses to
effectively manage its data. It covers everything from establishing rules and
standards to ensure only author… Read More
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