DEV Community: bala d kaveri

🚀 Day 29 of My Automation Journey – Arrays (Full Guide + Tricky Questions)

bala d kaveri — Mon, 06 Apr 2026 18:59:58 +0000

Today’s learning was one of the most important milestones in my journey 🔥

👉 Arrays (core concept)
👉 JVM internal behaviour
👉 Memory understanding
👉 Tricky interview questions
👉 Deep dive into public static void main

This is where coding becomes real engineering 🚀

🔹 PART A – ARRAYS COMPLETE THEORY

🔹 1. What is an Array?

👉 An array is an object

👉 It is a container that:
✔ Stores multiple values
✔ Same data type
✔ Fixed size

🔹 2. What Happens Internally (JVM 🔥)

int[] arr = {10, 20, 30};

👉 Internally JVM converts:

int[] arr = new int[]{10, 20, 30};

💡 JVM:

Creates object in Heap memory
Stores reference in variable

🔹 3. Proof – Array is an Object

System.out.println(arr.getClass());

Output:

class [I

🔹 4. Array Creation

int[] arr1 = {10, 20, 60, 30};
int[] arr2 = new int[5];

🔹 5. Important Points ⚠️

✔ Fixed size
✔ Index starts from 0
✔ Stored in Heap
✔ Default values assigned

🔹 6. Default Values

Type	Default
int	0
boolean	false
object	null

🔹 7. Initialization & Access

arr[0] = 10;
System.out.println(arr[0]);

🔹 8. Looping Through Array

Normal Loop:

for(int i = 0; i < arr.length; i++) {
    System.out.println(arr[i]);
}

Enhanced Loop:

for(int num : arr) {
    System.out.println(num);
}

🔹 9. Multi-Dimensional Array

int[][] matrix = {
    {1, 2},
    {3, 4}
};

🔹 PART B – PROGRAMS

✅ Program 1 – Default Values

int[] arr = new int[3];
System.out.println(arr[0] + " " + arr[1] + " " + arr[2]);

Output:

0 0 0

❌ Program 2 – Index Error

int[] arr = new int[3];
System.out.println(arr[3]);

Output:

ArrayIndexOutOfBoundsException

❌ Program 3 – Length Modification

int[] arr = {1, 2, 3};
System.out.println(arr.length);
arr.length = 10;

Output:

3
Compilation Error

🔥 Program 4 – Reference Behavior

int[] a = {1, 2, 3};
int[] b = a;
b[0] = 100;
System.out.println(a[0]);

Output:

🔥 Program 5 – Comparing Arrays

int[] a = {1, 2, 3};
int[] b = {1, 2, 3};
System.out.println(a == b);

Output:

false

❌ Program 6 – Null Array

int[] arr = null;
System.out.println(arr.length);

Output:

NullPointerException

❌ Program 7 – Negative Size

int[] arr = new int[-5];

Output:

NegativeArraySizeException

🔹 PART C – PRACTICE PROGRAM

package modul4;

import java.util.Scanner;

public class ArrayPractise {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        System.out.println("Enter array Length: ");
        int count = sc.nextInt();

        byte[] by = new byte[count];
        short[] sh = new short[count];

        System.out.println("Byte ");
        for (int i = 0; i < count; i++) {
            System.out.println(by[i]);
        }

        System.out.println("Short ");
        for (int i = 0; i < count; i++) {
            System.out.println(sh[i]);
        }
    }
}

🔍 Output Insight

👉 Prints 0 because of default values

🔹 PART D – MEMORY & ADVANCED CONCEPTS

Separate Memory

int[] a = new int[3];
int[] b = new int[3];

👉 Stored in different memory

Passing Array

void test(int[] arr) {
    arr[0] = 999;
}

👉 Passed by reference

🔹 PART E – TRICKY QUESTIONS

❓ Q1

int[] arr = new int[3];
System.out.println(arr[0] + " " + arr[1] + " " + arr[2]);

✔ Output: 0 0 0
👉 Default values

❓ Q2

System.out.println(arr[3]);

❌ Output: Exception
👉 Index out of range

❓ Q3

arr.length = 10;

❌ Compilation error
👉 Length is final

❓ Q4

int[] b = a;

✔ Same reference

❓ Q5

System.out.println(a == b);

❌ false
👉 Different objects

❓ Q6

int[] arr = null;
System.out.println(arr.length);

❌ NullPointerException

❓ Q7

new int[-5];

❌ NegativeArraySizeException

🔹 PART F – public static void main (DETAILED 🔥)

public static void main(String[] args)

🔍 Deep Breakdown

🔹 public

👉 JVM must access it

🔹 static

👉 No object required

👉 JVM calls directly:

ClassName.main()

🔹 void

👉 No return value

🔹 main

👉 Entry point

🔹 String[] args

👉 Command-line input

java Test hello

👉 args = ["hello"]

💡 Important Insight

👉 Without main() → program won’t run

🔚 FINAL TAKEAWAYS

✔ Array = Object
✔ JVM handles memory
✔ Default values exist
✔ Reference behavior matters
✔ Exceptions are important
✔ main() is entry point

💡 GOLDEN INSIGHT

👉 Arrays are the foundation of all data structures 🚀

Stay tuned 🚀

🤖 A Small Note
I used ChatGPT to help structure and refine this blog while keeping the concepts aligned with my learning.

🚀 Day 28 of My Automation Journey – Nested For Loop

bala d kaveri — Thu, 02 Apr 2026 14:19:05 +0000

Today’s learning was super important 👇

👉 Moving from single loops → nested loops
👉 This is where pattern logic begins 🔥

🔹 1. What is a Nested Loop?

👉 A loop inside another loop is called a nested loop

💡 Structure:

for(row) {
    for(column) {
        // logic
    }
}

🧠 How It Works

👉 Outer loop → controls rows
👉 Inner loop → controls columns

🔹 2. Basic Example (Print 1’s)

for(int row = 1; row <= 2; row++) {
    for(int col = 1; col <= 5; col++) {
        System.out.print(1);
    }
    System.out.println();
}

📤 Output:

11111
11111

🔹 3. Print Row Number

for(int row = 1; row <= 2; row++) {
    for(int col = 1; col <= 5; col++) {
        System.out.print(row);
    }
    System.out.println();
}

📤 Output:

11111
22222

🔹 4. Print Column Number

for(int row = 1; row <= 2; row++) {
    for(int col = 1; col <= 5; col++) {
        System.out.print(col);
    }
    System.out.println();
}

📤 Output:

12345
12345

🔹 5. Rectangle Pattern ⭐

for(int row = 1; row <= 3; row++) {
    for(int col = 1; col <= 5; col++) {
        System.out.print("*");
    }
    System.out.println();
}

📤 Output:

*****
*****
*****

🔹 6. Reverse Triangle Pattern 🔻

int count = 5;

for(int row = 1; row <= 5; row++) {
    for(int col = 1; col <= count; col++) {
        System.out.print("*");
    }
    System.out.println();
    count--;
}

📤 Output:

*****
****
***
**
*

🔹 7. Triangle Pattern 🔺

int count = 1;

for(int row = 1; row <= 5; row++) {
    for(int col = 1; col <= count; col++) {
        System.out.print("*");
    }
    System.out.println();
    count++;
}

📤 Output:

*
**
***
****
*****

🔍 Key Concept (Very Important 🔥)

👉 Inner loop runs completely for each outer loop iteration

Example:

Row 1 → full columns execute
Row 2 → full columns execute again

⚠️ Common Mistake

👉 Forgetting System.out.println();

System.out.print("*"); // stays in same line
System.out.println();  // moves to next line

🔹 Real Understanding Trick 💡

Think like a table:

Row	Columns Execution
1	1 → 5
2	1 → 5

👉 That’s how patterns are built

🔚 Final Takeaways

✔ Nested loop = loop inside loop
✔ Outer loop → rows
✔ Inner loop → columns
✔ Used for pattern problems
✔ Base for advanced logic

💡 Golden Insight

👉 If you understand nested loops, you unlock pattern programming 🔓

🤖 A Small Note
I used ChatGPT to help structure and refine this blog while keeping the concepts aligned with my learning.

🚀 Day 27 of My Automation Journey – Introduction to Selenium & Maven Setup

bala d kaveri — Thu, 02 Apr 2026 13:06:27 +0000

Today marks a big milestone in my automation journey 🎯

Till now, I was learning core Java logic
👉 Today, I stepped into real automation using Selenium

This is where things get exciting 🔥

🔹 1. What is Selenium?

👉 Selenium is a tool used for automating web browsers

That means:

Opening a browser 🌐
Navigating websites
Clicking buttons
Filling forms
Validating UI

💡 In simple terms:

👉 If you can do it manually in a browser, Selenium can automate it.

🔹 2. Why Selenium?

✔ Saves time ⏱
✔ Reduces manual effort
✔ Useful for testing & automation
✔ Industry standard tool

🔹 3. Setting Up Selenium using Maven

Instead of downloading jars manually, we use Maven 📦

👉 Maven helps manage:

Dependencies
Versions
Project structure

🔹 4. Understanding `pom.xml` File

This is the heart of a Maven project ❤️

💻 Sample `pom.xml`:

<project xmlns="http://maven.apache.org/POM/4.0.0">

    <modelVersion>4.0.0</modelVersion>

    <groupId>Selenium1</groupId>
    <artifactId>Selenium1</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.seleniumhq.selenium</groupId>
            <artifactId>selenium-java</artifactId>
            <version>4.18.1</version>
        </dependency>

    </dependencies>

</project>

🔍 Explanation (Important 🔥)

🧠 Project Info:

groupId → Project/company name
artifactId → Project name
version → Current version

⚙️ Properties:

<maven.compiler.source>17</maven.compiler.source>

👉 Defines Java version

📦 Dependencies:

<dependency>

👉 This is where we add external libraries

🔹 5. How to Add Dependency from Maven Repository

👉 Go to: mvnrepository.com

Steps:

Search → selenium-java
Select latest version
Copy dependency
Paste inside <dependencies>

💡 Why this is important?

👉 Instead of manual setup, Maven automatically:

Downloads jars
Manages versions
Handles conflicts

🔹 6. Creating Selenium Setup

Once dependency is added ✅

👉 Maven will download everything automatically

Now we are ready to write our first automation program 🚀

🔹 7. First Selenium Program

package first;

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;

public class First {

    public static void main(String[] args) {

        ChromeDriver driver = new ChromeDriver();
        driver.get("https://google.com");

    }
}

🔍 Logic Explained:

ChromeDriver → launches Chrome browser
driver.get() → opens website

👉 That’s it! Your first automation script 🎉

⚠️ Important Notes:

✔ ChromeDriver should match browser version
✔ Browser will open automatically
✔ Close using driver.quit()

🔹8. 🌐 Browsers Supported by Selenium

Selenium supports multiple browsers using specific drivers 👇

✅ Browser / Driver Mapping

Browser	Driver
Google Chrome	ChromeDriver
Mozilla Firefox	GeckoDriver
Microsoft Edge	EdgeDriver
Safari	SafariDriver
Internet Explorer	IEDriverServer
Opera	OperaDriver
Chromium	ChromeDriver
Brave	ChromeDriver
Vivaldi	ChromeDriver

💡 Key Insight:

👉 Most modern browsers are Chromium-based

👉 So they work using ChromeDriver

🔹9. 💻 Operating Systems Supported by Selenium

Selenium is cross-platform and works across multiple environments 👇

✅ OS / Support Type

Operating System	Support
Windows	Supported
macOS	Supported
Linux	Supported
Unix	Supported

🔧 Extended Environment Support

Environment	Support
Docker	Supported
Jenkins (CI/CD)	Supported
GitHub Actions	Supported
AWS / Azure / GCP	Supported

💡 Key Insight:

👉 Selenium scripts can run on any OS where browser + driver is available

👉 This enables:
✔ Cross-browser testing

✔ Cross-platform automation

✔ Scalable test execution 🚀

🔹 10. Real-World Use Cases

👉 Login automation
👉 Form submissions
👉 Testing UI flows
👉 Web scraping (basic level)

🔚 Final Takeaways

✔ Selenium = Browser Automation
✔ Maven = Dependency Management
✔ pom.xml = Project configuration
✔ Easy setup using Maven repository
✔ First step into real automation 🚀

🤖 A Small Note
I used ChatGPT to help structure and refine this blog while keeping the concepts aligned with my learning.

🚀 Day 26 of My Automation Journey – Conditions, Inputs & Do-While Loop

bala d kaveri — Tue, 31 Mar 2026 13:21:31 +0000

Today’s session was a mix of core Java fundamentals + tricky logic + real-world usage 💡
We explored how conditions work, how loops behave without braces, user input handling, and even touched JSON/XML basics.

Let’s break it down step by step 👇

🔹 1. Condition Must Be Boolean (True/False)

In Java, every condition must return either true or false.

❌ Invalid Example

int i = 1;
while(i) {   // ❌ Compilation Error
    System.out.println(i);
}

👉 Why error?

Java does NOT allow non-boolean conditions
Unlike C/C++, numbers are not treated as true/false

✅ Correct Example

int i = 1;
while(i <= 5) {
    System.out.println(i);
    i++;
}

✔ Condition → i <= 5 → returns boolean
✔ Hence valid

🔹 2. True / False Direct Conditions

You can directly use true or false in conditions.

✅ Example

if(true) {
    System.out.println("Always runs");
}

✔ Output:

Always runs

❌ Example

if(false) {
    System.out.println("Never runs");
}

✔ Output:

(no output)

👉 This is useful for testing or debugging

🔹 3. Removing Curly Braces `{ }`

Java allows skipping { } if only one statement is present.

✅ Example

for(int i = 1; i <= 5; i++)
    System.out.println(i);

✔ Output:

1 2 3 4 5

⚠️ Tricky Case

for(int i = 1; i <= 5; i++)
    System.out.println(i);
    System.out.println("Done");

✔ Output:

1 2 3 4 5
Done

👉 Only the first statement is inside loop
👉 Second statement runs once after loop

🔹 4. Infinite Loop (By Default True)

If condition is always true → loop never stops 😱

Example

for(;;) {
    System.out.println("Infinite Loop");
}

👉 This is equivalent to:

while(true) {
    System.out.println("Infinite Loop");
}

✔ Used in:

Servers
Continuous monitoring systems

🔹 5. break and continue

🔸 break → stops loop completely

for(int i = 1; i <= 5; i++) {
    if(i == 3)
        break;
    System.out.println(i);
}

✔ Output:

1
2

🔸 continue → skips current iteration

for(int i = 1; i <= 5; i++) {
    if(i == 3)
        continue;
    System.out.println(i);
}

✔ Output:

🔹 6. Taking Input from User (Scanner)

To read input in Java, we use Scanner.

Example

import java.util.*;

public class Test {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        System.out.print("Enter your name: ");
        String name = sc.nextLine();

        System.out.println("Hello " + name);
    }
}

⚠️ Important Notes

❌ Java does NOT directly support char input
✔ Workaround:

char ch = sc.next().charAt(0);

✔ For String:

String name = sc.nextLine();

🔹 7. Multiple Inputs Example

Scanner sc = new Scanner(System.in);

System.out.print("Enter Tamil mark: ");
int tamil = sc.nextInt();

System.out.print("Enter English mark: ");
int english = sc.nextInt();

int total = tamil + english;

System.out.println("Total mark: " + total);

✔ Output Example:

Enter Tamil mark: 80
Enter English mark: 90
Total mark: 170

🔹 8. JSON vs XML (Basic Understanding)

🔸 JSON (JavaScript Object Notation)

{
  "username": "Manikandan",
  "password": "1234"
}

✔ Lightweight
✔ Easy to read
✔ Mostly used in APIs

🔸 XML (Extensible Markup Language)

<user>
    <username>Manikandan</username>
    <password>1234</password>
</user>

✔ Structured format
✔ Used in older systems / configs

🔹 9. Do-While Loop

👉 Runs at least once, even if condition is false

Example

int i = 1;

do {
    System.out.println(i);
    i++;
} while(i <= 5);

✔ Output:

1 2 3 4 5

🔥 Key Difference

Loop Type	Condition Check
while	Before execution
do-while	After execution

🧠 Key Takeaways

✔ Condition must always be boolean
✔ Java does NOT allow non-boolean conditions
✔ Without {}, only one statement is considered
✔ Infinite loops happen when condition is always true
✔ break → exits loop
✔ continue → skips iteration
✔ Scanner is used for user input
✔ JSON is lightweight, XML is structured
✔ do-while runs at least once

🏁 Conclusion

Today was all about understanding how Java actually behaves under the hood 🧠

These small concepts are very important when:

Writing automation scripts
Handling test data
Building logic-driven frameworks

🔥 Step by step, building strong fundamentals in automation!

🤖 A Small Note
I used ChatGPT to help structure and refine this blog while keeping the concepts aligned with my learning.

🚀 Day 25 of My Automation Journey – Deep Dive into Logic (Part 2)

bala d kaveri — Mon, 30 Mar 2026 12:40:28 +0000

Continuing from earlier, here are the remaining core number programs with full step-by-step explanations to strengthen logic building 👇

🔹 6. Divisors of a Number – Correct Logic

💻 Program:

int user = 15;

for(int i = 1; i <= user; i++) {
    if(user % i == 0)
        System.out.println(i);
}

🧠 Logic Explained:

user % i == 0 means:
👉 “Can i divide user without remainder?”
Loop runs from 1 → 15

🔍 Step-by-Step Trace:

i	15 % i	Result
1	0	✅ Print
2	1	❌
3	0	✅
4	3	❌
5	0	✅
15	0	✅

📤 Output:

1 3 5 15

💡 Key Insight:

👉 Divisors are numbers that perfectly divide the given number

🔹 7. Count of Divisors

💻 Program:

int user = 15;
int count = 0;

for(int i = 1; i <= user; i++) {
    if(user % i == 0)
        count++;
}

System.out.println(count);

🧠 Logic Explained:

Same logic as divisors
Instead of printing → we count

🔍 Example:

Divisors of 15 → 1, 3, 5, 15

👉 Count = 4

📤 Output:

💡 Key Insight:

👉 Reuse logic + add counter → powerful pattern

🔹 8. Count of Digits

💻 Program:

int user = 12345;
int count = 0;

while(user > 0) {
    user = user / 10;
    count++;
}

System.out.println(count);

🧠 Logic Explained:

Each division by 10 removes one digit

🔍 Step-by-Step:

Step	user	count
1	12345 → 1234	1
2	1234 → 123	2
3	123 → 12	3
4	12 → 1	4
5	1 → 0	5

📤 Output:

💡 Key Insight:

👉 Number of times you divide = number of digits

🔹 9. Sum of Digits

💻 Program:

int user = 123;
int sum = 0;

while(user > 0) {
    int digit = user % 10;
    sum = sum + digit;
    user = user / 10;
}

System.out.println(sum);

🧠 Logic Explained:

We do 3 operations:

Extract last digit → % 10
Add to sum
Remove digit → / 10

🔍 Step-by-Step:

Step	digit	sum	user
1	3	3	12
2	2	5	1
3	1	6	0

📤 Output:

💡 Key Insight:

👉 % 10 and / 10 are the backbone of number problems

🔹 10. Palindrome Number

💻 Program:

int user = 121;
int original = user;
int reverse = 0;

while(user > 0) {
    int digit = user % 10;
    reverse = reverse * 10 + digit;
    user = user / 10;
}

if(original == reverse)
    System.out.println("Palindrome");
else
    System.out.println("Not Palindrome");

🧠 Logic Explained:

👉 A palindrome reads the same forward and backward

🔍 Step-by-Step:

Step	digit	reverse	user
1	1	1	12
2	2	12	1
3	1	121	0

📤 Output:

Palindrome

❌ Non-Palindrome Example:

123 → reverse = 321 → Not equal

💡 Key Formula:

reverse = reverse * 10 + digit

🔚 Final Takeaways

✔ Divisors → user % i == 0
✔ Count → reuse + increment
✔ Digits → / 10 removes digits
✔ Sum → % 10 extracts digits
✔ Palindrome → reverse + compare

💡 Golden Rule

👉 Almost ALL number-based problems depend on:

% 10  → Extract last digit
/ 10  → Remove last digit

Master this → you unlock most logic problems 🚀

🔥 Consistency + tracing logic = strong programming foundation!

🤖 A Small Note
I used ChatGPT to help structure and refine this blog while keeping the concepts aligned with my learning.

🚀 Day 25 of My Automation Journey – Prime Numbers, Reverse Logic & Loops

bala d kaveri — Mon, 30 Mar 2026 12:12:16 +0000

Today, instead of just writing programs, I focused on understanding the “WHY” behind each logic. Let’s break everything down step by step 👇

🔹 1. Divisors Logic – Step-by-Step Understanding

💻 Program:

int user = 15;
int i = 0;

while (i <= user) {
    if (i % user == 0)
        System.out.println(i);
    i++;
}

🧠 Logic Explained:

i % user == 0 means:
👉 “Is i divisible by user?”
Loop runs from 0 → 15

Let’s trace:

i value	i % 15	Condition
0	0	✅ Print
1–14	Not 0	❌ Skip
15	0	✅ Print

📤 Output:

0
15

⚠️ Important Insight:

👉 This program is actually finding multiples of 15 within range, NOT divisors.

✅ Correct Divisor Logic should be:

if (user % i == 0)

🔹 2. Prime Number Logic – Deep Explanation

💻 Program:

int user = 3;
boolean status = true;
int i = 2;

while(i < user) {
    if(user % i == 0) {
        status = false;
        break;
    }
    i++;
}

if (status==true)
    System.out.println("Prime");
else
    System.out.println("Not a prime");

🧠 What is a Prime Number?

A number is prime if:

It has exactly 2 factors → 1 and itself

🔍 Step-by-Step Flow:

Start checking from i = 2
Why?
👉 Because:
- Dividing by 1 is always true
- Dividing by itself is always true So we skip both

🧪 Example: user = 3

i	Condition (3 % i)	Result
2	3 % 2 ≠ 0	Continue

Loop ends → No divisor found → Prime ✅

💡 Why `boolean status`?

Acts like a flag
Initially assume → true (prime)
If any divisor found → false

⚡ Why `break`?

As soon as one divisor is found: 👉 No need to continue checking 👉 Improves performance 🚀

🔹 3. Reverse Number Logic – Deep Breakdown

💻 Program:

int user = 123;
int reverse = 0;

while(user > 0) {
    int digit = user % 10;
    reverse = reverse * 10 + digit;
    user = user / 10;
}

System.out.println(reverse);

🧠 Core Idea:

We:

Extract last digit
Append it to reverse
Remove last digit

🔍 Step-by-Step Execution:

Step	user	digit	reverse calculation	reverse
1	123	3	0*10 + 3	3
2	12	2	3*10 + 2	32
3	1	1	32*10 + 1	321

📤 Output:

💡 Key Formula:

reverse = reverse * 10 + digit

👉 This shifts digits left and adds new digit

🔹 4. While Loop vs For Loop – Conceptual Clarity

🔁 While Loop

int i = 0;
while(i <= 10) {
    System.out.println(i);
    i++;
}

🧠 Logic:

Initialization → outside
Condition → inside while
Increment → manual

👉 Used when:

Iterations are unknown
Condition-based looping

🔁 For Loop

for(int i = 0; i <= 10; i++) {
    System.out.println(i);
}

🧠 Logic:

Everything in one line:
- init, condition, increment

👉 Used when:

Iterations are known

📤 Output (Both):

0 1 2 3 4 5 6 7 8 9 10

🔹 5. Bonus Insight 💡

🖥️ Ctrl + Shift + I

Auto formats code
Improves readability
Saves time in debugging

🔚 Final Takeaways

✔ % operator is key for divisibility logic
✔ Prime = no divisors between 2 and n-1
✔ Boolean is best for true/false conditions
✔ Reverse logic = extract + rebuild
✔ Loops = backbone of logic building

🔥 The more you trace step-by-step, the stronger your logic becomes!

🤖 A Small Note
I used ChatGPT to help structure and refine this blog while keeping the concepts aligned with my learning.

🚀 Day 24 of My Automation Journey – Looping Statements (While Loop)

bala d kaveri — Fri, 27 Mar 2026 12:31:07 +0000

Today I explored Looping Statements in Java, especially the while loop.

Loops are very important because they help us repeat a task multiple times without writing duplicate code.

🔹 What is a Loop?

👉 A loop is used to execute a block of code repeatedly based on a condition.

🔁 Types of Loops in Java

✔ While Loop
✔ For Loop
✔ Do-While Loop

👉 Today focus: While Loop

🔹 While Loop Syntax

while(condition) {
    // code
}

✔ Condition is checked first
✔ If true → executes
✔ If false → stops

🔍 Scenario 1: Print same number multiple times
❓ Question

Print 1 five times

int i = 1;

while(i <= 5) {
    System.out.print(1 + " ");
    i++;
}

📤 Output

1 1 1 1 1

✅ Explanation

✔ Loop runs 5 times
✔ Always prints 1

🔍 Scenario 2: Print numbers from 1 to 5
❓ Question

Print numbers from 1 to 5

int i = 1;

while(i <= 5) {
    System.out.print(i + " ");
    i++;
}

📤 Output

1 2 3 4 5

✅ Explanation

✔ i increases each time
✔ Prints updated value

🔍 Scenario 3: Print odd numbers
❓ Question

Print odd numbers from 1 to 10

int i = 1;

while(i <= 10) {
    if(i % 2 != 0) {
        System.out.print(i + " ");
    }
    i++;
}

📤 Output

1 3 5 7 9

✅ Explanation

✔ i % 2 != 0 → odd numbers
✔ Even numbers skipped

🔍 Scenario 4: Multiplication Table (×5)
❓ Question

Print multiplication table of 5

int i = 1;

while(i <= 5) {
    System.out.println(i + " * 5 = " + i * 5);
    i++;
}

📤 Output

✅ Explanation

✔ Loop runs 5 times
✔ Multiplies i * 5

🔍 Scenario 5: Multiples of 3 AND 5
❓ Question

Print numbers divisible by both 3 and 5

int i = 1;

while (i <= 30) {
    if (i % 3 == 0 && i % 5 == 0)
        System.out.println(i);
    i++;
}

📤 Output

15
30

✅ Explanation

✔ && → both conditions must be true
✔ Only multiples of 15 printed

🔍 Scenario 6: Multiples of 3 OR 5
❓ Question

Print numbers divisible by 3 OR 5

int i = 1;

while (i <= 10) {
    if (i % 3 == 0 || i % 5 == 0)
        System.out.println(i);
    i++;
}

📤 Output

✅ Explanation

✔ || → any one condition true
✔ More numbers printed

🔍 Scenario 7: Multiple Conditions with if-else
❓ Question

Print different messages based on divisibility

int i = 1;

while (i <= 20) {

    if (i % 3 == 0 && i % 5 == 0)
        System.out.println(i + " multiply by both");

    else if (i % 3 == 0)
        System.out.println(i + " multiply by 3");

    else if (i % 5 == 0)
        System.out.println(i + " multiply by 5");

    else
        System.out.println(i);

    i++;
}

📤 Output (Sample)

8
9 multiply by 3
10 multiply by 5
11
12 multiply by 3
13
14
15 multiply by both
16
17
18 multiply by 3

✅ Explanation

✔ Priority matters
✔ First matching condition executes

⚠️ Common Mistakes

❌ Forgetting i++ → Infinite loop 😱
❌ Wrong condition → loop never runs
❌ Using = instead of ==

🧠 Key Takeaways

✔ While loop checks condition first
✔ Used when number of iterations is unknown
✔ i++ is very important
✔ && → both conditions
✔ || → any one condition
✔ Can combine with if-else for complex logic

🏁 Conclusion

Today I learned how to use while loop effectively with conditions.

This is very useful in automation for:

✔ Repeating test steps
✔ Data-driven testing
✔ Iterating through elements

Step by step, I’m improving my Java logic for Selenium Automation 🚀

🤖 A Small Note

I used ChatGPT to help structure and refine this blog while ensuring the concepts remain aligned with my trainer’s explanations.

🚀 Day 23 of My Automation Journey – Switch Case Tricky Questions

bala d kaveri — Wed, 25 Mar 2026 07:15:40 +0000

Today I explored advanced and tricky scenarios in Java Switch Case.

At first glance, switch-case looks simple… but when you remove break, use default, or mix data types — things get very tricky 😲

This is also a favorite topic in interviews.

🔹 Before Java 8 – Traditional Switch

int x = 2;

switch(x) {
    case 1:
        System.out.println("One");
        break;
    case 2:
        System.out.println("Two");
        break;
    case 3:
        System.out.println("Three");
        break;
    default:
        System.out.println("Default");
}

📤 Output

Two

✔ break stops execution
✔ Only matching case executes

🔹 After Java 8+ (Arrow Syntax)

int x = 2;

switch(x) {
    case 1 -> System.out.println("Hi");
    case 2 -> System.out.println("Welcome");
    default -> System.out.println("Hello");
}

📤 Output

Welcome

✔ No need for break
✔ No fall-through

🔹 Switch Expression (Java 12+)

int x = 2;

int result = switch(x) {
    case 1 -> 10;
    case 2 -> 20;
    default -> 0;
};

System.out.println(result);

📤 Output

🔹 Java 17+ Pattern Matching

Object obj = "Hello";

switch(obj) {
    case String s -> System.out.println(s.length());
    case Integer i -> System.out.println(i * 2);
    default -> System.out.println("Other");
}

📤 Output

🔥 Tricky Questions
🔍 1. Missing break (Fall-through)

int x = 2;

switch(x) {
    case 1:
        System.out.println("One");
    case 2:
        System.out.println("Two");
    case 3:
        System.out.println("Three");
    default:
        System.out.println("Default");
}

📤 Output

Two
Three

Default
✅ Explanation

✔ Starts from matching case → case 2
✔ No break → continues executing all below

🔍 2. char vs ASCII

char ch = 'A';

switch(ch) {
    case 65:
        System.out.println("ASCII 65");
        break;
    case 'A':
        System.out.println("Character A");
}

📤 Output

ASCII 65

✅ Explanation

✔ 'A' = 65 internally
✔ First matching case executes

🔍 3. Expression inside switch

int x = 10;

switch(x / 2) {
    case 5:
        System.out.println("Five");
        break;
    case 10:
        System.out.println("Ten");
}

📤 Output

Five

✅ Explanation

✔ x/2 = 5 → matches case 5

🔍 4. Multiple case labels

int x = 2;

switch(x) {
    case 1:
    case 2:
        System.out.println("One or Two");
        break;
    case 3:
        System.out.println("Three");
}

📤 Output

One or Two

✅ Explanation

✔ Multiple cases share same block

🔍 5. Missing break again

int x = 2;

switch(x) {
    case 1:
    case 2:
        System.out.println("One or Two");
    case 3:
        System.out.println("Three");
}

📤 Output

One or Two
Three

✅ Explanation

✔ Fall-through again due to missing break

🔍 6. Fall-through chain

int x = 3;

switch(x) {
    case 1:
        System.out.println("One");
        break;
    case 2:
        System.out.println("Two");
    case 3:
        System.out.println("Three");
    case 4:
        System.out.println("Four");
        break;
}

📤 Output

Three
Four

✅ Explanation

✔ Starts at case 3
✔ No break → continues

🔍 7. Default in middle

int x = 2;

switch(x) {
    default:
        System.out.println("Default");
    case 1:
        System.out.println("One");
        break;
    case 2:
        System.out.println("Two");
}

📤 Output

Two

✅ Explanation

✔ Matching case runs directly
✔ Default is ignored

🔍 8. Default fall-through

int x = 5;

switch(x) {
    case 1:
        System.out.println("One");
    default:
        System.out.println("Default");
    case 5:
        System.out.println("Five");
}

📤 Output

Default
Five

✅ Explanation

✔ No match → default executes
✔ Then continues to case 5

🔍 9. final variable in case

final int a = 1;
int b = 2;

switch(b) {
    case a:
        System.out.println("A");
        break;
    case a + 1:
        System.out.println("A+1");
}

📤 Output

A+1

✅ Explanation

✔ final makes it constant → allowed in case

🔍 10. String fall-through

String s = "Java";

switch(s) {
    case "Java":
        System.out.println("Java");
    case "JAVA":
        System.out.println("JAVA");
        break;
}

📤 Output

Java
JAVA

✅ Explanation

✔ Missing break → fall-through

🔍 11. null in switch

String s = null;

switch(s) {
    case "Hi":
        System.out.println("Hi");
        break;
    default:
        System.out.println("Default");
}

📤 Result

NullPointerException

✅ Explanation

✔ switch does NOT accept null

🔍 12. Duplicate case

int x = 1;

switch(x) {
    case 1:
        System.out.println("One");
        break;
    case 1:
        System.out.println("Duplicate");
}

📤 Result

Compile Time Error

✅ Explanation

✔ Duplicate case not allowed

🔍 13. Duplicate constant

final int a = 2;

switch(2) {
    case a:
        System.out.println("A");
        break;
    case 2:
        System.out.println("Two");
}

📤 Result

Compile Time Error

✅ Explanation

✔ Both represent same value → duplicate

🔍 14. Nested switch

int x = 1;

switch(x) {
    case 1:
        switch(x + 1) {
            case 2:
                System.out.println("Inner Two");
        }
    case 2:
        System.out.println("Outer Two");
}

📤 Output

Inner Two
Outer Two

✅ Explanation

✔ Inner switch executes
✔ No break → outer continues

🧠 Key Takeaways

✔ Missing break = fall-through
✔ default can be anywhere
✔ final variables allowed in case
✔ Duplicate case = compile error
✔ null not allowed
✔ Arrow syntax avoids fall-through

🏁 Conclusion

Today I learned how small mistakes in switch-case can lead to unexpected outputs.

These tricky questions are extremely helpful for:

✔ Java interviews
✔ Debugging code
✔ Writing clean logic in automation

Step by step, I’m strengthening my Java fundamentals for Selenium Automation 🚀

🤖 A Small Note

I used ChatGPT to help structure and refine this blog while ensuring the concepts remain aligned with my trainer’s explanations.

🚀 Day 22 of My Automation Journey – Switch Case Statement in Java

bala d kaveri — Wed, 25 Mar 2026 06:53:40 +0000

Today I learned about another important decision-making concept in Java 👉 Switch Case Statement.

It is very useful when we need to compare one value against multiple options.

🔹 What is Switch Case?

A switch statement allows us to select one block of code from multiple choices.

👉 Instead of writing multiple if-else, we can use switch for better readability.

🧠 Syntax

switch(expression) {

    case value1:
        // code
        break;

    case value2:
        // code
        break;

    default:
        // default code
}

🔑 Important Points

✔ switch works with:

int char String enum

❌ Not supported: float, double, boolean

🔸 What is break?

👉 break is used to stop execution of switch

Without break, Java will continue executing next cases (fall-through) ⚠️

🔸 What is continue?

👉 continue is NOT used inside switch directly

✔ It is used inside loops
✔ But can be used in switch only if switch is inside a loop

🔸 Switch Without Braces ❗

switch(day)
    case 1:
        System.out.println("Monday");

❌ This is INVALID in Java

👉 Curly braces {} are mandatory

💡 Scenario-Based Programs
🍽️ Scenario 1: Restaurant Menu Selection

`❓ Question

Select food using number:

1 → Idli
2 → Dosa
3 → Pongal
4 → Poori
`

private void scenario1() {

    int item = 3;

    switch (item) {

    case 1:
        System.out.println("Idli");
        break;

    case 2:
        System.out.println("Dosa");
        break;

    case 3:
        System.out.println("Pongal");
        break;

    case 4:
        System.out.println("Poori");
        break;

    default:
        System.out.println("Invalid Choice");
    }
}

📤 Output

Pongal

📅 Scenario 2: Day of the Week System
`❓ Question

1 → Monday
2 → Tuesday
…
7 → Sunday`

private void scenario2() {

    int day = 1;

    switch (day) {

    case 1:
        System.out.println("Sunday");
        break;

    case 2:
        System.out.println("Monday");
        break;

    case 3:
        System.out.println("Tuesday");
        break;

    case 4:
        System.out.println("Wednesday");
        break;

    case 5:
        System.out.println("Thursday");
        break;

    case 6:
        System.out.println("Friday");
        break;

    case 7:
        System.out.println("Saturday");
        break;

    default:
        System.out.println("Invalid Day");
    }
}

📤 Output

Sunday

📱 Scenario 3: Mobile Recharge Plan

`❓ Question

199 → 1GB/day
399 → 2GB/day
599 → 3GB/day`

private void scenario3() {

    int plan = 399;

    switch (plan) {

    case 199:
        System.out.println("1GB/day");
        break;

    case 399:
        System.out.println("2GB/day");
        break;

    case 599:
        System.out.println("3GB/day");
        break;

    default:
        System.out.println("Plan not available");
    }
}

📤 Output

2GB/day

🧑‍💼 Scenario 4: Employee Role Access
`❓ Question

ADMIN → Full access
MANAGER → Limited access
EMPLOYEE → Basic access`

private void scenario4() {

    String role = "ADMIN";

    switch (role) {

    case "ADMIN":
        System.out.println("Full Access");
        break;

    case "MANAGER":
        System.out.println("Limited Access");
        break;

    case "EMPLOYEE":
        System.out.println("Basic Access");
        break;

    default:
        System.out.println("No Access");
    }
}

📤 Output

Full Access

🚦 Scenario 5: Traffic Fine System
`❓ Question

1 → No helmet
2 → No seatbelt
3 → Signal jump
4 → Over speed`

private void scenario5() {

    int code = 2;

    switch (code) {

    case 1:
        System.out.println("No Helmet Fine");
        break;

    case 2:
        System.out.println("No Seatbelt Fine");
        break;

    case 3:
        System.out.println("Signal Jump Fine");
        break;

    case 4:
        System.out.println("Over Speed Fine");
        break;

    default:
        System.out.println("Invalid Violation");
    }
}

📤 Output

No Seatbelt Fine

⚠️ Important Concept: Fall Through

int x = 1;

switch(x) {
    case 1:
        System.out.println("A");
    case 2:
        System.out.println("B");
}

📤 Output

A
B

👉 Because break is missing

🧠 Key Takeaways

✔ Switch is cleaner than multiple if-else
✔ break prevents unwanted execution
✔ default works like else
✔ Works with int, char, String
✔ Curly braces {} are mandatory
✔ continue is not directly used in switch

🏁 Conclusion

Today I understood how to use switch-case effectively in Java.

This is very useful in automation for:

✔ Menu selection
✔ Handling multiple conditions
✔ Writing clean and readable code

Step by step, I’m improving my Java logic for automation testing 🚀

🤖 A Small Note

I used ChatGPT to help structure and refine this blog while ensuring the concepts remain aligned with my trainer’s explanations.

🚀 Day 21 of My Automation Journey – If / Else Tricky Questions

bala d kaveri — Wed, 25 Mar 2026 06:39:30 +0000

Today I explored some tricky and confusing scenarios in Java if / else statements.

At first, if-else looks simple… but small mistakes in syntax, conditions, or indentation can completely change the output 😲

So I practiced 12 tricky questions to understand how Java actually executes them.

🔹 What is if Statement?

✔ Executes code only when condition is true

🔍 Scenario 1

int x = 5;

if (x > 2)
    System.out.println("Hello");

✅ Explanation
5 > 2 → true

📤 Output

Hello

🔍 Scenario 2

int x = 5;

if (x < 2)
    System.out.println("Hello");

System.out.println("Hi");

✅ Explanation

5 < 2 → false → if block skipped

But the second statement is outside if, so it executes.

📤 Output

Hi

🔍 Scenario 3

if(true)
{
    System.out.println("Hello");
}

✅ Explanation

Condition is always true

📤 Output

Hello

🔍 Scenario 4

if(false)
{
    System.out.println("Hello");
}

✅ Explanation

Condition is always false

📤 Output

(No Output)

🔍 Scenario 5

int x = 5;

if (x > 2)
    System.out.println("Hello");
else
    System.out.println("Hi");

✅ Explanation
5 > 2 → true
📤 Output

Hello

🔍 Scenario 6 (Important ⚠️)

int x = 10;

if (x = 20) {
    System.out.println("True");
}

❌ Explanation
x = 20 → Assignment, NOT comparison
Java expects boolean condition, but x = 20 returns int.

📤 Result

Compile Time Error

👉 Correct way:

if (x == 20)

🔍 Scenario 7 (Dangling Else Problem)

int x = 5;

if (x > 2)
    if (x < 10)
        System.out.println("A");
    else
        System.out.println("B");

✅ Explanation
if (x > 2) → true if (x < 10) → true

👉 else always attaches to the nearest if

📤 Output

🔍 Scenario 8

int a = 0;

if (a)
    System.out.println("Yes");
else
    System.out.println("No");

❌ Explanation

`Java does NOT allow:

if(a)

Condition must be boolean`

📤 Result

Compile Time Error

🔍 Scenario 9 (Very Important 🔥)

int x = 0;

if (x++ == 0 && ++x == 2)
    System.out.println("True");

System.out.println(x);

✅ Explanation

`Step by step:

x = 0

x++ == 0 → true (x becomes 1)
++x == 2 → x becomes 2 → true

Both conditions true → print "True"`

📤 Output

True
2

🔍 Scenario 10 (Short Circuit OR)

int x = 10;

if (x == 10 || x++ == 11)
    System.out.println(x);

✅ Explanation
`x == 10 → true

👉 OR (||) stops execution if first condition is true
👉 x++ is NOT executed`

📤 Output

🔍 Scenario 11 (Common Mistake ⚠️)

int x = 5;

if (x > 2)
    System.out.println("A");
    System.out.println("B");

✅ Explanation
Only first line is part of if Second line always executes
📤 Output

A
B

🔍 Scenario 12 (Nested if)

int x = 10, y = 5;

if (x > y)
    if (y > 0)
        if (x > 20)
            System.out.println("A");
        else
            System.out.println("B");

✅ Explanation
x > y → true y > 0 → true x > 20 → false

So else executes.

📤 Output

🧠 Key Takeaways

✔ if works only with boolean conditions
✔ = is assignment, == is comparison
✔ else always binds to nearest if
✔ Without {}, only one statement belongs to if
✔ Short-circuit operators (&&, ||) can skip execution
✔ Increment operators (++) change values during evaluation

🏁 Conclusion

Today’s session helped me understand how small syntax differences can completely change program behaviour.

These tricky questions are very useful for:

✔ Java interviews
✔ Writing correct automation logic
✔ Debugging real-world code

Step by step, I’m becoming more confident in Java fundamentals for automation testing 🚀

🤖 A Small Note

I used ChatGPT to help structure and refine this blog while ensuring the concepts remain aligned with my trainer’s explanations.

🚀 Day 20 of My Automation Journey – Control Flow Statements (if, else if, else).

bala d kaveri — Wed, 25 Mar 2026 06:29:04 +0000

Today I explored one of the most important concepts in Java – Control Flow Statements.

Control flow statements help us decide:

👉 Which code should execute
👉 When it should execute
👉 How many times it should execute

These are very important when building real-world applications and automation scripts.

🔹 What are Control Flow Statements?

Control flow statements control the execution flow of a program.
**
There are 3 types:**

1️⃣ Decision Making Statements
2️⃣ Looping Statements
3️⃣ Jump Statements

🔐 1️⃣ Decision Making Statements

Used to take decisions based on conditions.

✅ if

Executes code only if condition is true

✅ else-if

Used to check multiple conditions

✅ else

Executes when all conditions fail

✅ switch

Used for multiple fixed values

🔁 2️⃣ Looping Statements

✔ while loop
✔ for loop
✔ do-while loop

🔄 3️⃣ Jump Statements

| Statement  | Purpose         |
| ---------- | --------------- |
| `break`    | Stops loop      |
| `continue` | Skips iteration |

💡 Scenario-Based Questions (if / else-if / else)
🏦 Scenario 1: ATM Withdrawal System
❓ Question

A user tries to withdraw money from an ATM.
If withdrawal amount is less than or equal to balance → show "Successfully debited"
Else → show "Insufficient balance"

private void scenario1() {

    int balance = 1000;
    int userWA = 200;

    if (userWA <= balance) {
        System.out.println("Successfully Debited " + userWA);
    } else {
        System.out.println("Insufficient Balance");
    }
}

🔍 Explanation

✔ Condition checks whether user has enough balance
✔ Executes appropriate block based on result

📤 Output

Successfully Debited 200

🍔 Scenario 2: Online Food Delivery Status
❓ Question

An order goes through multiple stages:
If "Placed" → show Waiting for confirmation
If "Preparing" → show Food is being prepared
If "Out for delivery" → show Delivery partner on the way
Else → show Delivered

private void scenario2(String userState) {

    if (userState.equalsIgnoreCase("placed")) {
        System.out.println("Waiting for restaurant confirmation");
    } else if (userState.equalsIgnoreCase("preparing")) {
        System.out.println("Food is being prepared");
    } else if (userState.equalsIgnoreCase("out for delivery")) {
        System.out.println("Delivery partner on the way");
    } else {
        System.out.println("Delivered");
    }
}

🔍 Explanation

✔ Uses else-if ladder for multiple conditions
✔ equalsIgnoreCase() handles case sensitivity

🎓 Scenario 3: Exam Result System
❓ Question

A student’s result is based on marks:
< 35 → Fail 35–60 → Pass 60–80 → First Class 80 → Distinction

private void scenario3() {

    int mark = 81;

    if (mark < 35)
        System.out.println("Fail");
    else if (mark >= 35 && mark <= 60)
        System.out.println("Pass");
    else if (mark > 60 && mark <= 80)
        System.out.println("First Class");
    else
        System.out.println("Distinction");
}

🔍 Explanation

✔ Uses range conditions with && operator
✔ Ensures only one block executes

📤 Output

Distinction

🚦 Scenario 4: Traffic Signal Control
❓ Question

A driver reacts based on signal color:
Red → Stop Yellow → Get ready Green → Go Else → Invalid signal

private void scenario4(String signalcolor) {

    if (signalcolor.equalsIgnoreCase("red"))
        System.out.println("Stop the Vehicle");
    else if (signalcolor.equalsIgnoreCase("yellow"))
        System.out.println("Get Ready");
    else if (signalcolor.equalsIgnoreCase("green"))
        System.out.println("Go");
    else
        System.out.println("Invalid Signal");
}

🔍 Explanation

✔ Uses string comparison
✔ Handles different input cases using equalsIgnoreCase()

🔐 Scenario 5: Login Authentication System
❓ Question

A user tries to log in:

If username is wrong → "Invalid Username" Else if password is wrong → "Invalid Password" Else if account is locked → "Account Locked" Else → Allow login static String username = "bala"; static String password = "bala1234"; static boolean accountLocked = true;

public class Decisionmaking {

    static String username = "bala";
    static String password = "bala1234";
    static boolean accountLocked = true;
    public static void main(String[] args) {
        Decisionmaking demo = new Decisionmaking();
        demo.sceanrio5();
private void scenario5() {

    if (!username.equals("bala"))
        System.out.println("Invalid Username");
    else if (!password.equals("bala1234"))
        System.out.println("Invalid Password");
    else if (accountLocked)
        System.out.println("Account is Locked");
    else
        System.out.println("Allow login");
}

🔍 Explanation

✔ ! operatoris used for negation
✔ Conditions are evaluated in sequence
✔ Once matched → remaining conditions are skipped

📤 Output

Account is Locked

🧠 Key Takeaways

✔ Control flow defines how program executes
✔ if-else handles decision making
✔ else-if handles multiple conditions
✔ Loops reduce repetitive code
✔ break & continue control loops

🏁 Conclusion

Today’s learning helped me understand how Java programs make decisions and control execution flow.

These concepts are extremely important in automation testing, where we need to:

✔ Handle different test conditions
✔ Validate application behavior
✔ Write dynamic scripts

Step by step, I’m building a strong foundation in Java for Selenium Automation 🚀

🤖 A Small Note

I used ChatGPT to help structure and refine this blog while ensuring the concepts remain aligned with my trainer’s explanations.

🚀 Day 19 of My Automation Journey – Method Overloading Tricky Questions

bala d kaveri — Mon, 16 Mar 2026 17:06:17 +0000

Today I practiced some tricky scenarios of Java Method Overloading.

Method overloading is a very common concept in Java, but the way Java decides which method to call can sometimes be confusing.

So I explored 15 scenarios to understand how Java selects the correct method during compile time.

🔹 What is Method Overloading?

Method Overloading means:

✔ Same method name
✔ Different parameters (type / number / order)

Example:

class Test1 {

    void show(int a){
        System.out.println("int method called");
    }

    void show(double a){
        System.out.println("double method called");
    }

    public static void main(String[] args) {
        Test1 t = new Test1();
        t.show(10);
    }
}

Explanation

10 is an int literal, so Java finds the exact match.

Output

int method called

🧠 Java Method Selection Priority

When multiple overloaded methods exist, Java follows this priority order:

1️⃣ Exact Match
2️⃣ Widening
3️⃣ Autoboxing
4️⃣ Varargs

🧠 Java Method Overloading Priority Table

| Priority        | Rule            | Description                                                                           | Example                        |
| --------------- | --------------- | ------------------------------------------------------------------------------------- | ------------------------------ |
| 1️⃣ Highest      | Exact Match     | Java first looks for a method whose parameter type exactly matches the argument type. | `show(int a)` called with `10` |
| 2️⃣              | Widening        | If exact match is not found, Java converts the argument to a larger compatible type.  | `int → long`, `int → double`   |
| 3️⃣              | Autoboxing      | Java converts primitive types into wrapper classes automatically.                     | `int → Integer`                |
| 4️⃣ Lowest       | Varargs         | If none of the above matches, Java chooses the variable-length argument method.       | `show(int... a)`               |

📊 Quick Example of the Priority

| Method Available                | Call       | Java Chooses                           |
| ------------------------------- | ---------- | -------------------------------------- |
| `show(int)` and `show(long)`    | `show(10)` | `show(int)` (Exact Match)              |
| `show(long)` and `show(double)` | `show(10)` | `show(long)` (Widening)                |
| `show(Integer)` and `show(int)` | `show(10)` | `show(int)` (Exact Match > Autoboxing) |
| `show(int)` and `show(int...)`  | `show(10)` | `show(int)` (Exact Match > Varargs)    |

⚠️ Special Case: Ambiguous Method

| Scenario                                                      | Result                 |
| ------------------------------------------------------------- | ---------------------- |
| Two methods match equally                                     | **Compile Time Error** |
| Example: `show(String)` and `show(Integer)` with `show(null)` | Java cannot decide     |

✅ One-line Memory Trick

`Exact Match → Widening → Autoboxing → Varargs`

🔎 Scenario 1

class Test1 {

    void show(int a){
        System.out.println("int method called: " + a);
    }

    void show(long a){
        System.out.println("long method called: " + a);
    }

    public static void main(String[] args) {
        Test1 t = new Test1();
        t.show(10);
    }
}

Explanation
10 → int

Available methods:

show(int) show(long)

Java selects the exact match, which is show(int).

Output

int method called: 10

🔎 Scenario 2

class Test2 {

    void show(Integer a){
        System.out.println("Integer method called");
    }

    void show(int a){
        System.out.println("int method called");
    }

    public static void main(String[] args) {
        Test2 t = new Test2();
        t.show(10);
    }
}

Explanation
10 → int

Possible matches:

int → int (Exact Match) int → Integer (Autoboxing)

Java prefers Exact Match over Autoboxing.

Output

int method called

🔎 Scenario 3

class Test3 {

    void show(int a, float b){
        System.out.println("int float method");
    }

    void show(float a, int b){
        System.out.println("float int method");
    }

    public static void main(String[] args) {
        Test3 t = new Test3();
        t.show(10,10);
    }
}

Explanation
show(int,float) show(float,int)

Both methods require type conversion, so Java cannot decide which is better.

Result
Compile Time Error
Reference to show is ambiguous
🔎 Scenario 4

class Test4 {

    void show(int... a){
        System.out.println("varargs method");
    }

    void show(int a){
        System.out.println("single int method");
    }

    public static void main(String[] args) {
        Test4 t = new Test4();
        t.show(10);
    }
}

Explanation

Available methods:

show(int) show(int...)

Java prefers Exact Match over Varargs.

Output

single int method

🔎 Scenario 5

class Test5 {

    void show(int a){
        System.out.println("single int method");
    }

    void show(int... a){
        System.out.println("varargs method");
    }

    public static void main(String[] args) {
        Test5 t = new Test5();
        t.show();
    }
}

Explanation
show(int) → requires argument ❌ show(int...) → accepts zero arguments ✔
Output

varargs method

🔎 Scenario 6

class Test6 {

    void show(double a){
        System.out.println("double method");
    }

    void show(float a){
        System.out.println("float method");
    }

    public static void main(String[] args) {
        Test6 t = new Test6();
        t.show(10);
    }
}

Explanation
10 → int

Possible widening:

int → float int → double

Java prefers the smaller widening conversion.

Output

float method

🔎 Scenario 7

class Test7 {

    void show(Object o){
        System.out.println("Object method");
    }

    void show(String s){
        System.out.println("String method");
    }

    public static void main(String[] args) {
        Test7 t = new Test7();
        t.show(null);
    }
}

Explanation
null → matches Object and String

But:

String is more specific than Object
Output

String method

🔎 Scenario 8

class Test8 {

    void show(String s){
        System.out.println("String method");
    }

    void show(Integer i){
        System.out.println("Integer method");
    }

    public static void main(String[] args) {
        Test8 t = new Test8();
        t.show(null);
    }
}

Explanation
`null → matches both String and Integer

Neither is more specific.`

Result
Compile Time Error
Reference to show is ambiguous
🔎 Scenario 9

class Test9 {

    void show(int a,int b){
        System.out.println("two int method");
    }

    void show(int... a){
        System.out.println("varargs method");
    }

    public static void main(String[] args) {
        Test9 t = new Test9();
        t.show(10,20);
    }
}

Explanation

Possible methods:

show(int,int) show(int...)

Java prefers exact match.

Output

two int method

🔎 Scenario 10

class Test10 {

    void show(int a) {
        System.out.println("int a");
    }

    static void show(int a) {
        System.out.println("int a static method");
    }

    public static void main(String[] args) {
        Test10 t = new Test10();
        t.show(10);
    }

}

Explanation

Java does not allow overloading based only on static vs non-static.

Result
Compile Time Error
method show(int) is already defined
🔎 Scenario 11

class Test11 {

    void show(long a){
        System.out.println("long method");
    }

    void show(float a){
        System.out.println("float method");
    }

    public static void main(String[] args) {
        new Test11().show(10);
    }
}

Explanation
10 → int

Possible widening:

int → long int → float

Java prefers long conversion.

Output

long method

🔎 Scenario 12

class Test12 {

    void show(int a){
        System.out.println("single int method");
    }

    void show(int a,int... b){
        System.out.println("int with varargs");
    }

    public static void main(String[] args) {
        new Test12().show(10);
    }
}

Explanation

Possible methods:

show(int) show(int,int...)

Java prefers exact match.

Output

single int method

🔎 Scenario 13

class Test13 {

    void show(char c){
        System.out.println("char method");
    }

    void show(int i){
        System.out.println("int method");
    }

    public static void main(String[] args) {
        new Test13().show('A');
    }
}

Explanation
'A' → char

Exact match exists.

Output

char method

🔎 Scenario 14

class Test14 {

    void show(byte b){
        System.out.println("byte method");
    }

    void show(short s){
        System.out.println("short method");
    }

    public static void main(String[] args) {

        byte b = 10;
        new Test14().show(b);

    }
}

Explanation
b → byte

Exact match exists.

Output

byte method

🔎 Scenario 15

class Test15 {

    void show(Object o){
        System.out.println("Object method");
    }

    void show(String s){
        System.out.println("String method");
    }

    void show(CharSequence c){
        System.out.println("CharSequence method");
    }

    public static void main(String[] args) {
        new Test15().show("Java");
    }
}

Explanation

Hierarchy:

Object ↑ CharSequence ↑ String

Java always chooses the most specific method.

Output

String method

🧠 Key Takeaways

✔ Java always selects the most specific method
✔ Exact match has highest priority
✔ Widening happens before autoboxing
✔ Varargs has lowest priority
✔ Ambiguous calls cause compile-time errors

🏁 Conclusion

Today’s learning session helped me understand how Java resolves overloaded methods internally.

These tricky scenarios are very common in Java interviews and real-world development, especially when working with frameworks and libraries.

Mastering these concepts will help me build strong Java fundamentals for Selenium Automation Testing.

🤖 A Small Note

I used ChatGPT to help structure and refine this blog while ensuring the concepts remain aligned with my trainer’s explanations.

DEV Community: bala d kaveri

🚀 Day 29 of My Automation Journey – Arrays (Full Guide + Tricky Questions)

🔹 PART A – ARRAYS COMPLETE THEORY

🔹 1. What is an Array?

🔹 2. What Happens Internally (JVM 🔥)

🔹 3. Proof – Array is an Object

Output:

🔹 4. Array Creation

🔹 5. Important Points ⚠️

🔹 6. Default Values

🔹 7. Initialization & Access

🔹 8. Looping Through Array

Normal Loop:

Enhanced Loop:

🔹 9. Multi-Dimensional Array

🔹 PART B – PROGRAMS

✅ Program 1 – Default Values

Output:

❌ Program 2 – Index Error

Output:

❌ Program 3 – Length Modification

Output:

🔥 Program 4 – Reference Behavior

Output:

🔥 Program 5 – Comparing Arrays

Output:

❌ Program 6 – Null Array

Output:

❌ Program 7 – Negative Size

Output:

🔹 PART C – PRACTICE PROGRAM

🔍 Output Insight

🔹 PART D – MEMORY & ADVANCED CONCEPTS

Separate Memory

Passing Array

🔹 PART E – TRICKY QUESTIONS

❓ Q1

❓ Q2

❓ Q3

❓ Q4

❓ Q5

❓ Q6

❓ Q7

🔹 PART F – public static void main (DETAILED 🔥)

🔍 Deep Breakdown

🔹 public

🔹 static

🔹 void

🔹 main

🔹 String[] args

💡 Important Insight

🔚 FINAL TAKEAWAYS

💡 GOLDEN INSIGHT

🚀 Day 28 of My Automation Journey – Nested For Loop

🔹 1. What is a Nested Loop?

💡 Structure:

🧠 How It Works

🔹 2. Basic Example (Print 1’s)

📤 Output:

🔹 3. Print Row Number

📤 Output:

🔹 4. Print Column Number

📤 Output:

🔹 5. Rectangle Pattern ⭐

📤 Output:

🔹 6. Reverse Triangle Pattern 🔻

📤 Output:

🔹 7. Triangle Pattern 🔺

📤 Output:

🔍 Key Concept (Very Important 🔥)

⚠️ Common Mistake

🔹 Real Understanding Trick 💡

🔚 Final Takeaways

💡 Golden Insight

🚀 Day 27 of My Automation Journey – Introduction to Selenium & Maven Setup

🔹 1. What is Selenium?

💡 In simple terms:

🔹 2. Why Selenium?

🔹 3. Setting Up Selenium using Maven

🔹 4. Understanding pom.xml File

🔹 4. Understanding `pom.xml` File

💻 Sample `pom.xml`:

🔹 3. Removing Curly Braces `{ }`