Forem: Ranjith Ranjith

Java-8 (The Biggest Transformation)

Ranjith Ranjith — Wed, 17 Dec 2025 13:14:10 +0000

DEV
Java 8 is the update that completely changed how Java developers write code. It took Java from “old-school, verbose, class-heavy” to clean, modern, expressive.

Today we starts with LAMBDA EXPRESSION(Part-1)

In Java, writing even a small piece of logic used to be lengthy because we had to create an anonymous class and override its method every single time. Java 8 solved this problem by introducing lambda expressions — a short, clean, functional‑style way to write code.

Basic Syntax
(parameters)−>body

Variations
No parameter- ()->System.out.println("HI");
One parameter-x->x*x;
Multiple parameter- (x,y)->x*y;
// with blocks with parameter return is must
With Blocks- x->{int y=x+1; return y;};
// with blocks with void return is no need
with Blocks with void- ()->{ system.out.println("HI"); }

Before 8:

new Thread(new Runnable() {
@override
public void run() {
System.out.println("Running");
}
}).start();
After 8:

new Thread(() -> System.out.println("Running")).start();

Capturing variables

Rule: Variable must be “effectively final”

int processedCount = 0;

orders.forEach(order -> {
processedCount++; // ❌ ERROR
});
Local variable processedCount defined in an enclosing scope must be final or effectively final
How to fix,

Fix 1: Use AtomicInteger

AtomicInteger processedCount = new AtomicInteger(0);

orders.forEach(order -> {
processedCount.incrementAndGet(); // ✔ Works
});
Atomic Integer is an object.

Java allows change the variable

Because Object reference is final but we change the values.

AtomicInteger sum = new AtomicInteger(0);

list.forEach(n -> sum.addAndGet(n));

System.out.println(sum.get());

Fix 2: Use array wrapper

int[] processedCount = {0};

orders.forEach(order -> {
processedCount[0]++; // ✔ Works
});
Any reference is final we change their values so we can do

Fix 3: Use Stream count

long processedCount = orders.stream().count();

Hope this helped you understand Java 8 better.
In the next blog, we dive into another Java 8 Topic—don’t miss it!

TODAY TRY ONE STRING PROGRAM IN REVERSE WORD

Ranjith Ranjith — Tue, 09 Dec 2025 05:16:27 +0000

Today I tried this string program and I got the correct output by myself. I feel very happy."

    String name="ranjith kumar";
    char[] ch=  name.toCharArray();
    int start=0;
    for(int i=0;i<ch.length;i++) {
        if(i==ch.length-1||ch[i]==' ') {
            int end;
            if(i==ch.length-1) {
                end=i;
            }
            else {
                end=i-1;
            }
            while(start<end) {
                char temp=ch[start];
                ch[start]=ch[end];
                ch[end]=temp;
                start++;
                end--;
            }
            start=i+1;  
        }   
    }
    System.out.println(new String(ch)); 

      for(int j=0;j<ch.length;j++) {

           int st=0;

           int en=ch.length-1;

           while(st<en) {
                char temp=ch[st];
                ch[st]=ch[en];
                ch[en]=temp;
                st++;
                en--;
            }
            start=j+1;  
        }

-count by character-

public class CharactorByCount {

public static void main(String[] args) {

            String s="ranjith kumar";
        char[] ch=s.toCharArray();

        for(int i=0;i<ch.length;i++) {
          char  letter =ch[i];
          int count=1;

          if(letter!=' ') {
               for(int j=i+1;j<ch.length;j++) {     
                   if(letter==ch[j]) {
                    count++;
                    ch[j]=' ';
                   }
               }
           if(count>=1) {
             System.out.println(letter+"=="+count);
           }
          }
        }
}

}

08/12/2025

Ranjith Ranjith — Mon, 08 Dec 2025 14:29:14 +0000

Today my day started well.
I woke up early,
took a bath, brushed my teeth, prayed to all the gods, ate, and left for the institute.
On the way, there was a temple festival, and it was really nice.
It was a happy moment.

Today I also started studying.
I had a doubt in strings for a long time, and finally I learned that program today.
I’m really happy. Sathesh bro helped me a lot.

After finishing everything, I returned to room.
Overall, my day went really well. Thank you.

SOFT SQEUE INTERVIEW experience

Ranjith Ranjith — Sat, 06 Dec 2025 13:59:13 +0000

I attended an interview for a Software Development role. It was a really good company, and they even provided food for the candidates. I actually went there for a Java Developer position, but when I reached the venue, they informed me that the Java interviews were not being conducted that day.

Since I had already come all the way, I decided to make use of the opportunity and try the UI/UX interview instead. I attended the first round and, to my surprise, I got selected. In the second round, they asked me to create an application design using the Figma tool. I didn’t know anything about Figma before, but I still tried my best. Through this task, I gained some experience and finally understood what Figma is and how it works.

The company also provided lunch for all candidates, which was very helpful. Overall, it was a good learning experience for me.

NET AXIS IT SOLUCTION experience

Ranjith Ranjith — Sat, 06 Dec 2025 13:54:01 +0000

“Today I attended the interview at NetAxis. It went well. They asked all the questions in Tamil. They asked only basic questions like HTML, CSS, JavaScript, API, and OOPS. I think knowing these basics is enough to get selected.”

Minuscule Technologies, Chennai experience

Ranjith Ranjith — Sat, 06 Dec 2025 13:43:00 +0000

The interview went really well. The watchman was very respectful and polite. The staff also spoke kindly and treated me well. Overall, it felt like a very good and professional company. The questions were also very good. If I practice a little more, I can easily get selected in this company next time.

These are the questions they asked me, and my answers:

They asked for the multiples of prime numbers between 1 and 11.
They asked me to print a diamond pattern.
They asked me to write a simple login validation program.

I explained all these questions during the interview.

BASIC HR QUESTION AND ANSWER EXAMPLE :

Ranjith Ranjith — Sat, 06 Dec 2025 13:34:28 +0000

Why do you want to move from sales to IT?
I earned 40,000 salary in GRT and learned a lot in sales.
Every day was a new experience, and I worked there for 4 years.
But I am a Physics graduate, and I feel proud to say that I am a Software Developer.

than saying I work in GRT.

That’s why I want to start my career in the IT field.

postgresql (dml &ddl)

Ranjith Ranjith — Mon, 13 Oct 2025 11:05:55 +0000

DATA : information.

Database : is a place where we can store out data.

Types of database:
types:

Rdbms: relational database managnment systom.
- Rdbms : tables format (rows and columns). rdb type: example = mysql , oracle , microsoft server sql.

2) Ordbms = object relational database managnment systom.

      * postgresql  (only open sources)
      * graph database
      * mapping database

first of all what is sql ?
sql : structured query language // (neccessary details)
psql install : 2 type

      i)  cli: comment line interface
      ii)  ui: user interface

psql install step by step linux for (ui) method

       i)    start windows button
       ii)   search for software manager
       iii)  search for postgresql

cli method install for linux

        i)open terminal
        ii)sudo apt update 
        iii) sudo apt install postgresql 

 iv)  check status = (sudo systemctl status postgresql) 

go to the inside 
          v)   -i -u postgres
          vi)   psql

 corrently  inside  a what data base this postgres 
           i) \l        //it will list all tha data base

            ii)\q        // just exit

              iii) create database student;

               iv) \c student;
      sql:

            1) data reterievel language/query language
            2) data manipilation language
                 * inselt,delete,update
            3) data definition language
                 * create,alter,drop,truncate

drop : drop tha table
truncate : remove tha inner all datas

            4) data control language
                    grant,revoke
            5) data transaction language
                    commit, rollback 



          (i) : create table student ( sno int, name varchar(30),age int,trainer varchar(20),doj date;

         ii) \dt        // (one database inside ,i need see this how many table )

          iii) inselt into student values ( 1, 'ranjith', 25, 'prithivi', '2025-09-25';

           just check this (select * from student; )


            key point 

         i)   sudo -i -u postgres
         ii)  psql
         iii) \l                            //it will list all tha data base
         iv)  create database student;
         v)   \c student;                    //just check 
         vi)  create table student ( sno int, name varchar(30),age int,trainer varchar(20),doj date;
         vii) \dt  //(one database inside ,i need see this how many table )

         viii) inselt into student values ( 1, 'ranjith', 25, 'prithivi', '2025-09-25';

I need to create 3 users with different DML, DDL, DQL on newly created clean Database in PostgreSQL.

DML should have SELECT, UPDATE, DELETE
DDL should have CREATE, DROP, ALTER, TRUNCATE, INSERT
DQL should have SELECT

all of this in standard scheme public. Important is that user inherit right on newly created tables by DDL user.

           echeck p(select * from student; )

database name=grt
table name = scheme

s_no	group_code	name	date	mobile_number	age	amount
1	2527	Athavi	2025-08-11	7358956288	28	2000
2	2528	Karthik	2025-08-12	9876543210	30	1500
3	2529	Divya	2025-08-13	9123456789	27	20002
4	2530	Mani	2025-08-14	9988776655	32	1000
5	2531	Priya	2025-08-15	9234567890	26	6000
6	2532	Arun	2025-08-16	9345678901	29	8000
7	2533	Vijay	2025-08-17	9456789012	31	7000
8	2534	Sneha	2025-08-18	7358956288	24	2000
9	2535	ranjith	2025-08-19	6381952919	25	2000
10	2536	abdul	2525-08-20	7358952268	28	7000

DDL (Data Definition Language)

1) create
2) alter
3) drop
4) truncate

CREATE
Purpose: To create a new database object (table, view, schema, index).
Syntax (for table):
CREATE TABLE students (s_no INT PRIMARY KEY,name VARCHAR(50),age INT,dob DATE);
ALTER
Purpose: To modify an existing table (add, drop, or change columns).
CREATE

Purpose: To create a new database object (table, view, schema, index).

Syntax (for table)

CREATE TABLE scheme (
s_no INT PRIMARY KEY,
name VARCHAR(50),
age INT,
dob DATE
);

ALTER

Purpose: To modify an existing table (add, drop, or change columns).
add a column
ADD COLUMN mobile_number BIGINT;
Drop a column:

     ALTER TABLE scheme DROP COLUMN age;

DROP

Purpose: To delete a table or other database object permanently.

Syntax:

DROP TABLE scheme;

TRUNCATE

Purpose: To delete all rows from a tabDML (Data Manipulation Language)

 1) INSERT
 2) UPDATE
 3) DELETE
 4) SELECT

INSERT

Purpose: Add new rows into a table.

Syntax: INSERT INTO table_name
VALUES (value1, value2, ...)

UPDATE

Purpose: Modify existing data in a table.
Syntax: UPDATE scheme SET age = 25 WHERE s_no = 1;

DELETE

Purpose: Remove data rows from a table.

Syntax: delete from scheme

Select purpose: The SELECT statement is used to retrieve data from a database table

syxtax :
select * from scheme;

DDL (Data Definition Language)

DDL is the data definition language and is concerned with the SQL statements that modify how the data is stored. It includes CREATE, ALTER, and DROP.

DML replication
PGD doesn't replicate the DML statement. It replicates the changes caused by the DML statement. For example, an UPDATE that changed two rows replicates two changes, whereas a DELETE that didn't remove any rows doesn't replicate anything.

reffer :
https://www.enterprisedb.com/docs/pgd/latest/reference/appusage/dml-ddl/
https://www.geeksforgeeks.org/sql-ddl-dql-dml-dcl-tcl-commands/
https://stackoverflow.com/questions/74284045/create-dml-ddl-dql-user-in-postgresql
chatgpt :

RUN TIME EXCEPTION

Ranjith Ranjith — Thu, 02 Oct 2025 12:10:04 +0000

1) ArithmeticException: It is thrown when an exceptional condition has occurred in an arithmetic operation.
ex public class Example1 {
public static void main(String[] args) {
int a = 10, b = 0;
System.out.println(a / b); // divide by zero
}
}

2) ArrayIndexOutOfBoundsException: It is thrown to indicate that an array has been accessed with an illegal index. The index is either negative or greater than or equal to the size of the array.
ex
public class Example2 {
public static void main(String[] args) {
int arr[] = {1, 2, 3};
System.out.println(arr[5]);
}
}

3) ClassNotFoundException: This Exception is raised when we try to access a class whose definition is not found
ex
public class Example3 {
public static void main(String[] args) {
try {
Class.forName("MyClass");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
}

4) FileNotFoundException: This Exception is raised when a file is not accessible or does not open.
ex
import java.io.File;
import java.io.FileReader;

public class Example4 {
public static void main(String[] args) throws Exception {
FileReader fr = new FileReader(new File("abc.txt"));
}
}

5) IOException: It is thrown when an input-output operation failed or interrupted
ex
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Example5 {
public static void main(String[] args) throws Exception {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
br.close();
br.readLine(); // Already closed => IOException
}
}

6) InterruptedException: It is thrown when a thread is waiting, sleeping, or doing some processing, and it is interrupted.
ex
public class Example6 extends Thread {
public void run() {
try {
Thread.sleep(2000); // wait
System.out.println("Thread finished");
} catch (InterruptedException e) {
System.out.println("Thread interrupted");
}
}

public static void main(String[] args) {
    Example6 t = new Example6();
    t.start();
    t.interrupt(); 
}

}

7) NoSuchFieldException: It is thrown when a class does not contain the field (or variable) specified
ex
import java.lang.reflect.Field;

class Student {
int id;
}

public class Example7 {
public static void main(String[] args) throws Exception {
Field f = Student.class.getDeclaredField("name");
}
}

8) NoSuchMethodException: It is thrown when accessing a method that is not found.
ex
import java.lang.reflect.Method;

class Student {
public void display() {}
}

public class Example8 {
public static void main(String[] args) throws Exception {
Method m = Student.class.getDeclaredMethod("show");
}
}

9) NullPointerException: This exception is raised when referring to the members of a null object. Null represents nothing

public class Example9 {
public static void main(String[] args) {
String s = null;
System.out.println(s.length()); // null object access
}
}

10) NumberFormatException: This exception is raised when a method could not convert a string into a numeric format.
ex
public class Example10 {
public static void main(String[] args) {
String s = "abc";
int num = Integer.parseInt(s); //
}
}

11) RuntimeException: This represents an exception that occurs during runtime.
ex
public class Example11 {
public static void main(String[] args) {
throw new RuntimeException("Runtime exception example");
}
}

12) StringIndexOutOfBoundsException: It is thrown by String class methods to indicate that an index is either negative or greater than the size of the string
ex
public class Example12 {
public static void main(String[] args) {
String s = "java";
System.out.println(s.charAt(10));
}
}

13) IllegalArgumentException : This exception will throw the error or error statement when the method receives an argument which is not accurately fit to the given relation or condition. It comes under the unchecked exception.
ex
public class Example13 {
public static void main(String[] args) {
Thread t = new Thread();
t.setPriority(20);
}
}

14) IllegalStateException : This exception will throw an error or error message when the method is not accessed for the particular operation in the application. It comes under the unchecked exception.
ex
import java.util.*;

public class Example14 {
public static void main(String[] args) {
List list = new ArrayList<>();
Iterator it = list.iterator();
it.remove();
}
}

Tobe discuss : 6,7,8,13,14,

reffer:
https://www.geeksforgeeks.org/java/types-of-exception-in-java-with-examples/

EXCEPTION

Ranjith Ranjith — Sat, 27 Sep 2025 06:30:58 +0000

what is exception?
an exception is an abnormal event that occurs during the execution of a program which disrupts the normal flow of instructions. In simpler words, it’s a problem or error that happens while your program is running.
- why use ?
```
   We use exceptions in Java to handle errors and abnormal situations gracefully, instead of letting the program crash. Think of exceptions as a safety net for your program.     
```
  - when use exception?
```
 ou use exceptions whenever there’s a chance that the user might enter data in the wrong format, which would normally crash your program.
```
  Error
  
  1) System-level serious problem
  
  2) Cannot handle
  
  3) JVM, memory, hardware
  
  4) Examples OutOfMemoryError, StackOverflowError
  
  5) Usually program crash
```
 exception
```
  1) abnormal event
  2) Can handle using try-catch
  3) Programmer mistake, unexpected input
  4) ArithmeticException, NullPointerException
  5) Can continue if handled

Throw, and Try...Catch...Finally

The try statement defines a code block to run (to try).

The catch statement defines a code block to handle any error.

The finally statement defines a code block to run regardless of the result.

The throw statement defines a custom error.

Reffer;
https://www.w3schools.com/js/js_errors.asp

String buffer

Ranjith Ranjith — Sat, 27 Sep 2025 06:00:36 +0000

StringBuffer

a StringBuffer is a mutable sequence of characters.

Mutable → we can modify the content.

Thread-Safe → synchronized, so multiple threads can use it safely.

Slower compared to StringBuilder because of synchronization.

Call Conversation Example for useing for tamil medium

Ranjith Ranjith — Fri, 26 Sep 2025 13:29:49 +0000

You: Hello, am I speaking with [HR’s name]?

HR: Yes, this is [HR’s name], please tell me.

You: My name is [Your Name]. I got your contact details from Naukri. I just wanted to check if there are any fresher job openings in your company.

HR: Okay, which position are you looking for?

You: I am a 2021 passed-out graduate in [Your Degree/Stream]. I am looking for opportunities in [your field, e.g., software development / IT support / web development].

HR: Alright. Can you share your resume with me?

You: Sure, I’ll send you my updated resume to your email. Could you please confirm the email ID?

HR: Yes, it’s [HR’s email].

You: Thank you so much. I’ll share my resume right away. Looking forward to hearing from you.

HR: Okay, we’ll get back to you if there’s a suitable opening.

You: Thank you for your time. Have a nice day!