Handwritten Java Code for Beginners. Includes Arrays, Methods.

JAVA MATRIX & ARRAY OPERATIONS
Professional Developer Portfolio

Advanced Java Programming Tasks Collection



Prepared By: Student Developer
Subject: Java Programming
Category: Arrays & Matrix Operations
Document Type: Professional Code Documentation
Academic Session: 2026



A professionally formatted collection of Java programming tasks demonstrating array
manipulation, matrix operations, rotations, validations, replacements, and mathematical
computations.


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Table of Contents
1. Task 1 – Two-Dimensional Array Input & Output
2. Task 2 – Sum & Average of Array Elements
3. Task 3 – Matrix Rotation Program
4. Task 4 – Replace Negative Values with Zero
5. Task 5 – Swap First & Last Row
6. Task 6 – Matrix Addition Program




Task 1 – Two-Dimensional Array Input & Output

import java.util.Scanner;

public class Task1 {

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

System.out.println("Enter the number of rows: ");
int row = input.nextInt();




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, System.out.println("Enter the number of columns: ");
int col = input.nextInt();

int[][] array = new int[row][col];


fillArray(array);
printArray(array);
}


static void fillArray(int[][] array) {
Scanner input = new Scanner(System.in);

for (int i = 0; i < array.length; ++i) {
for (int j = 0; j < array[i].length; ++j) {
System.out.println(
"Enter the value for index " + (1 + j) +
" of row at index " + (1 + i) + ": "
);

array[i][j] = input.nextInt();
}
}
}

static void printArray(int[][] array) {
for (int i = 0; i < array.length; ++i) {
for (int j = 0; j < array[i].length; ++j) {
System.out.print(array[i][j] + " ");
}
System.out.println();
}
}
}




Task 2 – Sum & Average of Array Elements

import java.util.Scanner;

public class Task2 {

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

System.out.println("Enter the number of rows: ");




2