30 Days of Learning Java

A personal challenge to learn Java through consistent daily practice while building strong programming fundamentals.

About

This repository documents my 30-day Java learning journey. Each day I learn new concepts, write code by hand, and focus on understanding how programs work rather than simply copying solutions.

I'm using:

• Java
• Maven
• Git
• GitHub
• VS Code

The goal is to build a solid foundation in programming and software development through daily practice.

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Goals

• Learn Java fundamentals
• Develop problem-solving skills
• Understand object-oriented programming
• Learn Maven project management
• Become comfortable with Git and GitHub
• Build consistent coding habits

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Progress

Day	Topic	Project
1	Variables, Data Types, User Input, Scanner	PersonalInfo
2	if/else Statements, Comparison Operators	TemperatureConverter
3	Loops, Accumulators, Grade Calculations	GradeCalculator
4	ArrayLists, loops, finding max/min, average calculations	GradeManager
5	Methods, parameters, returning values	GradeCalculatorWithMethods

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Projects

Day 1 — PersonalInfo

Concepts learned:

• Packages
• Imports
• Variables
• Data types (String, int)
• User input with Scanner
• Output with System.out.print() and System.out.println()

Program features:

• Asks for a user's name
• Asks for their age
• Asks for their favorite color
• Displays the information back to the user

Find: src/main/java/com/learning/PersonalInfo.java

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Day 2 — TemperatureConverter

Concepts learned:

• Comparison operators
• Conditional logic
• if, else if, and else
• Basic mathematical formulas

Program features:

• Converts Celsius to Fahrenheit
• Categorizes temperature as cold, mild, or hot

Find: src/main/java/com/learning/TemperatureConverter.java

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Day 3 — GradeCalculator

Concepts learned:

• for loops
• Accumulators
• Repeated user input
• Average calculations
• Multi-branch conditional logic

Program features:

• Accepts multiple student grades
• Calculates class average
• Assigns a letter grade based on the average

Find: src/main/java/com/learning/GradeCalculator.java

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Day 4 — GradeManager

Concepts learned:

• ArrayLists
• for loops with lists
• indexing lists
• finding sum of values
• finding max and min values
• basic data processing

Program features:

• Stores multiple student grades
• Asks user how many grades to enter
• Displays all grades entered
• Calculates average grade
• Finds highest grade
• Finds lowest grade

Find: src/main/java/com/learning/GradeManager.java

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Day 5 — GradeCalculatorWithMethods

Concepts learned:

• Methods (functions)
• Returning values from methods
• Parameters
• Breaking programs into smaller parts
• Reusing code
• ArrayList with methods

Program features:

• Stores multiple student grades
• Uses methods to organize the program
• Calculates average grade
• Finds highest grade
• Finds lowest grade
• Displays all grades entered

Find: src/main/java/com/learning/GradeCalculatorWithMethods.java