Serialization & Data Formats

Serialization converts Java objects into a format that can be stored or transmitted, and deserialization converts them back. Understanding data formats (CSV, JSON-like) is essential for real-world data exchange. This is a foundational concept in enterprise application development that professional developers rely on daily. The explanations below are written to be beginner-friendly while covering the depth and nuance that comes from real-world Java experience. Take your time with each section and practice the examples

35 min•By Priygop Team•Last updated: Feb 2026

Working with CSV Data

Example

import java.util.*;

public class CSVProcessor {
    // Parse CSV line (simple implementation)
    static String[] parseCSV(String line) {
        return line.split(",");
    }
    
    // Format as CSV
    static String toCSV(String[] fields) {
        return String.join(",", fields);
    }
    
    public static void main(String[] args) {
        // Sample CSV data
        String[] csvData = {
            "Name,Department,Salary",
            "Alice,Engineering,85000",
            "Bob,Marketing,72000",
            "Charlie,Engineering,92000",
            "Diana,HR,68000",
            "Eve,Engineering,88000"
        };
        
        // Parse and display
        System.out.println("=== Employee Data ===");
        String[] headers = parseCSV(csvData[0]);
        
        double totalSalary = 0;
        int empCount = 0;
        
        for (int i = 1; i < csvData.length; i++) {
            String[] fields = parseCSV(csvData[i]);
            System.out.println(fields[0] + " | " + fields[1] + " | $" + fields[2]);
            totalSalary += Double.parseDouble(fields[2]);
            empCount++;
        }
        
        System.out.println("\nTotal employees: " + empCount);
        System.out.println("Average salary: $" + String.format("%.0f", totalSalary / empCount));
        
        // Filter by department
        String targetDept = "Engineering";
        System.out.println("\n" + targetDept + " team:");
        for (int i = 1; i < csvData.length; i++) {
            String[] fields = parseCSV(csvData[i]);
            if (fields[1].equals(targetDept)) {
                System.out.println("  " + fields[0] + ": $" + fields[2]);
            }
        }
    }
}

Try It Yourself: Data Transformer

Try It Yourself: Data TransformerJava

Java Editor

✓ ValidTab = 2 spaces

import java.util.*;

public class DataTransformer {
    public static void main(String[] args) {
        // Transform between data formats
        String[][] employees = {
            {"Alice", "Engineering", "85000"},
            {"Bob", "Marketing", "72000"},
            {"Charlie", "Engineering", "92000"},
            {"Diana", "HR", "68000"},
        };
        
        // Convert to CSV format
        System.out.println("=== CSV Format ===");
        System.out.println("Name,Department,Salary");
        for (String[] emp : employees) {
            System.out.println(String.join(",", emp));
        }
        
        // Convert to table format
        System.out.println("\n=== Table Format ===");
        System.out.printf("%-10s %-15s %-10s%n", "Name", "Department", "Salary");
        System.out.println("-".repeat(35));
        for (String[] emp : employees) {
            System.out.printf("%-10s %-15s $%-9s%n", emp[0], emp[1], emp[2]);
        }
        
        // Convert to simple JSON-style format
        System.out.println("\n=== JSON-Style Format ===");
        System.out.println("[");
        for (int i = 0; i < employees.length; i++) {
            String comma = (i < employees.length - 1) ? "," : "";
            System.out.println("  { \"name\": \"" + employees[i][0] + 
                "\", \"dept\": \"" + employees[i][1] + 
                "\", \"salary\": " + employees[i][2] + " }" + comma);
        }
        System.out.println("]");
    }
}

import java.util.*;

public class DataTransformer {
    public static void main(String[] args) {
        // Transform between data formats
        String[][] employees = {
            {"Alice", "Engineering", "85000"},
            {"Bob", "Marketing", "72000"},
            {"Charlie", "Engineering", "92000"},
            {"Diana", "HR", "68000"},
        };
        
        // Convert to CSV format
        System.out.println("=== CSV Format ===");
        System.out.println("Name,Department,Salary");
        for (String[] emp : employees) {
            System.out.println(String.join(",", emp));
        }
        
        // Convert to table format
        System.out.println("\n=== Table Format ===");
        System.out.printf("%-10s %-15s %-10s%n", "Name", "Department", "Salary");
        System.out.println("-".repeat(35));
        for (String[] emp : employees) {
            System.out.printf("%-10s %-15s $%-9s%n", emp[0], emp[1], emp[2]);
        }
        
        // Convert to simple JSON-style format
        System.out.println("\n=== JSON-Style Format ===");
        System.out.println("[");
        for (int i = 0; i < employees.length; i++) {
            String comma = (i < employees.length - 1) ? "," : "";
            System.out.println("  { \"name\": \"" + employees[i][0] + 
                "\", \"dept\": \"" + employees[i][1] + 
                "\", \"salary\": " + employees[i][2] + " }" + comma);
        }
        System.out.println("]");
    }
}

Output

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Edit the code on the left, then click Run

Java|39 lines|1479 chars|✓ Valid syntax

UTF-8

Quick Quiz: Data Formats

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Serialization & Data Formats

35 min•By Priygop Team•Last updated: Feb 2026

Working with CSV Data

Example

import java.util.*;

public class CSVProcessor {
    // Parse CSV line (simple implementation)
    static String[] parseCSV(String line) {
        return line.split(",");
    }
    
    // Format as CSV
    static String toCSV(String[] fields) {
        return String.join(",", fields);
    }
    
    public static void main(String[] args) {
        // Sample CSV data
        String[] csvData = {
            "Name,Department,Salary",
            "Alice,Engineering,85000",
            "Bob,Marketing,72000",
            "Charlie,Engineering,92000",
            "Diana,HR,68000",
            "Eve,Engineering,88000"
        };
        
        // Parse and display
        System.out.println("=== Employee Data ===");
        String[] headers = parseCSV(csvData[0]);
        
        double totalSalary = 0;
        int empCount = 0;
        
        for (int i = 1; i < csvData.length; i++) {
            String[] fields = parseCSV(csvData[i]);
            System.out.println(fields[0] + " | " + fields[1] + " | $" + fields[2]);
            totalSalary += Double.parseDouble(fields[2]);
            empCount++;
        }
        
        System.out.println("\nTotal employees: " + empCount);
        System.out.println("Average salary: $" + String.format("%.0f", totalSalary / empCount));
        
        // Filter by department
        String targetDept = "Engineering";
        System.out.println("\n" + targetDept + " team:");
        for (int i = 1; i < csvData.length; i++) {
            String[] fields = parseCSV(csvData[i]);
            if (fields[1].equals(targetDept)) {
                System.out.println("  " + fields[0] + ": $" + fields[2]);
            }
        }
    }
}

Try It Yourself: Data Transformer

Try It Yourself: Data TransformerJava

Java Editor

✓ ValidTab = 2 spaces

import java.util.*;

public class DataTransformer {
    public static void main(String[] args) {
        // Transform between data formats
        String[][] employees = {
            {"Alice", "Engineering", "85000"},
            {"Bob", "Marketing", "72000"},
            {"Charlie", "Engineering", "92000"},
            {"Diana", "HR", "68000"},
        };
        
        // Convert to CSV format
        System.out.println("=== CSV Format ===");
        System.out.println("Name,Department,Salary");
        for (String[] emp : employees) {
            System.out.println(String.join(",", emp));
        }
        
        // Convert to table format
        System.out.println("\n=== Table Format ===");
        System.out.printf("%-10s %-15s %-10s%n", "Name", "Department", "Salary");
        System.out.println("-".repeat(35));
        for (String[] emp : employees) {
            System.out.printf("%-10s %-15s $%-9s%n", emp[0], emp[1], emp[2]);
        }
        
        // Convert to simple JSON-style format
        System.out.println("\n=== JSON-Style Format ===");
        System.out.println("[");
        for (int i = 0; i < employees.length; i++) {
            String comma = (i < employees.length - 1) ? "," : "";
            System.out.println("  { \"name\": \"" + employees[i][0] + 
                "\", \"dept\": \"" + employees[i][1] + 
                "\", \"salary\": " + employees[i][2] + " }" + comma);
        }
        System.out.println("]");
    }
}

import java.util.*;

Output

Click ▶ Run to see the result

Edit the code on the left, then click Run

Java|39 lines|1479 chars|✓ Valid syntax

UTF-8

Serialization & Data Formats

Working with CSV Data

Try It Yourself: Data Transformer

Quick Quiz: Data Formats

Topics in This Module

Serialization & Data Formats

Working with CSV Data

Try It Yourself: Data Transformer

Quick Quiz: Data Formats

Topics in This Module