JDBC (Java Database Connectivity) is a Java API used to connect a Java application with a PostgreSQL Database and execute SQL statements. In the non-Maven approach, we manually download the PostgreSQL JDBC driver JAR and include it in the classpath while compiling and running the Java program. The PostgreSQL JDBC driver is commonly known as pgJDBC. It allows Java applications to communicate with PostgreSQL databases through the standard JDBC API.

Step 1: Install and Start PostgreSQL Database

Make sure PostgreSQL Database Server is installed and running.

Example connection details:

Host     : localhost
Port     : 5432
Database : jdbc_demo
Username : postgres
Password : password

Replace password with the actual password configured for your PostgreSQL user.

The default PostgreSQL port is:

5432

Step 2: Download the PostgreSQL JDBC Driver

Go to the official PostgreSQL JDBC driver website:

PostgreSQL JDBC Driver – Official Website

Download the PostgreSQL JDBC driver JAR.

The downloaded file will have a name similar to:

postgresql-42.x.x.jar

The exact version may differ depending on the current PostgreSQL JDBC driver release.

For this example, assume:

postgresql-42.x.x.jar

Step 3: Create the Project Folder Structure

Create the following folders:

PostgreSQLJDBC/
│
├── postgresql-42.x.x.jar
│
├── StudentApp.java

Step 4: Create the Database Table

Before running the Java program, create a database in PostgreSQL.

CREATE DATABASE jdbc_demo;

Connect to the database:
\c jdbc_demo

Create the student table:
CREATE TABLE student (
    id INTEGER PRIMARY KEY,
    name VARCHAR(50)
);

Insert sample data:
INSERT INTO student VALUES (1, 'Raja');
INSERT INTO student VALUES (2, 'Ram');Code language: JavaScript (javascript)

Step 5: Write the JDBC Program

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class StudentApp {

    public static void main(String[] args) {

        try {

            // Load PostgreSQL JDBC Driver
            Class.forName("org.postgresql.Driver");

            // Create Connection
            Connection con = DriverManager.getConnection(
                "jdbc:postgresql://localhost:5432/jdbc_demo",
                "postgres",
                "password"
            );

            // Create Statement
            Statement st = con.createStatement();

            // Execute Query
            ResultSet rs = st.executeQuery(
                "SELECT * FROM student"
            );

            // Display Results
            while (rs.next()) {

                System.out.println(
                    rs.getInt("id") + " " +
                    rs.getString("name")
                );
            }

            // Close Resources
            rs.close();
            st.close();
            con.close();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Step 6: Open Command Prompt or PowerShell

Navigate to the project folder.

For example:

cd D:\PostgreSQLJDBC

Step 7: Compile Using the Classpath

Compile the Java program:

javac -classpath “.;D:\PostgreSQLJDBC\postgresql.jar” StudentApp.java

Run the program using:

java -classpath “.;D:\PostgreSQLJDBC\postgresql.jar” StudentApp

Execution and Output:

PS D:\PostgreSQLJDBC> javac -classpath ".;D:\PostgreSQLJDBC\postgresql.jar" StudentApp.java
PS D:\PostgreSQLJDBC> java -classpath ".;D:\PostgreSQLJDBC\postgresql.jar" StudentApp
1 Raja
2 RamCode language: CSS (css)