OK, then... Here we go.

You can use the following source code to blink your first LED on your RPi using Java. In the code you can see that I'm not using any complicated gpio libraries like wiringpi or pi4j, and I'm not doing any low-level pin manipulation like you can in C. And, I'm not using python (hell no!). This is Java programming, so we keep it simple (and more readable) than those other programming languages.

See: Write Java code to do this

import java.io.*

/*
 * Java Embedded Raspberry Pi GPIO app
 */
package jerpigpio;

import java.io.FileWriter;

/**
 *
 * @author hinkmond
 */
public class JerpiGPIO {
    
    static final String GPIO_OUT = "out";
    static final String GPIO_ON = "1";
    static final String GPIO_OFF = "0";
    static final String GPIO_CH00="0";

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        FileWriter commandFile;
        
        try {
            
            /*** Init GPIO port for output ***/
            
            // Open file handles to GPIO port unexport and export controls
            FileWriter unexportFile = new FileWriter("/sys/class/gpio/unexport");
            FileWriter exportFile = new FileWriter("/sys/class/gpio/export");

            // Reset the port
            unexportFile.write(GPIO_CH00);
            unexportFile.flush();
            
            // Set the port for use
            exportFile.write(GPIO_CH00);   
            exportFile.flush();

            // Open file handle to port input/output control
            FileWriter directionFile =
                    new FileWriter("/sys/class/gpio/gpio"+GPIO_CH00+"/direction");
            
            // Set port for output
            directionFile.write(GPIO_OUT);
            directionFile.flush();
            
            /*--- Send commands to GPIO port ---*/
            
            // Opne file handle to issue commands to GPIO port
            commandFile = new FileWriter("/sys/class/gpio/gpio"+GPIO_CH00+"/value");
            
            // Loop forever
            while (true) {
                
                // Set GPIO port ON
                commandFile.write(GPIO_ON);
                commandFile.flush();
        
                // Wait for a while
                java.lang.Thread.sleep(200);
        
                // Set GPIO port OFF
                commandFile.write(GPIO_OFF);
                commandFile.flush();
                
                // Wait for a while
                java.lang.Thread.sleep(200);
            }

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