public class Students{
    // Body of the class
}

private class studentIDs{
    // Body of the Class
}

public class Person{
    int age,height,weight;
    public Person(int age, int height, int weight){
        this.age = age;
        this.height = height;
        this.weight = weight;
    }
}

public class Main{
    public static void main(String args[]){
        Person person1 = new Person(18, 67, 120);
    }
}

public class TesterClass
{
   // main method for testing
   public static void main(String[] args)
   {
      Student s1 = new Student("Skyler", "skyler@sky.com", 123456);
      System.out.println("Name:" +  s1.getName() );
      System.out.println("Email:" +  s1.getEmail() );
      System.out.println("ID: " + s1.getId() );
   }
 }
/** Class Student keeps track of name, email, and id of a Student. */
class Student
{
   private String name;
   private String email;
   private int id;

   public Student(String initName, String initEmail, int initId)
   {
      name = initName;
      email = initEmail;
      id = initId;
   }

   // accessor methods - getters
   /** getName()  @return name */
   public String getName()
   {
      return name;
   }
   /** getEmail()  @return email */
   public String getEmail()
   {
      return email;
   }
   /** getName()  @return id */
   public int getId()
   {
      return id;
   }
}

TesterClass.main(null);

import java.util.Arrays;

public class Student {

	private String name;
	private Integer ID;
	private String DOB;
	private double GPA;
	private String[] courses;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Integer getID() {
		return ID;
	}

	public void setID(Integer iD) {
		this.ID = iD;
	}

	public String getDOB() {
		return DOB;
	}

	public void setDOB(String dOB) {
		this.DOB = dOB;
	}

	public double getGPA() {
		return GPA;
	}

	public void setGPA(double gPA) {
		this.GPA = gPA;
	}

	public String[] getCourses() {
		return courses;
	}

	public void setCourses(String[] courses) {
		this.courses = courses;
	}

	public static void main(String[] args) {

		Student student1 = new Student();

		System.out.println("Student Bio [ Before using Accessors & Mutators ]");

		// calling accessor methods
		System.out.print("Name: " + student1.getName());
		System.out.print("\tID: " + student1.getID());
		System.out.print("\tGPA: " + student1.getGPA());
		System.out.print("\tDOB: " + student1.getDOB());
		System.out.println("\tCourses: " +  Arrays.toString(student1.getCourses()));

		// calling mutator methods
		student1.setName("Alex Coy");
		student1.setID(3115);
		student1.setGPA(2.79);
		student1.setDOB("08/08/1998");
		String[] courses = { "Object Oriented Programming", "Cryptography", "Photography", "Network Security" };
		student1.setCourses(courses);

		System.out.println("\nStudent Bio [ After using Mutators & Accessors ]");

		// calling accessor methods
		System.out.print("Name: " + student1.getName());
		System.out.print("\tID: " + student1.getID());
		System.out.print("\tGPA: " + student1.getGPA());
		System.out.print("\tDOB: " + student1.getDOB());
		System.out.println("\tCourses: " + Arrays.toString(student1.getCourses()));
	}
}
Student.main(null);

public abstract class Fibo {
    String name;  // name or title of method
    int size;  // nth sequence
    int hashID;  // counter for hashIDs in hash map
    ArrayList<Long> list;   // captures current Fibonacci sequence
    HashMap<Integer, Object> hash;  // captures each sequence leading to final result

    // Static variables being initialized once for use throughout the entire class

public class Main{
// static method
public static int getTotal(int a, int b) {
    return a + b;
  }
  
  public static void main(String[] args) {
    int x = 3;
    int y = 2;
    System.out.println(getTotal(x,y)); // Prints: 5
  }
}
Main.main(null);

public class Demo{
    public static void main(String args[]){
      Student s1 = new Student();
      s1.showData();
      Student s2 = new Student();
      s2.showData();
      Student.b++;
      s1.showData();
   }
 }
 
 class Student {
 int a; //initialized to zero
 static int b; //initialized to zero only when class is loaded not for each object created.
 
   Student(){
    //Constructor incrementing static variable b
    b++;
   }
 
    public void showData(){
       System.out.println("Value of a = "+a);
       System.out.println("Value of b = "+b);
    }
 //public static void increment(){
 //a++;
 //}
 
 }
 Demo.main(null);

public class Demo {
    public static void main(String args[]){
        System.out.print("Hello world!");
    }
}
Demo.main(null);

public class Adult{
    public void knowAge(){
        System.out.println("You are an adult!");
    }
}
public class Child extends Adult{
    public void knowAge(){
        System.out.println("You are a child!");
    }
}
public class Main{
    public static void main(String args[]){
        Adult person = new Adult();
        person.knowAge();
        Child kid = new Child();
        kid.knowAge();
    }
}
Main.main(null);

// Java Program for Method overloading
// By using Different Types of Arguments 
 
// Class 1
// Helper class
class Helper {
 
    // Method with 2 integer parameters
    static int Multiply(int a, int b)
    {
 
        // Returns product of integer numbers
        return a * b;
    }
 
    // Method 2
    // With same name but with 2 double parameters
    static double Multiply(double a, double b)
    {
 
        // Returns product of double numbers
        return a * b;
    }
}
 
// Class 2
// Main class
class GFG {
 
    // Main driver method
    public static void main(String[] args)
    {
 
        // Calling method by passing
        // input as in arguments
        System.out.println(Helper.Multiply(2, 4));
        System.out.println(Helper.Multiply(5.5, 6.3));
    }
}
GFG.main(null);