java when to make a class code example

Example 1: how to make a class in java

public class Main {
 public static void main (String[] args) {
	System.out.println("Hello World");
 } 
}

Example 2: how to make a class in java

// Public creates avaliability to all classes/files
public class Object {
  // Instance of a variable per each class created
  public int a = 1;
  // Private restricts in local space (within these brackets)
  private int b = 5;
  
  // Defaults as public
  int c = 0;
  
  // Method Examples
  void setB(int B)
  {
  	b = B;
    // No return b/c 'void'
  }
  int getA()
  {
    return b;
    // Return b/c 'int' in front of method
  }
}