import java.util.Vector;
 
public class Author{
 
/** Name of the Author */
private String name;
 
 
/**
 * Constructor.
 * @param name Name of the author
 */
public Author(String name) {
	this.name = name;
}
 
/**
 * Gets the name of the Author
 * @return Name of the author
 */
public String getName() {
	return this.name;
}
 
 
}

public class Main1 {
 
/**
 * Entry point.
 * @param args Command-line arguments
 */
public static void main(String args[]) {
    Material m1 = new Material("Object Oriented Programming. Java practices");
    Material m2 = new Material("UML cases");
    Material m3 = new Material("Introduction to Programming");
    Material m4 = new Material("Algebra Theory");
    Material m5 = new Material("Graph Theory");
    Author a1 = new Author("John Pitt");
    Author a2 = new Author("Ella Stallone");
    Author a3 = new Author("Josh MacQueen");
    Author a4 = new Author("Peter Hoffmann");
    Author a5 = new Author("Stella Clooney");
    Author a6 = new Author("George Damon");
    Author a7 = new Author("Sarah Burton");
 
    // ADD AUTHOR a1 TO MATERIAL m1
    m1.addAuthor(a1);
    // ADD AUTHOR a5 TO MATERIAL m1
    m1.addAuthor(a5);
    // ADD AUTHOR a6 TO MATERIAL m1
    m1.addAuthor(a6);
    // a5 is already author of m1, it should not be added again
    m1.addAuthor(a5);
    m2.addAuthor(a1);
    m3.addAuthor(a2);
    m3.addAuthor(a7);
    m4.addAuthor(a2);
    m4.addAuthor(a4);
    m4.addAuthor(a3);
    // Try to add 1 more author than the maximum number of authors a material can have
    m4.addAuthor(a1);

public class Material extends Author { 		
 
/** Maximum number of Authors in any Material */
private static final int MAX_AUTHORS = 3;
 
/** Material Authors */
private Author[] authors;
 
/** Authors number */
private int authorsN;
 
/** Materials Title */
private String title;
 
/**
 * Constructor.
 * @param title The title of this material
 */
public Material(String title) {
	super(name);
	this.title = title;
	this.authorsN = 0;
}

public class Material extends Author { 	
 
/** Maximum number of Authors in any Material */
private static final int MAX_AUTHORS = 3;
 
/** Material Authors */
private Author[] authors;
 
/** Authors number */
private int authorsN;
 
/** Materials Title */
private String title;
 
/**
 * Constructor.
 * @param title The title of this material
 */
public Material(String title) { //si lo dejo asi, el compilador me dice que debo hacer modificaciones en la clase Author. Si en vez de (String title) anado (String title, String name) me aparece problema de compilado en la clase main. 
	super(name); //si en vez de name escribo title el programa me compila bien
	this.title = title;
	this.authorsN = 0;
}

public static void main(String args[]) {
    Material m1 = new Material("Object Oriented Programming. Java practices");
    Material m2 = new Material("UML cases");
    Material m3 = new Material("Introduction to Programming");
    Material m4 = new Material("Algebra Theory");
    Material m5 = new Material("Graph Theory");
}

public Material(String title) { 
	super(name);

//private String name; original
protected static String name; //lo que debo modificar segun el compilador

public void sort() {
 		boolean end = false;		//SINTACTIC ERROR: we must write boolean and not bool
		int upperLimit = this.quantity - 1;
		while ((upperLimit > 0) && (!end)) {
			boolean swapped = false;
			for (int j = 0; j < upperLimit; j++) {
				if (!isSorted(j, j+1))
					swap(j, j + 1);
					swapped = true;
				}
			}
			if (!swapped) {     //aquí es donde me falla
				end = true;
			}
			upperLimit++;
		};