Tree.java

public class Tree {
    /*
     * Usually, you would use an array for this, but I wanted to keep it simple.
     */

    /** A leaf of this tree */
    Leaf leaf1;

    /** Theoretically, you should make those comments over every line */
    Leaf leaf2;
    Leaf leaf3;
    Leaf leaf4;
    Root mainRoot;

    /** age in years */
    int age;

    /** name of this tree in English */
    String name;

    /** scientific name of this type of tree in Latin */
    String scientificName;

}