Here's the answer: 

class Locker {
  boolean open;
  int counter;
  Locker() {

  }
  public String toString() {
    return this.open ? "*" : " ";
  }
  void flip() {
    this.counter += 1;
    this.open = ! this.open;
    // System.out.println(this.counter + ": " + ( this.open ? "open" : "closed"));
  }
  public static void main(String[] args) {
    Locker[] lockers = new Locker[100];
    for (int i = 0; i < lockers.length; i++)
      lockers[i] = new Locker();
    for (int student = 1; student <= 100; student++) {
      for (int locker = student - 1; locker < lockers.length; locker += student )
        lockers[locker].flip();
      for (int i = 0; i < lockers.length; i++)
        System.out.print(lockers[i]);
      System.out.println();
    }
  }
}

-bash-4.1$ java Locker
****************************************************************************************************
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*   ***   ***   ***   ***   ***   ***   ***   ***   ***   ***   ***   ***   ***   ***   ***   ***
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*  * *** ** * *****   *    ** **    *   ***** * ** *** *  ***  * *** ** * *****   *    ** **    *
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*  *    ******* *** * *   * ***   * *  *****  *  * *** *  * *     **  *** **  *** *     *  *    ***
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*  *    *      * ******* ************ * * * * *   * ***   ***  ****   * *  ****** * *  ** **    *  *
*  *    *      *  ****** ********** * * * * * *   * * *   ***  ****   ***  ****** * *  *****    *  *
*  *    *      *   ***** ********** *** * * * *   * * * * ***  ****   ***   ***** * *  *****  * *  *
*  *    *      *    **** ********** ***** * * *   * * * * * *  ****   ***   *** * * *  *****  * *
*  *    *      *     *** ********** ******* * *   * * * * * * *****   ***   *** * ***  *****  * *
*  *    *      *      ** ********** ********* *   * * * * * * *** *   ***   *** * ***   ****  * *
*  *    *      *       * ********** ***********   * * * * * * *** * * ***   *** * ***   ***   * *
*  *    *      *         ********** ************  * * * * * * *** * * * *   *** * ***   ***   ***
*  *    *      *        *********** ************ ** * * * * * *** * * * * * *** * ***   ***   ***  *
*  *    *      *        * ********* ************ **** * * * * *** * * * * * * * * ***   ***   ***  *
*  *    *      *        *  ******** ************ ****** * * * *** * * * * * * *   ***   ***   ***  *
*  *    *      *        *   ******* ************ ******** * * *** * * * * * * *   * *   ***   ***  *
*  *    *      *        *    ****** ************ ********** * *** * * * * * * *   * * * ***   ***  *
*  *    *      *        *     ***** ************ ************ *** * * * * * * *   * * * * *   ***  *
*  *    *      *        *      **** ************ **************** * * * * * * *   * * * * * * ***  *
*  *    *      *        *       *** ************ ************** * * * * * * * *   * * * * * * * *  *
*  *    *      *        *        ** ************ ************** *** * * * * * *   * * * * * * * * **
*  *    *      *        *         * ************ ************** ***** * * * * *   * * * * * * * * **
*  *    *      *        *           ************ ************** ******* * * * *   * * * * * * * * **
*  *    *      *        *          ************* ************** ********* * * *   * * * * * * * * **
*  *    *      *        *          * *********** ************** *********** * *   * * * * * * * * **
*  *    *      *        *          *  ********** ************** ************* *   * * * * * * * * **
*  *    *      *        *          *   ********* ************** ***************   * * * * * * * * **
*  *    *      *        *          *    ******** ************** ****************  * * * * * * * * **
*  *    *      *        *          *     ******* ************** **************** ** * * * * * * * **
*  *    *      *        *          *      ****** ************** **************** **** * * * * * * **
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*  *    *      *        *          *        **** ************** **************** ******** * * * * **
*  *    *      *        *          *         *** ************** **************** ********** * * * **
*  *    *      *        *          *          ** ************** **************** ************ * * **
*  *    *      *        *          *           * ************** **************** ************** * **
*  *    *      *        *          *             ************** **************** **************** **
*  *    *      *        *          *            *************** **************** *******************
*  *    *      *        *          *            * ************* **************** ******************
*  *    *      *        *          *            *  ************ **************** ******************
*  *    *      *        *          *            *   *********** **************** ******************
*  *    *      *        *          *            *    ********** **************** ******************
*  *    *      *        *          *            *     ********* **************** ******************
*  *    *      *        *          *            *      ******** **************** ******************
*  *    *      *        *          *            *       ******* **************** ******************
*  *    *      *        *          *            *        ****** **************** ******************
*  *    *      *        *          *            *         ***** **************** ******************
*  *    *      *        *          *            *          **** **************** ******************
*  *    *      *        *          *            *           *** **************** ******************
*  *    *      *        *          *            *            ** **************** ******************
*  *    *      *        *          *            *             * **************** ******************
*  *    *      *        *          *            *               **************** ******************
*  *    *      *        *          *            *              ***************** ******************
*  *    *      *        *          *            *              * *************** ******************
*  *    *      *        *          *            *              *  ************** ******************
*  *    *      *        *          *            *              *   ************* ******************
*  *    *      *        *          *            *              *    ************ ******************
*  *    *      *        *          *            *              *     *********** ******************
*  *    *      *        *          *            *              *      ********** ******************
*  *    *      *        *          *            *              *       ********* ******************
*  *    *      *        *          *            *              *        ******** ******************
*  *    *      *        *          *            *              *         ******* ******************
*  *    *      *        *          *            *              *          ****** ******************
*  *    *      *        *          *            *              *           ***** ******************
*  *    *      *        *          *            *              *            **** ******************
*  *    *      *        *          *            *              *             *** ******************
*  *    *      *        *          *            *              *              ** ******************
*  *    *      *        *          *            *              *               * ******************
*  *    *      *        *          *            *              *                 ******************
*  *    *      *        *          *            *              *                *******************
*  *    *      *        *          *            *              *                * *****************
*  *    *      *        *          *            *              *                *  ****************
*  *    *      *        *          *            *              *                *   ***************
*  *    *      *        *          *            *              *                *    **************
*  *    *      *        *          *            *              *                *     *************
*  *    *      *        *          *            *              *                *      ************
*  *    *      *        *          *            *              *                *       ***********
*  *    *      *        *          *            *              *                *        **********
*  *    *      *        *          *            *              *                *         *********
*  *    *      *        *          *            *              *                *          ********
*  *    *      *        *          *            *              *                *           *******
*  *    *      *        *          *            *              *                *            ******
*  *    *      *        *          *            *              *                *             *****
*  *    *      *        *          *            *              *                *              ****
*  *    *      *        *          *            *              *                *               ***
*  *    *      *        *          *            *              *                *                **
*  *    *      *        *          *            *              *                *                 *
*  *    *      *        *          *            *              *                *
*  *    *      *        *          *            *              *                *                  *
-bash-4.1$