set Time is takeing me a long before the day so there is a issue of time management.

[sumantain]

please justify your code of:
//Setting time of the day (8 am here) when notification will be sent every day (default)
calendar.set(Calendar.HOUR_OF_DAY,
Integer.getInteger(hour, 16),
Integer.getInteger(min, 30));

because Calendar has three set methods are

/**
* Sets the given calendar field to the given value. The value is not
* interpreted by this method regardless of the leniency mode.
*
* @param field the given calendar field.
* @param value the value to be set for the given calendar field.
* @throws ArrayIndexOutOfBoundsException if the specified field is out of range
* (field < 0 || field >= FIELD_COUNT).
* in non-lenient mode.
* @see #set(int,int,int)
* @see #set(int,int,int,int,int)
* @see #set(int,int,int,int,int,int)
* @see #get(int)
*/
public void set(int field, int value)
{
// If the fields are partially normalized, calculate all the
// fields before changing any fields.
if (areFieldsSet && !areAllFieldsSet) {
computeFields();
}
internalSet(field, value);
isTimeSet = false;
areFieldsSet = false;
isSet[field] = true;
stamp[field] = nextStamp++;
if (nextStamp == Integer.MAX_VALUE) {
adjustStamp();
}
}

/**
 * Sets the values for the calendar fields <code>YEAR</code>,
 * <code>MONTH</code>, and <code>DAY_OF_MONTH</code>.
 * Previous values of other calendar fields are retained.  If this is not desired,
 * call {@link #clear()} first.
 *
 * @param year the value used to set the <code>YEAR</code> calendar field.
 * @param month the value used to set the <code>MONTH</code> calendar field.
 * Month value is 0-based. e.g., 0 for January.
 * @param date the value used to set the <code>DAY_OF_MONTH</code> calendar field.
 * @see #set(int,int)
 * @see #set(int,int,int,int,int)
 * @see #set(int,int,int,int,int,int)
 */
public final void set(int year, int month, int date)
{
    set(YEAR, year);
    set(MONTH, month);
    set(DATE, date);
}

/**
 * Sets the values for the calendar fields <code>YEAR</code>,
 * <code>MONTH</code>, <code>DAY_OF_MONTH</code>,
 * <code>HOUR_OF_DAY</code>, and <code>MINUTE</code>.
 * Previous values of other fields are retained.  If this is not desired,
 * call {@link #clear()} first.
 *
 * @param year the value used to set the <code>YEAR</code> calendar field.
 * @param month the value used to set the <code>MONTH</code> calendar field.
 * Month value is 0-based. e.g., 0 for January.
 * @param date the value used to set the <code>DAY_OF_MONTH</code> calendar field.
 * @param hourOfDay the value used to set the <code>HOUR_OF_DAY</code> calendar field.
 * @param minute the value used to set the <code>MINUTE</code> calendar field.
 * @see #set(int,int)
 * @see #set(int,int,int)
 * @see #set(int,int,int,int,int,int)
 */
public final void set(int year, int month, int date, int hourOfDay, int minute)
{
    set(YEAR, year);
    set(MONTH, month);
    set(DATE, date);
    set(HOUR_OF_DAY, hourOfDay);
    set(MINUTE, minute);
}

/**
 * Sets the values for the fields <code>YEAR</code>, <code>MONTH</code>,
 * <code>DAY_OF_MONTH</code>, <code>HOUR</code>, <code>MINUTE</code>, and
 * <code>SECOND</code>.
 * Previous values of other fields are retained.  If this is not desired,
 * call {@link #clear()} first.
 *
 * @param year the value used to set the <code>YEAR</code> calendar field.
 * @param month the value used to set the <code>MONTH</code> calendar field.
 * Month value is 0-based. e.g., 0 for January.
 * @param date the value used to set the <code>DAY_OF_MONTH</code> calendar field.
 * @param hourOfDay the value used to set the <code>HOUR_OF_DAY</code> calendar field.
 * @param minute the value used to set the <code>MINUTE</code> calendar field.
 * @param second the value used to set the <code>SECOND</code> calendar field.
 * @see #set(int,int)
 * @see #set(int,int,int)
 * @see #set(int,int,int,int,int)
 */
public final void set(int year, int month, int date, int hourOfDay, int minute,
                      int second)
{
    set(YEAR, year);
    set(MONTH, month);
    set(DATE, date);
    set(HOUR_OF_DAY, hourOfDay);
    set(MINUTE, minute);
    set(SECOND, second);
}