### Question:
XYSeriesCollection extends AbstractIntervalXYDataset implements IntervalXYDataset, DomainInfo, RangeInfo, 
        VetoableChangeListener, PublicCloneable, Serializable { @Override public boolean equals(Object obj) { if (obj == this) { return true; } if (!(obj instanceof XYSeriesCollection)) { return false; } XYSeriesCollection that = (XYSeriesCollection) obj; if (!this.intervalDelegate.equals(that.intervalDelegate)) { return false; } return ObjectUtils.equal(this.data, that.data); } XYSeriesCollection();  XYSeriesCollection(XYSeries series); @Override DomainOrder getDomainOrder(); void addSeries(XYSeries series); void removeSeries(int series); void removeSeries(XYSeries series); void removeAllSeries(); @Override int getSeriesCount(); List<XYSeries> getSeries(); int indexOf(XYSeries series); XYSeries getSeries(int series); XYSeries getSeries(Comparable key); @Override Comparable getSeriesKey(int series); int getSeriesIndex(Comparable key); @Override int getItemCount(int series); @Override Number getX(int series, int item); @Override Number getStartX(int series, int item); @Override Number getEndX(int series, int item); @Override Number getY(int series, int index); @Override Number getStartY(int series, int item); @Override Number getEndY(int series, int item); @Override boolean equals(Object obj); @Override Object clone(); @Override int hashCode(); @Override double getDomainLowerBound(boolean includeInterval); @Override double getDomainUpperBound(boolean includeInterval); @Override Range getDomainBounds(boolean includeInterval); double getIntervalWidth(); void setIntervalWidth(double width); double getIntervalPositionFactor(); void setIntervalPositionFactor(double factor); boolean isAutoWidth(); void setAutoWidth(boolean b); @Override Range getRangeBounds(boolean includeInterval); @Override double getRangeLowerBound(boolean includeInterval); @Override double getRangeUpperBound(boolean includeInterval); @Override void vetoableChange(PropertyChangeEvent e);  }### Answer:
@Test public void testEquals() { XYSeries s1 = new XYSeries("Series"); s1.add(1.0, 1.1); XYSeriesCollection c1 = new XYSeriesCollection(); c1.addSeries(s1); XYSeries s2 = new XYSeries("Series"); s2.add(1.0, 1.1); XYSeriesCollection c2 = new XYSeriesCollection(); c2.addSeries(s2); assertEquals(c1, c2); assertEquals(c2, c1); c1.addSeries(new XYSeries("Empty Series")); assertFalse(c1.equals(c2)); c2.addSeries(new XYSeries("Empty Series")); assertEquals(c1, c2); c1.setIntervalWidth(5.0); assertFalse(c1.equals(c2)); c2.setIntervalWidth(5.0); assertEquals(c1, c2); c1.setIntervalPositionFactor(0.75); assertFalse(c1.equals(c2)); c2.setIntervalPositionFactor(0.75); assertEquals(c1, c2); c1.setAutoWidth(true); assertFalse(c1.equals(c2)); c2.setAutoWidth(true); assertEquals(c1, c2); }