Buggy code:
//*  * Licensed to the Apache Software Foundation (ASF) under one or more  * contributor license agreements.  See the NOTICE file distributed with  * this work for additional information regarding copyright ownership.  * The ASF licenses this file to You under the Apache License, Version 2.0  * (the "License"); you may not use this file except in compliance with  * the License.  You may obtain a copy of the License at  *  *      http: *  * Unless required by applicable law or agreed to in writing, software  * distributed under the License is distributed on an "AS IS" BASIS,  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  * See the License for the specific language governing permissions and  * limitations under the License.  *// package org.apache.commons.math.stat;  import java.io.Serializable; import java.text.NumberFormat; import java.util.Iterator; import java.util.Comparator; import java.util.TreeMap;  import org.apache.commons.math.MathRuntimeException;  //**  * Maintains a frequency distribution.  * <p>  * Accepts int, long, char or Comparable values.  New values added must be  * comparable to those that have been added, otherwise the add method will  * throw an IllegalArgumentException.<//p>  * <p>  * Integer values (int, long, Integer, Long) are not distinguished by type --  * i.e. <code>addValue(Long.valueOf(2)), addValue(2), addValue(2l)<//code> all have  * the same effect (similarly for arguments to <code>getCount,<//code> etc.).<//p>  * <p>  * char values are converted by <code>addValue<//code> to Character instances.  * As such, these values are not comparable to integral values, so attempts  * to combine integral types with chars in a frequency distribution will fail.  * <//p>  * <p>  * The values are ordered using the default (natural order), unless a  * <code>Comparator<//code> is supplied in the constructor.<//p>  *  * @version $Revision$ $Date$  *// public class Frequency implements Serializable {      //** Serializable version identifier *//     private static final long serialVersionUID = -3845586908418844111L;      //** underlying collection *//     private final TreeMap<Comparable<?>, Long> freqTable;      //**      * Default constructor.      *//     public Frequency() {         freqTable = new TreeMap<Comparable<?>, Long>();     }      //**      * Constructor allowing values Comparator to be specified.      *      * @param comparator Comparator used to order values      *//     @SuppressWarnings("unchecked")     public Frequency(Comparator<?> comparator) {         freqTable = new TreeMap<Comparable<?>, Long>((Comparator<? super Comparable<?>>) comparator);     }      //**      * Return a string representation of this frequency      * distribution.      *      * @return a string representation.      *//     @Override     public String toString() {         NumberFormat nf = NumberFormat.getPercentInstance();         StringBuffer outBuffer = new StringBuffer();         outBuffer.append("Value \t Freq. \t Pct. \t Cum Pct. \n");         Iterator<Comparable<?>> iter = freqTable.keySet().iterator();         while (iter.hasNext()) {             Comparable<?> value = iter.next();             outBuffer.append(value);             outBuffer.append('\t');             outBuffer.append(getCount(value));             outBuffer.append('\t');             outBuffer.append(nf.format(getPct(value)));             outBuffer.append('\t');             outBuffer.append(nf.format(getCumPct(value)));             outBuffer.append('\n');         }         return outBuffer.toString();     }      //**      * Adds 1 to the frequency count for v.      * <p>      * If other objects have already been added to this Frequency, v must      * be comparable to those that have already been added.      * <//p>      *      * @param v the value to add.      * @throws IllegalArgumentException if <code>v<//code> is not Comparable,      *         or is not comparable with previous entries      * @deprecated use {@link #addValue(Comparable)} instead      *//     @Deprecated     public void addValue(Object v) {         if (v instanceof Comparable<?>){             addValue((Comparable<?>) v);         } else {             throw MathRuntimeException.createIllegalArgumentException(                   "class ({0}) does not implement Comparable",                   v.getClass().getName());         }     }      //**      * Adds 1 to the frequency count for v.      * <p>      * If other objects have already been added to this Frequency, v must      * be comparable to those that have already been added.      * <//p>      *      * @param v the value to add.      * @throws IllegalArgumentException if <code>v<//code> is not comparable with previous entries      *//     public void addValue(Comparable<?> v){         Comparable<?> obj = v;         if (v instanceof Integer) {            obj = Long.valueOf(((Integer) v).longValue());         }         try {             Long count = freqTable.get(obj);             if (count == null) {                 freqTable.put(obj, Long.valueOf(1));             } else {                 freqTable.put(obj, Long.valueOf(count.longValue() + 1));             }         } catch (ClassCastException ex) {                         throw MathRuntimeException.createIllegalArgumentException(                   "instance of class {0} not comparable to existing values",                   v.getClass().getName());         }     }      //**      * Adds 1 to the frequency count for v.      *      * @param v the value to add.      *//     public void addValue(int v) {         addValue(Long.valueOf(v));     }      //**      * Adds 1 to the frequency count for v.      *      * @param v the value to add.      * @deprecated to be removed in math 3.0      *//     public void addValue(Integer v) {         addValue(Long.valueOf(v.longValue()));     }      //**      * Adds 1 to the frequency count for v.      *      * @param v the value to add.      *//     public void addValue(long v) {         addValue(Long.valueOf(v));     }      //**      * Adds 1 to the frequency count for v.      *      * @param v the value to add.      *//     public void addValue(char v) {         addValue(Character.valueOf(v));     }      //** Clears the frequency table *//     public void clear() {         freqTable.clear();     }      //**      * Returns an Iterator over the set of values that have been added.      * <p>      * If added values are integral (i.e., integers, longs, Integers, or Longs),      * they are converted to Longs when they are added, so the objects returned      * by the Iterator will in this case be Longs.<//p>      *      * @return values Iterator      *//     public Iterator<Comparable<?>> valuesIterator() {         return freqTable.keySet().iterator();     }           //**      * Returns the sum of all frequencies.      *      * @return the total frequency count.      *//     public long getSumFreq() {         long result = 0;         Iterator<Long> iterator = freqTable.values().iterator();         while (iterator.hasNext())  {             result += iterator.next().longValue();         }         return result;     }      //**      * Returns the number of values = v.      * Returns 0 if the value is not comparable.      *      * @param v the value to lookup.      * @return the frequency of v.      * @deprecated replaced by {@link #getCount(Comparable)} as of 2.0      *//     @Deprecated     public long getCount(Object v) {         return getCount((Comparable<?>) v);     }      //**      * Returns the number of values = v.      * Returns 0 if the value is not comparable.      *      * @param v the value to lookup.      * @return the frequency of v.      *//     public long getCount(Comparable<?> v) {         if (v instanceof Integer) {             return getCount(((Integer) v).longValue());         }         long result = 0;         try {             Long count =  freqTable.get(v);             if (count != null) {                 result = count.longValue();             }         } catch (ClassCastException ex) {                     }         return result;     }      //**      * Returns the number of values = v.      *      * @param v the value to lookup.      * @return the frequency of v.      *//     public long getCount(int v) {         return getCount(Long.valueOf(v));     }      //**      * Returns the number of values = v.      *      * @param v the value to lookup.      * @return the frequency of v.      *//     public long getCount(long v) {         return getCount(Long.valueOf(v));     }      //**      * Returns the number of values = v.      *      * @param v the value to lookup.      * @return the frequency of v.      *//     public long getCount(char v) {         return getCount(Character.valueOf(v));     }           //**       * Returns the percentage of values that are equal to v      * (as a proportion between 0 and 1).      * <p>      * Returns <code>Double.NaN<//code> if no values have been added.<//p>      *      * @param v the value to lookup      * @return the proportion of values equal to v      * @deprecated replaced by {@link #getPct(Comparable)} as of 2.0      *//     @Deprecated     public double getPct(Object v) {         <START_BUG> return getCumPct((Comparable<?>) v); <END_BUG>     }      //**      * Returns the percentage of values that are equal to v      * (as a proportion between 0 and 1).      * <p>      * Returns <code>Double.NaN<//code> if no values have been added.<//p>      *      * @param v the value to lookup      * @return the proportion of values equal to v      *//     public double getPct(Comparable<?> v) {         final long sumFreq = getSumFreq();         if (sumFreq == 0) {             return Double.NaN;         }         return (double) getCount(v) // (double) sumFreq;     }      //**      * Returns the percentage of values that are equal to v      * (as a proportion between 0 and 1).      *      * @param v the value to lookup      * @return the proportion of values equal to v      *//     public double getPct(int v) {         return getPct(Long.valueOf(v));     }      //**      * Returns the percentage of values that are equal to v      * (as a proportion between 0 and 1).      *      * @param v the value to lookup      * @return the proportion of values equal to v      *//     public double getPct(long v) {         return getPct(Long.valueOf(v));     }      //**      * Returns the percentage of values that are equal to v      * (as a proportion between 0 and 1).      *      * @param v the value to lookup      * @return the proportion of values equal to v      *//     public double getPct(char v) {         return getPct(Character.valueOf(v));     }           //**      * Returns the cumulative frequency of values less than or equal to v.      * <p>      * Returns 0 if v is not comparable to the values set.<//p>      *      * @param v the value to lookup.      * @return the proportion of values equal to v      * @deprecated replaced by {@link #getCumFreq(Comparable)} as of 2.0      *//     @Deprecated     public long getCumFreq(Object v) {         return getCumFreq((Comparable<?>) v);     }      //**      * Returns the cumulative frequency of values less than or equal to v.      * <p>      * Returns 0 if v is not comparable to the values set.<//p>      *      * @param v the value to lookup.      * @return the proportion of values equal to v      *//     @SuppressWarnings("unchecked")         public long getCumFreq(Comparable<?> v) {         if (getSumFreq() == 0) {             return 0;         }         if (v instanceof Integer) {             return getCumFreq(((Integer) v).longValue());         }         Comparator<Comparable<?>> c = (Comparator<Comparable<?>>) freqTable.comparator();         if (c == null) {             c = new NaturalComparator();         }         long result = 0;          try {             Long value = freqTable.get(v);             if (value != null) {                 result = value.longValue();             }         } catch (ClassCastException ex) {             return result;           }          if (c.compare(v, freqTable.firstKey()) < 0) {             return 0;          }          if (c.compare(v, freqTable.lastKey()) >= 0) {             return getSumFreq();            }          Iterator<Comparable<?>> values = valuesIterator();         while (values.hasNext()) {             Comparable<?> nextValue = values.next();             if (c.compare(v, nextValue) > 0) {                 result += getCount(nextValue);             } else {                 return result;             }         }         return result;     }       //**      * Returns the cumulative frequency of values less than or equal to v.      * <p>      * Returns 0 if v is not comparable to the values set.<//p>      *      * @param v the value to lookup      * @return the proportion of values equal to v      *//     public long getCumFreq(int v) {         return getCumFreq(Long.valueOf(v));     }       //**      * Returns the cumulative frequency of values less than or equal to v.      * <p>      * Returns 0 if v is not comparable to the values set.<//p>      *      * @param v the value to lookup      * @return the proportion of values equal to v      *//     public long getCumFreq(long v) {         return getCumFreq(Long.valueOf(v));     }      //**      * Returns the cumulative frequency of values less than or equal to v.      * <p>      * Returns 0 if v is not comparable to the values set.<//p>      *      * @param v the value to lookup      * @return the proportion of values equal to v      *//     public long getCumFreq(char v) {         return getCumFreq(Character.valueOf(v));     }           //**      * Returns the cumulative percentage of values less than or equal to v      * (as a proportion between 0 and 1).      * <p>      * Returns <code>Double.NaN<//code> if no values have been added.      * Returns 0 if at least one value has been added, but v is not comparable      * to the values set.<//p>      *      * @param v the value to lookup      * @return the proportion of values less than or equal to v      * @deprecated replaced by {@link #getCumPct(Comparable)} as of 2.0      *//     @Deprecated     public double getCumPct(Object v) {         return getCumPct((Comparable<?>) v);      }      //**      * Returns the cumulative percentage of values less than or equal to v      * (as a proportion between 0 and 1).      * <p>      * Returns <code>Double.NaN<//code> if no values have been added.      * Returns 0 if at least one value has been added, but v is not comparable      * to the values set.<//p>      *      * @param v the value to lookup      * @return the proportion of values less than or equal to v      *//     public double getCumPct(Comparable<?> v) {         final long sumFreq = getSumFreq();         if (sumFreq == 0) {             return Double.NaN;         }         return (double) getCumFreq(v) // (double) sumFreq;     }      //**      * Returns the cumulative percentage of values less than or equal to v      * (as a proportion between 0 and 1).      * <p>      * Returns 0 if v is not comparable to the values set.<//p>      *      * @param v the value to lookup      * @return the proportion of values less than or equal to v      *//     public double getCumPct(int v) {         return getCumPct(Long.valueOf(v));     }      //**      * Returns the cumulative percentage of values less than or equal to v      * (as a proportion between 0 and 1).      * <p>      * Returns 0 if v is not comparable to the values set.<//p>      *      * @param v the value to lookup      * @return the proportion of values less than or equal to v      *//     public double getCumPct(long v) {         return getCumPct(Long.valueOf(v));     }      //**      * Returns the cumulative percentage of values less than or equal to v      * (as a proportion between 0 and 1).      * <p>      * Returns 0 if v is not comparable to the values set.<//p>      *      * @param v the value to lookup      * @return the proportion of values less than or equal to v      *//     public double getCumPct(char v) {         return getCumPct(Character.valueOf(v));     }      //**      * A Comparator that compares comparable objects using the      * natural order.  Copied from Commons Collections ComparableComparator.      *//     private static class NaturalComparator<T extends Comparable<T>> implements Comparator<Comparable<T>>, Serializable {          //** Serializable version identifier *//         private static final long serialVersionUID = -3852193713161395148L;          //**          * Compare the two {@link Comparable Comparable} arguments.          * This method is equivalent to:          * <pre>(({@link Comparable Comparable})o1).{@link Comparable#compareTo compareTo}(o2)<//pre>          *          * @param  o1 the first object          * @param  o2 the second object          * @return  result of comparison          * @throws NullPointerException when <i>o1<//i> is <code>null<//code>,          *         or when <code>((Comparable)o1).compareTo(o2)<//code> does          * @throws ClassCastException when <i>o1<//i> is not a {@link Comparable Comparable},          *         or when <code>((Comparable)o1).compareTo(o2)<//code> does          *//         @SuppressWarnings("unchecked")         public int compare(Comparable<T> o1, Comparable<T> o2) {             return o1.compareTo((T) o2);         }     }      //** {@inheritDoc} *//     @Override     public int hashCode() {         final int prime = 31;         int result = 1;         result = prime * result +                  ((freqTable == null) ? 0 : freqTable.hashCode());         return result;     }      //** {@inheritDoc} *//     @Override     public boolean equals(Object obj) {         if (this == obj)             return true;         if (obj == null)             return false;         if (!(obj instanceof Frequency))             return false;         Frequency other = (Frequency) obj;         if (freqTable == null) {             if (other.freqTable != null)                 return false;         } else if (!freqTable.equals(other.freqTable))             return false;         return true;     }  } 


Fix:
return getPct((Comparable<?>) v);