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POJava: Cannot Cast Object to Date in Comparator
 

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  1. POJava: Cannot Cast Object to Date in Comparator
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    <p>I am attempting to sort a collection of Dates in LinkedList myQueue by emptying it into ArrayList myArrayList, sorting it via Comparator, then iterating over the linked list to place each Date back into the myQueue. </p> <p>Everything works fine until I send the Date Objects into My Comparator for some reasin Casting the dates I created into Dates in the Comparator does not work.</p> <p>Here is the Format the Dates are in:</p> <pre><code> Thu Jul 30 00:00:00 JST 1908 </code></pre> <p>Here is the Error:</p> <pre><code> Exception in thread "main" java.lang.ClassCastException: java.util.Date cannot be cast to Date at DateComparator.compare(DateComparator.java:14) at java.util.TimSort.countRunAndMakeAscending(Unknown Source) at java.util.TimSort.sort(Unknown Source) at java.util.TimSort.sort(Unknown Source) at java.util.Arrays.sort(Unknown Source) at java.util.Collections.sort(Unknown Source) at QueueTest.main(QueueTest.java:76) </code></pre> <p>This is Where I place all Objects in myQueue into myArrayList:</p> <pre><code> if (!myQueue.isEmpty()) { //Collections.sort(myQueue, new DateComparator()); Object nextDate; ArrayList myArrayList = new ArrayList(); while(!myQueue.isEmpty()){ nextDate = myQueue.removeFirst(); myArrayList.add(nextDate); } Collections.sort(myArrayList, new DateComparator()); Iterator it=myArrayList.iterator(); while(it.hasNext()){ myQueue.addLast(it.next()); } </code></pre> <p>And this is where the issue is in My Comparator:</p> <pre><code> Date d1 = (Date) a; Date d2 = (Date) b; </code></pre> <p>I just started going to school for Computer Science in Okinawa, got nobody to really talk to about this asides from my dog so any help is appreciated.</p> <p>//EDIT:</p> <p>This is the Date() SuperClass that My professor requires we use in order to create out Date Objects:</p> <pre><code>public class Date { private static int numberDates=0; public static final int VALID_START_YEAR=1584; private int year; private int month; private int day; public Date() { month = 1; day = 1; year = 1970; numberDates++; } public Date(int newMonth, int newDay, int newYear) { month = newMonth; day = newDay; year = newYear; numberDates++; } public Date( Date other) { month = other.month; day = other.day; year = other.year; numberDates++; } public Date( String date) { java.util.StringTokenizer st = new java.util.StringTokenizer(date,"/"); month = Integer.parseInt(st.nextToken()); //extract next token day = Integer.parseInt(st.nextToken()); year = Integer.parseInt(st.nextToken()); numberDates++; } public int getYear() { return year; } public int getMonth() { return month; } public int getDay() { return day; } public String toString() { return(month + "/" + day + "/" + year); } public static int getNumberDates() { return numberDates; } public void increment() { day++; //stub for the actual method to be written later... } public static void clearNumberDates() { numberDates = 0; } public static boolean isValidDay(int month, int day, int year) { return true; } public boolean equals( Object other ) { if ((other instanceof Date) &amp;&amp; ((((Date)other).year==year) &amp;&amp; (((Date)other).month==month) &amp;&amp; (((Date)other).day==day))) return true; else return false; } public int hashCode() { return (year + month + day) % 101; } public int compareTo( Date other ) { if (equals(other)) return 0; else if (year &lt; other.year) return -1; else if (year &gt; other.year) return 1; else if (month &lt; other.month) return -1; else if (month &gt; other.month) return 1; else if (day &lt; other.day) return -1; else if (day &gt; other.day) return 1; else return 0; } </code></pre>
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    1. PO
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    1. PTQuestion
    1. USAndreas_D
    1. USDustin E.
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
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      1. PTAnswer
    2. PO
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      1. POJava: Cannot Cast Object to Date in Comparator
      1. This table or related slice is empty.
      1. VTUpMod
    1. CO`java.sql.Date != java.util.Date` (check if you are importing the same type on model class and comparator class)
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      1. POJava: Cannot Cast Object to Date in Comparator
      1. USFrancisco Spaeth
    2. COIs it possible you used different `Date`s (`java.util` vs `java.sql`) or that the Date objects are loaded by different classloaders?
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      1. POJava: Cannot Cast Object to Date in Comparator
      1. USrsp
    3. COI dont think so, I am only importing: import java.util.*; import java.util.Date; import javax.swing.*;
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      1. POJava: Cannot Cast Object to Date in Comparator
      1. USDustin E.
 

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