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    <p>Your Comperator approach would work, but is has a few bugs. First of all I would replace the <code>Double</code>s in <code>MyEntry</code> by <code>double</code>.</p> <p>Comparing <code>Double</code> is not the same as comparing <code>double</code> For example:</p> <pre><code>Double a = 1.0; Double b = 1.0; System.out.println(a == b); System.out.println(a.equals(b)); System.out.println(a.doubleValue()== b.doubleValue()); </code></pre> <p>Will return </p> <pre><code>false true true </code></pre> <p>Then in the comparison you cast to <code>int</code>, but this implies flooring that data. <code>(int) (2 - 1.9)</code> will give <code>0</code> Better is to compare using <code>&lt;</code> and return -1 or 1. </p> <pre><code> public static Comparator&lt;MyEntry&gt; ValueComparator = new Comparator&lt;MyEntry&gt;() { public int compare(MyEntry value1, MyEntry value2) { double rfirst = value1.rank; double rsecond = value2.rank; double dfirst = value1.dist; double dsecond = value2.dist; if (rsecond != rfirst) { return rsecond &lt; rfirst?-1:1; } else if(dsecond!=dfirst){ return dsecond &lt; dfirst ?-1:1; } return 0; } } </code></pre> <p>For your second question you require an index. This could be done in two ways. First option is to include the index in <code>MyEntry</code> like this:</p> <pre><code> public class MyEntry implements Comparable&lt;MyEntry&gt; { private double rank; private double dist; private int index; private static int nextIndex = 0; public MyEntry(double rank, double dist) { this.rank = rank; this.dist = dist; this.index = nextIndex++; } </code></pre> <p>This way you will be able to retain the index but it is not so flexible. </p> <p>A more flexible approach could be to have the index in a separate array, and sort that. </p> <pre><code> class IndexedArrayComparator implements Comparator&lt;Integer&gt;{ MyEntry[] array; public IndexedArrayComparator(MyEntry[] entries){ this.array=entries; } public Integer[] createIndexes(){ Integer[] index = new Integer[array.length]; for(int i =0;i&lt;index.length;i++){ index[i]=i; } return index; } public int compare(Integer i0, Integer i1) { double rfirst = array[i0].rank; double rsecond = array[i1].rank; double dfirst = array[i0].dist; double dsecond = array[i1].dist; if (rsecond != rfirst) { return rsecond &gt; rfirst?-1:1; } else if(dsecond!=dfirst){ return dsecond &gt; dfirst ?-1:1; } return 0; } } </code></pre> <p>You can then use it like this:</p> <pre><code> MyEntry[] entries = new MyEntry[5]; entries[0]= new MyEntry(1.1,5); entries[1]= new MyEntry(1.1,4); entries[2]= new MyEntry(2.1,5); entries[3]= new MyEntry(0.1,3); entries[4]= new MyEntry(3.1,1); IndexedArrayComparator comp = new IndexedArrayComparator(entries); Integer[] index = comp.createIndexes(); Arrays.sort(index,comp); for(int i =0;i&lt;index.length;i++){ MyEntry e = entries[index[i]]; System.out.println(String.format("%2d:r= %3.1f, d= %3.1f" ,index[i],e.rank,e.dist)); } </code></pre> <p>Which will give: </p> <pre><code> 3:r= 0.1, d= 3.0 1:r= 1.1, d= 4.0 0:r= 1.1, d= 5.0 2:r= 2.1, d= 5.0 4:r= 3.1, d= 1.0 </code></pre> <p>The second way of sorting while maintaining the index is also described <a href="https://stackoverflow.com/questions/4859261/get-the-indices-of-an-array-after-sorting">here</a>. Credits to Jon Skeet</p>
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