How to use Comparator in Java to sort
I learned how to use the comparable but I’m having difficulty with the Comparator. I am having a error in my code: Exception … Read more
comparator
“Comparison method violates its general contract!”
Can someone explain me in simple terms, why does this code throw an exception, “Comparison method violates its general contract!”, and how do … Read more
Sort ArrayList of custom Objects by property
I read about sorting ArrayLists using a Comparator but in all of the examples people used compareTo which according to some research is … Read more
Java : Comparable vs Comparator [duplicate]
When your class implements Comparable, the compareTo method of the class is defining the “natural” ordering of that object. That method is contractually obligated (though not … Read more
Java error: Comparison method violates its general contract
The exception message is actually pretty descriptive. The contract it mentions is transitivity: if A > B and B > C then for … Read more
Java Comparator class to sort arrays
[…] How should Java Comparator class be declared to sort the arrays by their first elements in decreasing order […] Here’s a complete … Read more
Java TreeMap Comparator
You can not sort TreeMap on values. A Red-Black tree based NavigableMap implementation. The map is sorted according to the natural ordering of its keys, … Read more
Sort ArrayList of custom Objects by property
Since Date implements Comparable, it has a compareTo method just like String does. So your custom Comparator could look like this: public class CustomComparator implements Comparator<MyObject> { @Override public int compare(MyObject o1, … Read more
Java get String CompareTo as a comparator object
The Arrays class has versions of sort() and binarySearch() which don’t require a Comparator. For example, you can use the version of Arrays.sort() … Read more