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Java.lang.classcastexception Java.util.arraylist Cannot Be Cast To Java.lang.comparable

I am looking for a transformer in this case and i tried several options to convert into a FlightArray. Methods which were written to take advantage of polymorphic behavior and coded on interfaces prior to Java 5 and doesn't used parameter to provide type-safety. List fruits = new ArrayList(); fruits.add("Pineapple"); fruits.add("Apple"); fruits.add("Orange"); fruits.add("Banana"); Collections.sort(fruits); int i=0; for(String temp: fruits){ System.out.println("fruits " + ++i + " : " + temp); } Output fruits 1 : Apple SortedSet / SortedMap are interfaces. http://pgexch.com/java-lang-classcastexception-java-util-arraylist/java-lang-classcastexception-java-util-arraylist-cannot-be-cast-to-java-lang-integer.html

Other Java debugging and troubleshooting tutorials How to solve java.util.NoSuchElementException in Java JDBC - java.lang.ClassNotFoundException: com.mysql.jdbc.Driver Solution How to fix java.io.NotSerializableException: org.apache.log4j.Logger Error in Java How to fix java.sql.SQLException: Invalid column How to find middle element of LinkedList in Java i... Comparator vs. HashMap is not Comparable. http://stackoverflow.com/questions/12595097/java-lang-classcastexception-java-util-hashmap-cannot-be-cast-to-java-lang-comp

Refer [this]( http://docs.oracle.com/javase/6/docs/api/java/util/Collections.html#sort%28java.util.List%29): public static

You would have had the same error when using these objects in a TreeMap, or when they were in a List and you sorted it using Collections.sort(List). How to add, modify and drop column with default va... Not the answer you're looking for? Recursion in Java with example - Programming Techn...

Thanks Rob for the above . How to fix java.io.NotSerializableException: org.a... Because your HashMap does not implement Comparable interface.. super T>> void sort(List list) List contain(T) must extends Comparable.

Why is looping over find's output bad practice? Read our privacy policy. How to sort HashMap by key and value in Java - Has... Good programmers write code that humans can understand." --- Martin Fowler Please correct my English.

share|improve this answer answered Sep 26 '12 at 5:42 Michael Chen 953379 add a comment| Your Answer draft saved draft discarded Sign up or log in Sign up using Google http://javarevisited.blogspot.com/2012/12/how-to-solve-javalangclasscastexception-java.html Browse other questions tagged java sorting arraylist hashmap or ask your own question. super T>> void sort(List list) In your case you are trying to sort an ArrayList that contains a HashMap, which does not implements Comparable interface. Wouter Oet Saloon Keeper Posts: 2700 I like...

To do that it either needs a Comparator or if you don't provide one the element-class must implement the Comparable interface. have a peek at these guys So If you have a blog with unique and interesting content then you should check out our JCG partners program. Start a coup online without the government intervening Alternating Fibonacci What crime would be illegal to uncover in medieval Europe? Join them; it only takes a minute: Sign up cannot be cast to java.lang.Comparable up vote 19 down vote favorite 2 import java.util.HashMap; import java.io.*; import java.util.*; public class Fegan implements

XPath Tutorial - How to select elements in XPATH b... Let's begin with a very simple example using arrays of primitive types:ObjectSortingExample.java:package com.javacodegeeks.java.core; import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.List; public class ObjectSortingExample { public static void main(String[] args) { January 2, 2013 at 6:44 PM Anonymous said... check over here The method compareTo you are overidding in it should have a Fegan object as a parameter whereas you are casting it to a FoodItems.

Ravi Kiran Va Ranch Hand Posts: 2234 I like... Arrays.sort(fruits, fruitName, Arrays.ASCENDING); To sort a object array by its "quantity" in ascending order. Message payload is of type: ArrayList Unable to find a transformer to convert the payload using the Return class "com.mulesoft.training.FlightArray" Any suggestions??

posted 6 years ago Till today i was adding Strings so didn't realized that , but when i added Custom Object the concept was clear .

Since due to polymorphism in Java an Object instance can hold any type of Object but you can only cast between same type. If you really need to be able to compare HashMaps, you could create your own HashMap, something like so: public class MyHashMap extends HashMap implements Comparable> { ... JPA Mini Book2. Comparable Check out the comparision and figure out when to use which.

He cant sort, I'm showing him how to do it. –Sergio Oct 16 '13 at 14:25 I edited the question including the calling method of Collections.sort() . –Pathfinder92 Oct What crime would be illegal to uncover in medieval Europe? On 1941 Dec 7, could Japan have destroyed the Panama Canal instead of Pearl Harbor in a surprise attack? http://pgexch.com/java-lang-classcastexception-java-util-arraylist/java-lang-classcastexception-java-util-arraylist-cannot-be-cast-to-java-lang-enum.html How to parse or convert String to long in Java - 4...

Like this question? posted 6 years ago Glad I could help. "Any fool can write code that a computer can understand. Also write your own classes and method to take advantage of Generics to provide type-safety as shown in this example of How to write parameterized class. If you're still confused read this. "Any fool can write code that a computer can understand.

asked 4 years ago viewed 23137 times active 4 years ago Upcoming Events 2016 Community Moderator Election ends Nov 22 Related 3'java.lang.ClassCastException: Resource cannot be cast to java.lang.Comparable'34why HashMap Values are Constantly being on the lookout for partners; we encourage you to join us. We will also see how to minimize or avoid ClassCastException in Java by using Generics, as prevention is always better than cure. public class Counter implements Comparable, java.io.Serializable { private String description; public Counter() { } public Counter(String description) { this.description = description; } public int compareTo(Counter other) { return description.compareTo(other.description); } }