{"action":"created","issue":{"url":"https://api.github.com/repos/MOEAFramework/MOEAFramework/issues/2","labels_url":"https://api.github.com/repos/MOEAFramework/MOEAFramework/issues/2/labels{/name}","comments_url":"https://api.github.com/repos/MOEAFramework/MOEAFramework/issues/2/comments","events_url":"https://api.github.com/repos/MOEAFramework/MOEAFramework/issues/2/events","html_url":"https://github.com/MOEAFramework/MOEAFramework/issues/2","id":106991291,"number":2,"title":"Island-Model Parallelization Example IllegalArgumentException","user":{"login":"Nozo","id":5185195,"avatar_url":"https://avatars.githubusercontent.com/u/5185195?v=3","gravatar_id":"","url":"https://api.github.com/users/Nozo","html_url":"https://github.com/Nozo","followers_url":"https://api.github.com/users/Nozo/followers","following_url":"https://api.github.com/users/Nozo/following{/other_user}","gists_url":"https://api.github.com/users/Nozo/gists{/gist_id}","starred_url":"https://api.github.com/users/Nozo/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/Nozo/subscriptions","organizations_url":"https://api.github.com/users/Nozo/orgs","repos_url":"https://api.github.com/users/Nozo/repos","events_url":"https://api.github.com/users/Nozo/events{/privacy}","received_events_url":"https://api.github.com/users/Nozo/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2015-09-17T13:59:04Z","updated_at":"2015-09-18T08:00:17Z","closed_at":null,"body":"I try to use the island model parallelization code example of the MOEA Framework documentation v2.5 chapter 10.2. With the orignal code form the document sometimes a IllegalArgumentException is thrown from one of the created threads. \r\nDo you have any idear whats the problem in this example?\r\n\r\nException in thread \"Thread-3\" java.lang.IllegalArgumentException: Comparison method violates its general contract!\r\n\tat java.util.TimSort.mergeHi(Unknown Source)\r\n\tat java.util.TimSort.mergeAt(Unknown Source)\r\n\tat java.util.TimSort.mergeCollapse(Unknown Source)\r\n\tat java.util.TimSort.sort(Unknown Source)\r\n\tat java.util.TimSort.sort(Unknown Source)\r\n\tat java.util.Arrays.sort(Unknown Source)\r\n\tat java.util.Collections.sort(Unknown Source)\r\n\tat org.moeaframework.core.Population.sort(Population.java:273)\r\n\tat org.moeaframework.core.NondominatedSortingPopulation.sort(NondominatedSortingPopulation.java:151)\r\n\tat org.moeaframework.core.Population.truncate(Population.java:285)\r\n\tat org.moeaframework.core.NondominatedSortingPopulation.truncate(NondominatedSortingPopulation.java:160)\r\n\tat org.moeaframework.core.NondominatedSortingPopulation.truncate(NondominatedSortingPopulation.java:170)\r\n\tat org.moeaframework.algorithm.NSGAII.iterate(NSGAII.java:97)\r\n\tat org.moeaframework.algorithm.AbstractAlgorithm.step(AbstractAlgorithm.java:161)\r\n\tat org.moeaframework.algorithm.PeriodicAction.step(PeriodicAction.java:108)\r\n\tat AlgThread.run(AlgThread.java:15)\r\n\r\n\r\n"},"comment":{"url":"https://api.github.com/repos/MOEAFramework/MOEAFramework/issues/comments/141374711","html_url":"https://github.com/MOEAFramework/MOEAFramework/issues/2#issuecomment-141374711","issue_url":"https://api.github.com/repos/MOEAFramework/MOEAFramework/issues/2","id":141374711,"user":{"login":"Nozo","id":5185195,"avatar_url":"https://avatars.githubusercontent.com/u/5185195?v=3","gravatar_id":"","url":"https://api.github.com/users/Nozo","html_url":"https://github.com/Nozo","followers_url":"https://api.github.com/users/Nozo/followers","following_url":"https://api.github.com/users/Nozo/following{/other_user}","gists_url":"https://api.github.com/users/Nozo/gists{/gist_id}","starred_url":"https://api.github.com/users/Nozo/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/Nozo/subscriptions","organizations_url":"https://api.github.com/users/Nozo/orgs","repos_url":"https://api.github.com/users/Nozo/repos","events_url":"https://api.github.com/users/Nozo/events{/privacy}","received_events_url":"https://api.github.com/users/Nozo/received_events","type":"User","site_admin":false},"created_at":"2015-09-18T08:00:17Z","updated_at":"2015-09-18T08:00:17Z","body":"Hi dhadka, \r\n\r\nI use Windows 7  and the Java version 7 with update 79. \r\nthe exception is only  thrown from time to time and the code finishes his job but for later development based on your example it is important for me to fix this issue. \r\n\r\nTanks for your time! "}}