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Thread: Exception in thread Main

  1. #1
    Junior Member
    Join Date
    Feb 2018
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    Default Exception in thread Main

    package week4;

    import java.util.HashMap;

    //the class is set as final before release for sharing or use,
    //so that others cannot overwrite
    public final class myClass {

    //set the data to be used by others to be private and final so that it cannot be overwritten.
    private static HashMap<Integer, String> hm;

    //But to allow others to use, need to set as public
    public myClass() {
    myClass.hm = new HashMap <Integer, String>();

    public myClass gethm() {
    return (myClass) hm.clone();


    public static void main(String [] args)
    myClass a = new myClass();


    /*Exception in thread "main" java.lang.ClassCastException: java.util.HashMap cannot be cast to week4.myClass
    at week4.myClass.gethm(myClass.java:18)
    at week4.myClass.main(myClass.java:25)

  2. #2
    Super Moderator Norm's Avatar
    Join Date
    May 2010
    Eastern Florida
    Thanked 2,635 Times in 2,585 Posts

    Default Re: Exception in thread Main

    " java.lang.ClassCastException: java.util.HashMap cannot be cast to week4.myClass
    The error message says what the problem is. A HashMap is not a myClass.

    Please edit your post and wrap your code with code tags:


    to get highlighting and preserve formatting.
    If you don't understand my answer, don't ignore it, ask a question.

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