Question

My attempt to customize the method contains of ArrayList, I used Eclipse to generate these methods inside a class TaskCandidateListItemDo

@Override
public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result;

    if (keyValue == null) {
        result += 0;
    } else {
        result += keyValue.hashCode();
    }

    return result;
}

@Override
public boolean equals(Object obj) {
    if (this == obj) {
        return true;
    }
    if (obj == null) {
        return false;
    }
    if (getClass() != obj.getClass()) {
        return false;
    }

    TaskOverrideItemDo other = (TaskOverrideItemDo) obj;

    if (keyValue == null) {
        if (other.keyValue != null) {
            return false;
        }
    } else if (!keyValue.equals(other.keyValue)) {
        return false;
    }
    return true;
}

And here’s is how I use it

taskCandidateList = (List<TaskCandidateListItemDo>) namedQuery.list();

for (TaskOverrideItemDo taskOverrideItemDo : validateOverrideListSearchCriteriaDo
        .getTaskOverrideItemDoList()) {

    if (taskCandidateList.contains(taskOverrideItemDo.getKeyValue())) {
       // do some code
    }
}

My list declared as followed

private List<TaskCandidateListItemDo> taskCandidateList;

The // do some code inside the if statement is never executed even if keyValue exist. Also, the break point wouldnt stop at the equals method..

Answer 1

Try with:

if (taskCandidateList.contains(taskOverrideItemDo)) {

Without getKeyValue(), I suppose it returns the value of the field keyValue (and your equals method compares only TaskCandidateListItemDo because of:

if (getClass() != obj.getClass()) {
    return false;
}

As alternative you may support comparison with the type of keyValue inside the equals method.