相关疑难解决方法(0)

我很难过.我这样宣布我的一套:

    private Set<Long> applicationIds;

然后我像这样填充它:

public void setApplicationIds( Set<Long> applicationIds ) {
    this.applicationIds = new TreeSet<Long>( applicationIds );
    this.applications = null;
}

然后我尝试使用它:

public List<Application> getApplications() {
    if ( applications == null ) {
        applications = new ArrayList<Application>();
        if ( applicationIds != null ) {
            for ( Application application : availableApplications ) {
                if ( applicationIds.contains( Long.valueOf( application.getId() ) ) ) {
                    applications.add( application );
                }
            }
        }
    }
    return applications;
}

我最终得到了这个:

java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Long …