&& (summary.hasTeacher() || (summary.getTeacherName() != null || !summary .getTeacher().equals("")))) {
&& (summary.hasTeacher() || (summary.getTeacherName() != null && !summary .getTeacherName().equals("")))) {
    public List<Summary> readSummariesOfTeachersWithoutProfessorship() {        List<Summary> summaries = new ArrayList<Summary>();        for (Summary summary : this.getAssociatedSummaries()) {            if (!summary.hasProfessorship()                    && (summary.hasTeacher() || (summary.getTeacherName() != null || !summary                            .getTeacher().equals("")))) {                summaries.add(summary);            }        }        return summaries;    }