Question: what is the use of + in java
[{'answer': 'Unary plus'}, {'answer': 'Addition', 'provenance': [{'wikipedia_id': '1079500', 'title': 'Java syntax', 'start_paragraph_id': 210, 'start_character': 84, 'end_paragraph_id': 210, 'end_character': 92, 'bleu_score': 1.0, 'section': 'Section::::Reference types.:Interfaces.:Annotations.:Annotation types.\n'}]}, {'answer': 'String concatenation'}]