References
1. https://www.javatpoint.com/java-regex
2. http://www.allindiaexams.in/engineering/cse/java-regex-mcq-quiz-java-regex-online-test
3. https://java.meritcampus.com/core-java-questions/Strings1911
4. https://www.sanfoundry.com/java-questions-answers-regular-expression/
5. https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSnVxYO0i6yGk6_yAoRz041lGu_mJQ2NMAyz9FpbzY6Ui4MGogOiQ
6. https://static.javatpoint.com/images/java-regex-api.jpg
7. https://www.javamex.com/tutorials/regular_expressions/StringTokPerf.png
8. https://image.slidesharecdn.com/javaregex-131218113347-phpapp02/95/java-regular-expression-9-638.jpg?cb=1387366523