OmPatel

Results 4 issues of OmPatel

- [x] I have read [CONTRIBUTING.md](https://github.com/TheAlgorithms/Java/blob/master/CONTRIBUTING.md). - [x] This pull request is all my own work -- I have not plagiarized it. - [x] All filenames are in PascalCase. -...

Added null cases to string package. StringFunctions.java file needed the null cases in two methods.

I implemented handling the null and empty string fix on the two functions in the string package in this repository. #### By submitting this pull request I confirm I've read...

#### By submitting this pull request I confirm I've read and complied with the below requirements. - [ ] I have read the [Contribution guidelines](CONTRIBUTING.md) and I am confident that...