Reduce Redundancy: Java language fixes

[saurabh-rahate]

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized it.
• All filenames are in PascalCase.
• All functions and variable names follow Java naming conventions.
• All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.

This PR contains

1. Switch case instead of if-else-if for better readability
2. Usage of enhanced for loop instead of iterator while loop
3. Usage of collection bulk operation instead of manual loop add
4. Removal of redundant Collection.addAll
5. Simplification of switch case
6. Replacement of C style array declaration with Java style array declaration

[siriak]

Well done, thanks!