IntervalScheduling

[iamkaniska]

• 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.
• All new code is formatted with clang-format -i --style=file path/to/your/file.java

[siriak]

The code looks good, could you please replace main with a function with parameters and add some JUnit tests? (see https://github.com/TheAlgorithms/Java/tree/master/src/test/java/com/thealgorithms)