Refactoring: misc part 3

For easier code reading the following refactoring can be done:
- 'equals()' expression replaceable by 'Objects.equals()' expression
- Explicit type can be replaced with <>
- Identical 'catch' branches in 'try' statement
- Simplify catch blocks
- 'try finally' replaceable with 'try' with resources,
- Add t-w-r where applicable
- update BaseWriter, Reader, Classpath, MultipleFileReader to be autocloseable
- replace some simple while loops with foreach
- 'if' replaceable with 'switch'
- String concatenation as argument to 'StringBuilder.append()' call