OK, let's go step by step:
1) UnusedImportsCheck - you know what to do
2) MultipleStringLiteralsCheck - use ```// @checkstyle MultipleStringLiterals (1 line)```. Specify number of lines to skip MultipleStringLiteralsCheck to
3) LineLengthCheck - try to split the line or add suppression as in case 2
4) RequireThisCheck - add ```this``` to access instance variable