@Contended on class may break the field alignment

if specified ContendedPaddingWidth isn't quite correct, in the annotated by @Contended class fields will be not aligned.

excerpts from output 'runtime/8003985/Test8003985' with -XX:+PrintFieldLayout and XX:ContendedPaddingWidth=257:

Test8003985$Test7: field layout
  @269 --- instance fields start ---
  @269 "int1" I
  @273 "int2" I
  @269 --- instance fields end ---
  @536 --- instance ends ---
  @ 88 --- static fields start ---
  @608 --- static fields end ---

Test7.int2 isn't aligned.

suggested fix:
'ContendedPaddingWidth' value must be corrected during starting