Fixes https://github.com/spring-projects/spring-integration/issues/8643 * First pass - trivial synchronized blocks - Convert the "trivial" `synchronized` block into `ReentrantLock`. * fix checkstyle * use blocking lock * Secon pass - handle multi-lock cases * javadoc + year * addres first batch of review suggestions * fix checkstyle issues * fix the mqtt parent/child lock monitor sharing * fix the mqtt parent/child lock monitor sharing, v2 * patch the stomp test