Logging fixed

Using string concatenation "foo=" + bar + " x=" + x" in logging is horribly bad. The SLF4J avoids that by creating the log message string on demand (if current log level must be logged).

Replace ALL loggers with org.slf4j.Logger and make sure they are called LOG:

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

...

Logger LOG = LoggerFactory.getLogger(...

Replace all string concatenation in calls to LOG.info, LOG.debug, etc. with message format logging:

LOG.info("Test value=" + value + " other=" + other);
// must be
LOG.info("Test value={} other={}", value, other);