As part of the major changes in 3.0, the way to log to the user log, now neo4j.log (in server mode), has changed. To log within a Server Plugin follow these steps:

  1. Include these packages: 
    import org.neo4j.logging.Log;
import org.neo4j.logging.LogService;
import org.neo4j.kernel.internal.GraphDatabaseAPI;
  2. In the method for the Server Plugin, you need the following code to use the logger: 
    @PluginTarget(GraphDatabaseService.class)
    public Iterable<String> getAllLabels(@Source GraphDatabaseService graphDb) {
        LogService logService = ((GraphDatabaseAPI)graphDb).getDependencyResolver().resolveDependency( LogService.class );
        Log log = logService.getUserLog( getClass() );
  3. Now log using the appropriate method for the log object: 
    log.info( "Hello world!" );
log.debug( "Hello debuggers!" );

We get a log that contains lines like this:

2016-12-05 17:33:21.223+0000 INFO  Hello world!
2016-12-05 17:33:21.345+0000 DEBUG  Hello debuggers!

Details

Author:
Dave Gordon
Applicable versions:
3.0, 3.1
Keywords:
Java API • logging • neo4j-3.0 • neo4j-3.1 • plugin