There are more than one leg level to set.
- org.netbeans.level
- snap.log.level
- snap.worldwind.logLevel
As value the following settings are allowed: OFF | SEVERE | WARNING | INFO | CONFIG | FINE | ALL
e.g.:
snap.log.level=SEVERE
You can put those either in the snap.properties of the etc directory in the SNAP installation folder or add them on the command line. Prepending -D