This was happening to us, and I finally figured out our problem, maybe this can help you.
First, if you are not seeing the console output, use the rioLog plugin
https://wpilib.screenstepslive.com/s...anual-id=13809
We saw these messages:
ž” Launching «'/usr/local/frc/JRE/bin/java' '-jar' '/home/lvuser/FRCUserProgram.jar'»
Error at edu.wpi.first.wpilibj.RobotBase.main(RobotBase.jav a:206): ERROR Unhandled exception instantiating robot org.usfirst.frc.team192.robot.Robot java.lang.ClassNotFoundException: org.usfirst.frc.team192.robot.Robot at [java.net.URLClassLoader$1.run(URLClassLoader.java: 372), java.net.URLClassLoader$1.run(URLClassLoader.java: 361), java.security.AccessController.doPrivileged(Native Method), java.net.URLClassLoader.findClass(URLClassLoader.j ava:360), java.lang.ClassLoader.loadClass(ClassLoader.java:4 24), sun.misc.Launcher$AppClassLoader.loadClass(Launche r.java:308), java.lang.ClassLoader.loadClass(ClassLoader.java:3 57)
This was a clue for us, because 192 was our prototype robot. Even though the package for our final robot was 191, I forgot to change it in the build.properties file, which looks like this:
# Project specific information
package=org.usfirst.frc.team192.robot
robot.class=${package}.Robot
simulation.world.file=/usr/share/frcsim/worlds/GearsBotDemo.world
#Uncomment and point at user libraries to include them in the build. Do not put libraries in the \wpilib\java folder, this folder is completely overwritten on plugin update.
#userLibs=${user.home}/wpilib/user/lib
I changed the 192 to 191 and voila, robot code.