Error: Could not find or load main class ui.DrawingEditor

I have ubuntu 16.04 installed as my system...

I can't find where the problem is...

The project compiles fine without errors but it won't run

Following is the error message:

/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/bin/java -javaagent:/opt/idea-IC-172.4155.36/lib/idea_rt.jar=37361:/opt/idea-IC-172.4155.36/bin -Dfile.encoding=UTF-8 -classpath /usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/charsets.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/ext/cldrdata.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/ext/dnsns.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/ext/icedtea-sound.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/ext/jaccess.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/ext/localedata.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/ext/nashorn.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/ext/sunec.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/ext/sunjce_provider.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/ext/sunpkcs11.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/ext/zipfs.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/jce.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/jsse.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/management-agent.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/resources.jar:/usr/lib/jvm/java-1.8.0-openjdk-i386/jre/lib/rt.jar:/home/abuakram/Desktop/SoftwareConstruction/DataAbstraction/ConstructionProblems/intro-to-softconst-lecture-starters/SimpleDrawingPlayer/out/production/SimpleDrawingPlayer:/opt/idea-IC-172.4155.36/lib/junit-4.12.jar:/opt/idea-IC-172.4155.36/lib/hamcrest-core-1.3.jar ui.DrawingEditor