Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java (default-cli) on project fyp-storm-try: The parameters 'mainClass' for goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java are missing or invalid -> [Help 1]

ubuntu@ip-10-0-0-101:~/storm/examples/fyp-storm-try$ sudo mvn compile exec:java
-D storm.topology=fyp.storm.try.Topology
[INFO] Scanning for projects...
[WARNING]
[WARNING] Some problems were encountered while building the effective model for org.apache.storm:fyp-storm-try:jar:0.9.4
[WARNING] 'reporting.plugins.plugin.version' for org.apache.maven.plugins:maven-javadoc-plugin is missing. @ org.apache.storm:storm:0.9.4, /root/.m2/repository/org/apache/storm/storm/0.9.4/storm-0.9.4.pom, line 694, column 21
[WARNING] 'reporting.plugins.plugin.version' for org.apache.maven.plugins:maven-surefire-report-plugin is missing. @ org.apache.storm:storm:0.9.4, /root/.m2/repository/org/apache/storm/storm/0.9.4/storm-0.9.4.pom, line 660, column 21
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING]
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING]
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building fyp-storm-try 0.9.4
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] — maven-remote-resources-plugin:1.2.1:process (default) @ fyp-storm-try —
[INFO]
[INFO] — maven-resources-plugin:2.5:resources (default-resources) @ fyp-storm-try —
[debug] execute contextualize
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /home/ubuntu/storm/examples/fyp-storm-try/multilang
[INFO] Copying 3 resources
[INFO]
[INFO] — maven-compiler-plugin:3.1:compile (default-compile) @ fyp-storm-try —
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 5 source files to /home/ubuntu/storm/examples/fyp-storm-try/target/classes
[INFO]
[INFO] — clojure-maven-plugin:1.3.18:compile (compile) @ fyp-storm-try —
[INFO]
[INFO] >>> exec-maven-plugin:1.2.1:java (default-cli) @ fyp-storm-try >>>
[INFO]
[INFO] <<< exec-maven-plugin:1.2.1:java (default-cli) @ fyp-storm-try <<<
[INFO]
[INFO] — exec-maven-plugin:1.2.1:java (default-cli) @ fyp-storm-try —
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 10.364s
[INFO] Finished at: Wed Apr 01 12:43:59 UTC 2015
[INFO] Final Memory: 19M/51M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java (default-cli) on project fyp-storm-try: The parameters 'mainClass' for goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java are missing or invalid -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginParameterException