leaf type empty causing build failure & Temp folder created in java path

yang file:

module ospf {
namespace "urn:cisco:params:xml:ns:yang:ospf";
// replace with IANA namespace when assigned
prefix ospf;
revision 2020-10-20

{ description "Initial revision."; }

leaf enabled

{ type boolean; }

leaf abc

{ type empty; }

}

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building onlab-rest 1.6.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] — maven-clean-plugin:2.5:clean (default-clean) @ onlab-rest —
[INFO]
[INFO] — jacoco-maven-plugin:0.7.5.201505241946:prepare-agent (default-prepare-agent) @ onlab-rest —
[INFO] argLine set to -javaagent:/root/.m2/repository/org/jacoco/org.jacoco.agent/0.7.5.201505241946/org.jacoco.agent-0.7.5.201505241946-runtime.jar=destfile=/home/root1/onos/utils/test/target/jacoco.exec -Duser.language=en -Duser.region=US
[INFO]
[INFO] — yangutils-maven-plugin:1.0.0-SNAPSHOT:yang2java (default) @ onlab-rest —
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.224 s
[INFO] Finished at: 2016-05-13T14:29:25+05:30
[INFO] Final Memory: 19M/372M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.onosproject:yangutils-maven-plugin:1.0.0-SNAPSHOT:yang2java (default) on project onlab-rest: Execution default of goal org.onosproject:yangutils-maven-plugin:1.0.0-SNAPSHOT:yang2java failed. NullPointerException -> [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/PluginExecutionException