Difference in error when no name is mentioned for identifier with and without quotes

Defect : Difference in error when no name is mentioned for identifier with and without quotes

Yang with quotes :
module moduletest {
yang-version 1;
namespace "onos-yang-10:level1:newlevel";
prefix test;

organization "huawei";
contact "adarsh.m@huawei.com";
description "Containers and list scenario";

revision 2015-02-05;
container " " {

}
}

Yang without quotes:
module moduletest {
yang-version 1;
namespace "onos-yang-10:level1:newlevel";
prefix test;

organization "huawei";
contact "adarsh.m@huawei.com";
description "Containers and list scenario";

revision 2015-02-05;
container {

}
}

ERROR WITH QUOTES :

root1@root1-HP-EliteBook-840-G2:/opt/onos-master/onos/utils/test$ mvn clean install
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building onlab-test 1.6.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] — maven-clean-plugin:2.5:clean (default-clean) @ onlab-test —
[INFO] Deleting /opt/onos-master/onos/utils/test/target
[INFO]
[INFO] — jacoco-maven-plugin:0.7.5.201505241946:prepare-agent (default-prepare-agent) @ onlab-test —
[INFO] argLine set to -javaagent:/home/root1/.m2/repository/org/jacoco/org.jacoco.agent/0.7.5.201505241946/org.jacoco.agent-0.7.5.201505241946-runtime.jar=destfile=/opt/onos-master/onos/utils/test/target/jacoco.exec -Duser.language=en -Duser.region=US
[INFO]
[INFO] — yangutils-maven-plugin:1.0.0-SNAPSHOT:yang2java (default) @ onlab-test —
[INFO] Error in file: /opt/onos-master/onos/utils/test/src/main/yang/Onos_Yang_10.yang at line: 11 at position: 4
YANG file error : container name is not valid.
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.794 s
[INFO] Finished at: 2016-05-13T17:54:03+05:30
[INFO] Final Memory: 19M/315M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.onosproject:yangutils-maven-plugin:1.0.0-SNAPSHOT:yang2java (default) on project onlab-test: 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
root1@root1-HP-EliteBook-840-G2:/opt/onos-master/onos/utils/test$

ERROR WITHOUT QUOTES :

root1@root1-HP-EliteBook-840-G2:/opt/onos-master/onos/utils/test$ mvn clean install
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building onlab-test 1.6.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] — maven-clean-plugin:2.5:clean (default-clean) @ onlab-test —
[INFO]
[INFO] — jacoco-maven-plugin:0.7.5.201505241946:prepare-agent (default-prepare-agent) @ onlab-test —
[INFO] argLine set to -javaagent:/home/root1/.m2/repository/org/jacoco/org.jacoco.agent/0.7.5.201505241946/org.jacoco.agent-0.7.5.201505241946-runtime.jar=destfile=/opt/onos-master/onos/utils/test/target/jacoco.exec -Duser.language=en -Duser.region=US
[INFO]
[INFO] — yangutils-maven-plugin:1.0.0-SNAPSHOT:yang2java (default) @ onlab-test —
[INFO] Error in file: /opt/onos-master/onos/utils/test/src/main/yang/Onos_Yang_10.yang at line: 11 at position: 16
no viable alternative at input '{'
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.865 s
[INFO] Finished at: 2016-05-13T18:01:26+05:30
[INFO] Final Memory: 18M/315M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.onosproject:yangutils-maven-plugin:1.0.0-SNAPSHOT:yang2java (default) on project onlab-test: 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
root1@root1-HP-EliteBook-840-G2:/opt/onos-master/onos/utils/test$