Illegal character for a namespace of Hbase table using Spark

I am writing data into HBase table using Spark based on this example: https://github.com/apache/hbase/blob/master/hbase-spark/src/main/java/org/apache/hadoop/hbase/spark/example/hbasecontext/JavaHBaseBulkPutExample.java

This line of code at the position of TableName.valueOf("bulkPutTest")

hbaseContext.bulkPut(rdd, TableName.valueOf("bulkPutTest"), new PutFunction());

throws an error

ERROR ApplicationMaster - User class threw exception: 
java.lang.IllegalArgumentException: Illegal character <61> at 5. Namespaces can only contain 'alphanumeric characters': i.e. [a-zA-Z_0-9]: 
    at org.apache.hadoop.hbase.TableName.isLegalNamespaceName(TableName.java:221)

The HBase table was created in hbase-shell using create 'bulkPutTest', {NAME => 'cf'}