Why SQLJ cannot find error?

I have tested the sample program, TestInstallSQLJChecker.sql

My connect.prpoerties is

sqlj.url=jdbc:oracle:oci8:@
sqlj.driver=oracle.jdbc.driver.OracleDriver
sqlj.user=scott
sqlj.password=tiger      

If I run
sqlj TestInstallSQLJChecker.sql
There is no error!

However, if I run
sqlj -user=scott TestInstallSQLJChecker.sql The SQLJ checker can find the syntax error in my SQL statement.

Oarcle hoempage says that
"Online semantics-checking is enabled as soon as you specify a username for the translation-time database connection. You can specify the username either by uncommenting the sqlj.user line in the sqlj.properties file or by using the -user command-line option"

Why I still need to specify username in command even I have specified it in connect.properties ?

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