JAVA CONCURRENT PROGRAM LOG NOT INCLUDE FND_FILE.LOG OF CALLED PLSQL Package

I have a java concurrent program which call a PLSQL Package.

The package will use fnd_file.put_line(fnd_file.log,'XXXX'); to generate debug message in the concurrent log.

Yet the message appears in one instance but not another.

Any clue?

RDBMS : 11.2.0.3.0

Oracle Applications : 12.1.3

XDO Data Engine Version No: 5.6.3

Resp: 51165

Org ID : 564

Request ID: 602885

All Parameters: P_REP_DEF_ID=111:P_REVIEW_PERIOD_ID=119:P_SHOW_EMPNO_FLAG=Y

Data Template Code: HWLE0076

Data Template Application Short Name: HHR

Debug Flag: N

{P_REP_DEF_ID=111, P_SHOW_EMPNO_FLAG=Y, P_REVIEW_PERIOD_ID=119}

Calling XDO Data Engine...