ghillert/spring-integration — comment on commit 9761c030fa12e756c1a9510525362ef2c069b0dc
File: spring-integration-jdbc/src/main/java/org/springframework/integration/jdbc/StoredProcExecutor.java line 158
By ghillert:

Because in the default mode (when no *Stored Procedure Parameters* are provided using the ** sub-element) then a *BeanPropertySqlParameterSourceFactory* is used that will try to match the bean properties of the payload with the Stored Procedure parameters that were either detected from the JDBC Meta data or that were provided 'by-hand' using **. However, if ** are provided an instance of *ExpressionEvaluatingSqlParameterSourceFactory* is expected.