S6857 checks for the valid syntax of Spring property placeholders and Spring Expression Language (SpEL) expressions. Property placeholders can have a more complex default value than what is currently covered by the rule implementation. E.g.:

The current implementation allows for default values of the following form:

• #{...} - an SpEL expression that is checked for valid syntax

• any valid property name or number, including member select and index expressions

The following can also occur and are currently not covered:

• ${...} - a nested property placeholder that needs to be checked for valid syntax, as in ${foo.bar:${baz}}

• any contents that does not start with #{ or ${, as in ${foo.bar:0 0 * 8 b c

• empty contents, as in ${foo.bar:}