with jsr 283 the jcr path is defined to consist of a combination of the following segments
• a name segment, (J, I), where J is a JCR name and I is an integer index (I ≥ 1).
• an identifier segment, U, where U is a JCR identifier.
• the root segment.
• the self segment.
• the parent segment.
-> the name segment can be in extended or qualified form -> see issue
> the identifier segment is new for jsr283 and always identifies a node (> see new method Node.getIdentifier())
Non-standard parts always need to be standardized. Any of the following makes a path non-standard:
- expanded name segments
- trailing /
- index 
- get resolved upon being passed to any API calls that take path to an existing Node
- don't get resolved when being used to create a PATH value object.
Except for PATH values, all jcr paths returned by the API are normalized and standard, thus never identifier-based.
PATH values in contrast:
- must be converted to standard form
- must NOT be normalized. i.e. redundant segments and identifiers must be preserved.