JPA enable a tagging of large objects with the annotation @Lob. Java provides in addition two interfaces java.sql.Blob and java.sql.Clob to support the handling of Lobs. The interfaces have to be implemnted individually by each database provider, which makes it difficult to create a generic solution. Nevertheless they are supported in general.
Independent from the used type, if a property is annotated with @Lob maxlength is suppressed.
For Blob:
If JPA entity property is either of type byte[] or java.sql.Blob and annotated with @Lob the corresponding EDM property will get type Edm.Binary.
For Clob:
If JPA entity property is either of type String or java.sql.Clob and annotated with @Lob the corresponding EDM property will get type as Edm.String.
Olingo itself does not support java.sql.Blob or java.sql.Clob. Therefore the Result Converter has to switch the type from Blob to byte[] respectifly Clob to String by calling getBytes(long pos, int length) or getSubString(long pos, int length).
JPA does not have the option to create Blob or Clob instances. Therefore the JPA Processor provides the data as byte[] or String. Within the JPA CUD Handler implementation the data have to be converted into an DB specific implmentation of java.sql.Blob or java.sql.Clob.