CREATE OR REPLACE FUNCTION simpletest()
  RETURNS bigint AS
$BODY$
BEGIN
   
   return 10;
END;
$BODY$
  LANGUAGE plpgsql

ERROR: syntax error at or near ")"
  Position: 20
Error Code: 0
Call: EXECUTE simpletest()
Query: DataReadQuery(name="simpletest" )

@NamedStoredProcedureQuery(name="simpletest", procedureName="simpletest")
public class Student

public void exec()
    {
        Query createNamedQuery = entityManager.createNamedQuery("simpletest");
        System.out.println(createNamedQuery.getResultList());
        
    }

public String getProcedureCallHeader() {
        return "EXECUTE ";
    }

org.eclipse.persistence.platform.database.PostgreSQLPlatform

@NamedStoredProcedureQuery(name = DocumentAccess.CONTAINS_DOC_BY_ANOTHER_OWNER, procedureName = "contains_doc_by_another_owner", parameters = {
                @StoredProcedureParameter(queryParameter = "commaSeparatedIds", type = String.class, direction=Direction.IN),
                @StoredProcedureParameter(queryParameter = "uid", type = Long.class, direction=Direction.IN), 
                @StoredProcedureParameter(queryParameter = "has_another_owner", type = Boolean.class, direction= Direction.OUT),
                @StoredProcedureParameter(queryParameter = "doc_id", type = Long.class, direction= Direction.OUT)}, resultSetMappings = { DocumentAccess.CONTAINS_DOC_BY_ANOTHER_OWNER }),

select has_another_owner, doc_id from contains_doc_by_another_owner(?,?)

public class PostgresqlPlatform extends PostgreSQLPlatform
{

    @Override
    public String getProcedureCallHeader()
    {
        return "SELECT * FROM ";
    }

    @Override
    public boolean shouldPrintStoredProcedureArgumentNameInCall()
    {
        return false;
    }

}