It depends on table definition. If you define your table with a PK that is not auto-increment (default) then you sure can pass your own ID. 

You can assign your own ID: CREATE TABLE mytable (field1 INT PRIMARY KEY, field2 VARCHAR2)

https://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY...

Try looking at this https://github.com/intersystems-community/iris-driver-distribution

Even though the driver is listed in maven repos it doesn't download. You need to [manually] include the library in your project.

Can you show the query plan? Usually this issue "shows" when indices are out of sync. Maybe try rebuilding indices.

The list of steps depend on how is your current application built (e.g. are you using direct global access vs. SQL). Depending on which direction you want to go you could simply wrap your existing objectscript code in either stored procs or services and access them from Java or rewrite all your existing logic in Java.

Again, the steps would depend on what exactly you're trying to accomplish and your current app makings.

The "||" is used to concatenate. So that's why it makes sense those are the ones used in the SQL you pasted instead of "!!".

The error should be in the %objlasterror variable. You would have to check: if %New() returned a new instance, if not then check the value of %objlasterror. Then perform any error handling you'd like to do. 

try/catch doesn't work because %New() doesn't throw any exceptions.

It's hard to tell what's wrong without all (or more) details. Are you getting an error? If you're not getting an error, are you passing the correct values (values that should return records)? Also, have you tried creating a very basic stored proc in Oracle (select current_date from dual or something like that) and try to use that from IRIS? The exercise will help you eliminate variables for possible issues.

You can map an Oracle Stored procedure to IRIS method using the SQL Gateway. Once the mapping is done, you can expose it with a service or any other means IRIS provides.

To add a new header, you need to create a subclass of %SOAP.Header with the property you need. Once you have that then you can add it to the appropriate array e.g.

S myheader = ##class(MyNewHeader).%New()

S myheader.mykeyproperty = <myvalue>

D myservice.HeadersOut.SetAt(myheader,"MyNewHeader")

This is assuming the header is not automatically generated from the XML schema.

Since you're using ObjectScript you should get the value from the list using something like $LISTGET(CList,i). That should return the correct value without control chars. 

If you still want to use $PIECE then SET CListString = $LISTTOSTRING(CList) and then use the $PIECE on the CListString