Prototyping a constructor of java String class

Hello community,
I want to have a prototype for the constructor method of String class that 
allows passing any literal or character varying variable. I think it might look 
like this:
D String...                                                      
d                 PR              O   extproc( *JAVA             
d                                            : 'java.lang.String'
d                                            : *CONSTRUCTOR)     
d  chars                     65535A   varying                    
d                                     options(*VARSIZE)          
d                                     const

I am not sure whether the ultimate size 65535 of the character parameter  has 
some side or harmful effect or not. What I am afraid of is this:
Let's have this free-form row of a code:
mystring = String( 'Hello' );
If I understand RPG Reference manual correctly RPG compilator generates a 
temporary for the literal that further passes to the method. What is the format 
of the temporary? Is the format 65535A (and varying ?) which would be rather 
unpleasant of the compiler, or 5A (and varying ?) which would be nice I suppose 
??
I am just deducing using information in RPG manuals; maybe I got lost in my 
deductions. The prototypes I found on the web vary in both the length of char 
parameter and the applied keywords.

We are on V5R2.
Thanks in advance for attention, help will be highly appreciated.

Otto Steffan