An intrinsic problem with passing Java strings to COBOL is that Java strings are variable length whereas COBOL strings are fixed length. For COBOL to modify a predefined fixed-length field, you need to wrap the instance in a new instance of the Pointer class. The Pointer class is in the com.microfocus.cobol.lang package.
For example, here is a COBOL program that defines a PIC X(20) data item:
showbytes.cbl: working-storage section. linkage section. 01 lnk-string pic x(20). procedure division using lnk-string. display "lnk-string = " lnk-string. move "Hello from COBOL - 1" to lnk-string. exit program returning 0.
The corresponding Java code would be:
showbytes.java: import com.microfocus.cobol.RuntimeSystem; import com.microfocus.cobol.lang.Pointer; import com.microfocus.cobol.lang.ParameterList; public class showbytes { public static void main(String[] args) throws Exception { String myString = new String("Hello to COBOL"); Pointer ptr2String = new Pointer(myString, 20); RuntimeSystem.cobcall("showbytes", new ParameterList().add(ptr2String)); myString = ptr2String.toString(); System.out.println(myString = ["+myString+"]"); } }