DATA DIVISION for defining a class instance method

The DATA DIVISION of an instance method consists of any of the following four sections: FILE SECTION, LOCAL-STORAGE SECTION, WORKING-STORAGE SECTION, and LINKAGE SECTION.

FILE SECTION
The same as a program FILE SECTION, except that a method FILE SECTION can define EXTERNAL files only.
LOCAL-STORAGE SECTION
A separate copy of the LOCAL-STORAGE data is allocated for each invocation of the method, and is freed on return from the method. The method LOCAL-STORAGE SECTION is similar to a program LOCAL-STORAGE SECTION.

If you specify the VALUE clause on a data item, the item is initialized to that value on each invocation of the method.

WORKING-STORAGE SECTION
A single copy of the WORKING-STORAGE data is allocated. The data persists in its last-used state until the run unit ends. The same copy of the data is used whenever the method is invoked, regardless of the invoking object or thread. The method WORKING-STORAGE SECTION is similar to a program WORKING-STORAGE SECTION.

If you specify the VALUE clause on a data item, the item is initialized to that value on the first invocation of the method. You can specify the EXTERNAL clause for the data items.

LINKAGE SECTION
The same as a program LINKAGE SECTION.

If you define a data item with the same name in both the DATA DIVISION of an instance method and the DATA DIVISION of the OBJECT paragraph, a reference in the method to that data-name refers only to the method data item. The method DATA DIVISION takes precedence.

Related references  
DATA DIVISION overview (Enterprise COBOL for z/OS® Language Reference)