Classes

As a first step in converting the example Java program to COBOL, gather the classes used.

Java source usually begins with a list of "import" statements that specify the classes used by the program.

The syntax in Java is:

import [packagename.]classname;

When writing COBOL, necessary classes must be listed in the REPOSITORY paragraph, in the CONFIGURATION SECTION.

The syntax for COBOL is:

class logical-class-name as "[packagename.]classname"

Where:

•	logical-class-name is any valid COBOL name of your choice. It is used to reference the class in the COBOL code.

•	[packagename.]classname is the full name of the class, the same name used in the "import" statement in the Java code.

For example, to convert the following Java statement to COBOL:

import java.io.BufferedReader;

Specify the class in the REPOSITORY paragraph as follows:

CONFIGURATION SECTION. REPOSITORY.   class jBufferedReader  as "java.io.BufferedReader"   .

In Java programs, classes of the package “java.lang” are always available, and therefore do not need to be imported; but COBOL programs MUST explicitly import these packages . For example,

class jSystem            as "java.lang.System"

Java offers a shortcut to import all the classes of a package with a single import statement.

The Java syntax is:

import packagename.*

COBOL does not have an equivalent syntax, requiring instead that each class be declared in the REPOSITORY paragraph.

The Java program “import” statements below:

import java.io.BufferedReader; import java.io.InputStreamReader; import java.net.URL; import java.net.URLConnection;

Are translated to the following COBOL declarations:

CONFIGURATION SECTION. REPOSITORY.    class jBufferedReader  as "java.io.BufferedReader"    class jInputStreamReader as "java.io.InputStreamReader"    class jURL     as "java.net.URL"    class jURLConnection   as "java.net.URLConnection"    class jString    as "java.lang.String"    class jSystem    as "java.lang.System"    .

NOTE: Multiple class declarations in the REPOSITORY paragraph are separated by newline characters, not by periods. Ending the paragraph with a period on a line by itself allows additional class declarations to be inserted.

Once the classes are declared, the COBOL procedure division code must be written following the Java source example.