Here is an example of using the ProxyCollectionWriter class from the Apache Commons IO library in Java to write a collection of items to a Writer:

import java.io.IOException;
import java.io.StringWriter;
import java.util.Arrays;
import java.util.List;
import org.apache.commons.io.output.ProxyWriter;

public class ProxyCollectionWriterExample {
    public static void main(String[] args) {
        // create a new StringWriter
        StringWriter writer = new StringWriter();
        
        // create a list of items
        List<String> items = Arrays.asList("item1", "item2", "item3");
        
        try (ProxyWriter proxyWriter = new ProxyWriter(writer)) {
            // write the collection of items to the Writer
            proxyWriter.write(items);
        } catch (IOException e) {
            e.printStackTrace();
        }
        
        System.out.println(writer.toString());
    }
}

In this example, a ProxyWriter object is created by passing a StringWriter object as an argument. The ProxyWriter class is a decorator for Writer, it provides the ability to write a collection of items to the Writer.

The write(Collection< ? > data) method is used to write the collection of items to the Writer, in this case, a list of strings.

The ProxyWriter class provides a convenient way to write a collection of items to a Writer, it can be useful when you need to write a large amount of data to a Writer and you want to write it in small chunks. The write(Collection< ? > data) method writes all elements of the collection to the Writer using