Find all jar files in a directory

All jar files in a directory:

import java.io.File;
import java.io.FilenameFilter;

public class AllFilesInDir {

  public static void main(String[] args) {
      String cp = getClasspath("c:/temp/WEB-INF/lib");
      System.out.println("cp=" + cp);
  }

  private static String getClasspath (String jarlib) {
      String cp = "";
      File dir = new File(jarlib); 
      FilenameFilter filter = new FilenameFilter() {
          public boolean accept(File dir, String name) {
              return name.endsWith(".jar");
          }
      };
      String[] children = dir.list(filter);
      if (children == null) {
          return cp;
      }
       String os = System.getProperty("os.name");
        int pos = os.indexOf("400");
        String deli = pos < 0 ? ";" : ":";
        for (int i=0; i<children.length; i++) {
            String f = children[i];
            cp += f + deli;
            //System.out.println("file=" + f);
        }
  
        return cp;
    }
}