code: public Enumeration<? extends ZipEntry> entries() {
          ensureOpen();
          return new Enumeration<ZipEntry>() {
                  private int i = 0;
                  public boolean hasMoreElements() {
                      synchronized (ZipFile.this) {
                          ensureOpen();
                          return i < total;
                      }
                  }
                  public ZipEntry nextElement() throws NoSuchElementException {
                      synchronized (ZipFile.this) {
                          ensureOpen();
                          if (i >= total) {
                              throw new NoSuchElementException();
                          }
                          long jzentry = getNextEntry(jzfile, i++);
                          if (jzentry == 0) {
                              String message;
                              if (closeRequested) {
                                  message = "ZipFile concurrently closed";
                              } else {
                                  message = getZipMessage(ZipFile.this.jzfile);
                              }
                              throw new ZipError("jzentry == 0" +
                                                 ",\n jzfile = " + ZipFile.this.jzfile +
                                                 ",\n total = " + ZipFile.this.total +
                                                 ",\n name = " + ZipFile.this.name +
                                                 ",\n i = " + i +
                                                 ",\n message = " + message
                                  );
                          }
                          ZipEntry ze = getZipEntry(null, jzentry);
                          freeEntry(jzfile, jzentry);
                          return ze;
                      }
                  }
              };
      }
docs: Returns an enumeration of the ZIP file entries.
  @return an enumeration of the ZIP file entries
  @throws IllegalStateException if the zip file has been closed