code: @Test public void getNestedJarFile() throws Exception {
    JarFile nestedJarFile=this.jarFile.getNestedJarFile(this.jarFile.getEntry("nested.jar"));
    Enumeration<java.util.jar.JarEntry> entries=nestedJarFile.entries();
    assertThat(entries.nextElement().getName(),equalTo("META-INF/"));
    assertThat(entries.nextElement().getName(),equalTo("META-INF/MANIFEST.MF"));
    assertThat(entries.nextElement().getName(),equalTo("3.dat"));
    assertThat(entries.nextElement().getName(),equalTo("4.dat"));
    assertThat(entries.nextElement().getName(),equalTo("\u00E4.dat"));
    assertThat(entries.hasMoreElements(),equalTo(false));
    InputStream inputStream=nestedJarFile.getInputStream(nestedJarFile.getEntry("3.dat"));
    assertThat(inputStream.read(),equalTo(3));
    assertThat(inputStream.read(),equalTo(-1));
    URL url=nestedJarFile.getUrl();
    assertThat(url.toString(),equalTo("jar:" + this.rootJarFile.toURI() + "!/nested.jar!/"));
    JarURLConnection conn=(JarURLConnection)url.openConnection();
    assertThat(conn.getJarFile(),sameInstance(nestedJarFile));
    assertThat(conn.getJarFileURL().toString(),equalTo("jar:" + this.rootJarFile.toURI() + "!/nested.jar"));
  }
  