code: void appendToBootstrapClassLoaderSearch(InputStream jarStream) throws IOException {
          File jarFile = File.createTempFile("mockito-boot", ".jar");
          jarFile.deleteOnExit();
  
          byte[] buffer = new byte[64 * 1024];
          try (OutputStream os = new FileOutputStream(jarFile)) {
              while (true) {
                  int numRead = jarStream.read(buffer);
                  if (numRead == -1) {
                      break;
                  }
  
                  os.write(buffer, 0, numRead);
              }
          }
  
          nativeAppendToBootstrapClassLoaderSearch(jarFile.getAbsolutePath());
      }
docs: Append the jar to be bootstrap class load. This makes the classes in the jar behave as if
  they are loaded from the BCL. E.g. classes from java.lang can now call the classes in the
  jar.
  
  @param jarStream stream of jar to be added