code: public static Package getPackage(String packageName) {
          ClassLoader classloader = ClassLoader.getSystemClassLoader();
          return classloader.getPackage(packageName);
      }
docs: Find a package by name in the callers {@code ClassLoader} instance.
  The callers {@code ClassLoader} instance is used to find the package
  instance corresponding to the named class. If the callers
  {@code ClassLoader} instance is null then the set of packages loaded
  by the system {@code ClassLoader} instance is searched to find the
  named package. <p>
  
  Packages have attributes for versions and specifications only if the class
  loader created the package instance with the appropriate attributes. Typically,
  those attributes are defined in the manifests that accompany the classes.
  
  @param name a package name, for example, java.lang.
  @return the package of the requested name. It may be null if no package
  information is available from the archive or codebase.