utils/src/main/java/org/robolectric/util/inject/ServiceFinder.java
public static <S> S loadFromSystemProperty(final Class<S> service) {
    try {
      final String className = System.getProperty(service.getName());
      if (className != null) {
        Class<?> c = ClassLoader.getSystemClassLoader().loadClass(className);
        return (S) c.newInstance();
      }
      return null;
    } catch (Exception e) {
      throw new Error(e);
    }
  }
public static <S> S loadFromSystemProperty(final Class<S> service) {
    try {
      final String className = System.getProperty(service.getName());
      if (className != null) {
        Class<?> c = ClassLoader.getSystemClassLoader().loadClass(className);
        return (S) c.newInstance();
      }
      return null;
    } catch (Exception e) {
      throw new Error(e);
    }
  }
Internal API to support built-in SPIs that check a system property first.
Returns an instance specified by a property with the class' binary name, or null if
no such property is set.
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