public static String getPackageName(Class<?> clazz) {
        Preconditions.checkNotNull(clazz, "Class must not be null");
        return getPackageName(clazz.getName());
    }
public static String getPackageName(Class<?> clazz) {
        Preconditions.checkNotNull(clazz, "Class must not be null");
        return getPackageName(clazz.getName());
    }
public static String getPackageName ( Class < ? > clazz ) { Preconditions . checkNotNull ( clazz , "Class must not be null" ) ; return getPackageName ( clazz . getName ( ) ) ; }
Determine the name of the package of the given class,
e.g. "java.lang" for the {@code java.lang.String} class.

@param clazz the class
@return the package name, or the empty String if the class
is defined in the default package
Determine the name of the package of the given class e . g . java . lang for the { @code java . lang . String } class .