apache-kafka_0_9-lib/src/main/java/org/apache/kafka/common/security/kerberos/LoginManager.java
public static void closeAll() {
        synchronized (LoginManager.class) {
            for (LoginType loginType : new ArrayList<>(CACHED_INSTANCES.keySet())) {
                LoginManager loginManager = CACHED_INSTANCES.remove(loginType);
                loginManager.login.shutdown();
            }
        }
    }
public static void closeAll() {
        synchronized (LoginManager.class) {
            for (LoginType loginType : new ArrayList<>(CACHED_INSTANCES.keySet())) {
                LoginManager loginManager = CACHED_INSTANCES.remove(loginType);
                loginManager.login.shutdown();
            }
        }
    }
/* Should only be used in tests.