private T getInternal() {
T result = instance;
if (null == result) {
instance = result = creation.call();
}
return result;
}
private T getInternalSync() {
T result = instance;
if (null == result) {
synchronized (this) {
result = instance;
if (null == result) {
instance = result = creation.call();
}
}
}
return result;
}