java null指针异常

if (myObject != null) {
    myObject.someMethod();
} else {
    // Handle the case when myObject is null
}

Optional<MyObject> myObjectOptional = Optional.ofNullable(myObject);
myObjectOptional.ifPresent(obj -> obj.someMethod());

MyObject myObject = Objects.requireNonNull(someMethodThatMayReturnNull(), "myObject cannot be null");

MyObject myObject = someMethodThatMayReturnNull();
if (myObject == null) {
    myObject = new MyObject(); // 使用空对象
}
myObject.someMethod();

Optional<MyObject> myObjectOptional = Optional.of(new MyObject());
MyObject myObject = myObjectOptional.orElseGet(() -> new MyObject());
myObject.someMethod();