Java work for a year, the popular framework will be, the front desk is not proficient also calculate skilled. How to break through the bottleneck? I remember when I graduated from college my resume said I was proficient in Java, after 5 years of work it said I was familiar with Java, and now after 10 + years it says I know Java. If you’ve only been working for a year…

I’ve been there before and I feel like I know everything and I don’t know where to go. Now that I think about it, I don’t understand it. Back to supplement the foundation, how simple examples are tested, thinking about the implementation principle, check the corresponding JDK code, after half a year to feel the qualitative change, just feel Java is really interesting!

It’s absolutely true that the more you know, the more you don’t know!

If you’ve been working for a year, chances are you don’t even know how to use ‘wait’ or ‘notify’. Refuses to accept? Wait and notify blockQueue

Add some useful information and tell me how I learned, just a little bit about data structures:

Let’s start with lists and maps. Arraylist and LinkedList are the most basic. Let’s take them as examples and look at their parent class and interface implementation. ArrayList inherits AbstractList, LinkedList inherits AbstractSequentialList, AbstractSequentialList inherits AbstractList, AbstractSequentialList: AbstractSequentialList: AbstractSequentialList: AbstractSequentialList: AbstractSequentialList: AbstractSequentialList: AbstractSequentialList: AbstractSequentialList: AbstractSequentialList: AbstractSequentialList: AbstractSequentialList: AbstractSequentialList

AbstractList implements the List interface. There are no new methods, so just look at the List methods. For each method, read the API description and test it again and again. There’s nothing pretty about add and remove, but focus on methods that you’re not familiar with.

The Cloneable/Serializable interface implements RandomAccess. Arraylist implements RandomAccess (no method). LinkedList implements a Deque. RandomAccess can be accessed using the get method, which is fast. If you are a LinkedList and use get, you will find that it is extremely slow. Deque explains the implementation of a bidirectional queue, in view of Dueue’s various methods to learn about all its features.

ArrayList has an initialCapacity parameter of type int. LinkedList does not. Think about why. Next you’ll see that the constructors of data structures with arrays have a capacity parameter (e.g., HashMap), which you’ll find useful. Dig a little deeper and you’ll see that ArrayList has a capacity concept…

At this point you should have your own summary:

A. ArrayList is implemented using arrays. It needs to initialize the capacity. If the capacity is insufficient, the capacity will be expanded.

B. Arraylists can be accessed randomly with get, and performance is fast. Linkedlists are slower with GET, and large data volumes should be avoided.

C. LinkedList implements a two-way queue, making it easy to add and delete data at the beginning and end.

D. Use listIterator when iterating through and making changes. Don’t fool around with 2 lists.

To this step is the entry, I dare to say their entry.

Want to work on it or are genuinely interested in it. You can ask me for some basic learning videos, Q number: 3300863615, this is free, I hope students don’t take it for granted when looking for me, after all, it is my efforts, I hope you really want to learn Java heart, I will do my best to help you become an excellent programmer.

Q plus I have the following requirements, do not disturb the substandard:

1. I majored in Java in college, but I was frustrated in the interview after graduation and could not find a suitable job

2. I have been in the company for a long time and now I am comfortable, but I hit a wall in the interview when I change my job. Need to study in a short time, job-hopping to get a high salary

3. After attending the offline training, I have not mastered the knowledge deeply enough, and it is difficult to find employment. I want to further my study

4, already in the Java related departments work on the job, on their own career planning is not clear, dawdle

5, have a certain C language foundation, contact with Java development, want to change careers

Do not disturb the trumpet, do not like to add

Then share a mind map, this stage is suitable for a year of work experience learning map:


The time that the interview hates a little person most opinionated: “this I don’t know, but I surf the net to check once knew!” You $? You didn’t even know it existed. You’d look it up?

I just want you to remember that the simplest foundation is the most important. I don’t want me to ask what map there is in the interview and only answer hashMap and Hashtable which I have known since I graduated from college… Author: Xiao Feng is light