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I. overview Singleton pattern is a relatively simple and common design pattern in design pattern, but it is also a very classic high-frequency interview question. I believe there are still many people hanging here during the interview. This article mainly reviews the singleton pattern, recording its application scenarios, common writing, debugg ...

In the process of time maneuvering, judging by adding time stamp to the program, when inquiring HBase in batches, there will be some data inquiry time more than 8s, which is definitely unacceptable. Looking at hbase's logs, we can find the reasons. There are similar logs'GC pool'. It is speculated th ...

I. overview CAS, Compare And Swap, that is, compare and exchange. When Doug Lea is implementing synchronous components, CAS technology is used extensively and Java multi-threaded concurrent operation is implemented artificially. The whole AQS synchronization component, Atomic atom class operation, ...

Preface I believe that many senior and middle-level students in JAVA will often encounter an interview question during the interview.How do you tune and locate JVM problems in your work? In fact, if the number of users is small and your code is normal, how can we accumulate experience in this field unless we really encounter few problems relate ...

Online Problem Resolver Arthas BTrace was introduced before. The use of BTrace, an online problem solving tool It's also an online problem sorter.They are all artifacts, but today this is also very powerful. It's hard to say if it's more powerful, but it's very simple to use.If you're using BTrace, you need to write the probing script in advanc ...

When I study selenium 2 java, I have a function, which needs to test paging, 20 data per page. It's too troublesome to add one by one. The key is to add more than ten data to each page. I simply write a method to automatically add one of my high school grades. Share as follows: //Add High School Achievements public static void addRecord(WebDri ...

1. Method overload 1. Also known as overload 2. Method overload usage scenarios When functionality is similar, try to keep method names the same as possible (but when functionality is different or different, method names are as different as possible) 3. After what conditions are met, method overload can be constituted (1) in the same class ...

The concept of multithreading Modern operating systems can perform multiple tasks, i.e. they alternate multiple tasks in turn (as our users seem to be doing multiple tasks at the same time). process A task in a computer is called a process. So ...

The core of Start component development is the annotation order of automatic annotation classes, that is, annotation according to conditions. First, let's understand the @Configuration, @Value, @Bean annotations Take the DataSourceAutoConfiguration c ...

Downstairs of an office building on Dawang Road. Ape A: When we worked in our company, we ran a lot of data processing tasks in the middle of the night, and then the program often crashed. Me: Oh? How to deal with that? Ape A: There was some water in the architecture at that time. It said that we should adjust the ratio of "Eden" to ...