core java volume 1

Do you know the 21 core technical points of Java ?, Java 21 core technical points The purpose of this article is to summarize some of my experiences in using java over the years, mainly related to some basic java knowledge points,

the actual running situation after I adjust. num-executors Settings Num-executors from the original 30 to the current 56 (for convenience can be divisible by 8 slave, so set 56) first processing decompression strategy Limit the amount of data that is processed for the first time because the cold boot causes memory usage to be too large for the first time the job is started Spark.streaming.backpressure.enabled=true spark.streaming.backpressure.initialrate=200 2.x Message Queuing bug avoidance

One day, when I was restricted by many secular rules and could not do what many normal people could do, I suddenly felt: people should not have come to this world! Since we fell into the ground, we have been destined to suffer a lot in our life... There is always no proper balance between breaking rules and conforming rules. I will still choose to stick to the rules when I think that fox, the female killer in the movie "Assassin's League" (also known as the wanted order), will eventually end the

TCP/IP protocol details volume 1 Study Notes series 3-IP Routing Chapter 9 IP routing This chapter describes the basis of the TCP/IP protocol cluster. IP routing ensures that the correct transmission path can be found for the datagram. If it cannot be found, the sender will be notified of a failure to issue the message. The information used in the route finding process is maintained in two ways: each host m

Java Core Data Structure summary, java Core Data Structure JDK provides a Set of major data structures, such as List, Set, and Map. These structures are inherited from the java. util. collection interface. List Interface List has three different implementations. ArrayList

-doc directory. To view a document as text, you can use the following command: # git help If you want to query the documentation for the Git-checkout command, you can use the following command:# git Help git-checkoutIf you want to see a document in HTML format, you need to use the following command:# git help-w git-checkoutSubmission and acquisition of source code(1) Create repository: Git IIT(2) Submit the file to the local repository: git commit(3)

Android is a very good embedded operating system, Android system architecture is divided into 4 layers, the first layer of the Linux kernel, this layer mainly includes Linux drivers and memory management, process management, power management and other programs. and different Android versions of the driver may not be universal. The second layer is the C + + code base, which consists primarily of code libraries written in C + + (. So files under Linux), and also includes the runtime (runtime) of t

Use git to download two sets of source code, one set is the Android source code, one set is the Linux kernel source code. Since Android porting is primarily a migration of the Linux kernel, and the Linux kernel porting is primarily a Linux-driven migration, in order to develop and test Linux drivers, the Ubuntu Linux Build two sets of development environments: Android application development environment and Linux kernel development environment.First, download, pre-compile, and test the Android s

interfaces (multicast, broadcast, or anycast addresses). Each interface has a minimum of 32-bit IPV4 addresses, and there are typically several 128-bit IPV6 addresses.Both IPV4 and IPV6 support address formats that point to multiple network interfaces at the same time. IPV4 supports broadcast addresses and multicast addresses, but IPV6 only supports multicast addresses. Broadcasts allow one person to communicate with everyone, while multicast allows one person to communicate with multiple peopl

String is one of the core classes in java programming language. It is widely used and widely used.But do you know what is the direct string volume? Do you know there is a string resident pool? The string resident pool can be used to cache the direct string volume. What is a direct