Programmer Think

The iterator pattern is defined by providing a way to sequentially access the elements in an aggregate object without exposing the internal representation in the aggregate object. The iterator pattern is designed for the "access" of aggregate objects (arrays, collections, linked lists). Aggregate objects are traversed by defining diff ...

jvm runtime data area Overview The memory managed by java virtual machine will be divided into several areas when running. These areas have their own purposes, creation and destruction time. Some are created with the start of virtual machine process, and some are created and destroyed with the start and end of user thread. According to the vi ...

Method call For virtual machines, method invocation is not only to execute a method, but also to determine the target method to be executed. For example, in the case of replication, it is necessary to know whether to call the method of the parent class or the method of the child class. In the case of overloading, select one of multiple methods ...

Dear friends, when we create a new object, how is the object produced? Let's talk about the object generation process and memory allocation mechanism. We can talk about it during the interview, which is definitely a bonus. 1. Check when loading class During the execution of the virtual machine, Execute to new keyword (new keyword, object clo ...

1. Flow chart of loading classes in java.Main steps:Load: find the bytecode file on the hard disk and read it through IO. It will be loaded only when the class is used. For example, call the main() method and new object of the class. In the loading stage, a java.lang.Class object representing the class will be generated in memory as the access ...

Understanding GC Log is not easy, at least for most technicians. After all, for this thing, we need to have an in-depth understanding of the working principle of the Java virtual machine and the memory usage of the application. In this article, we will skip the analysis of the application because it is different from the application of th ...

Start with SimpleDateFormat Let's first look at an example. When 20 threads are created, one thing is done in the thread, that is, the conversion time public class ThreadLoaclExample { //Non thread safe private static final SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); public static Date parse(String strDat ...

This article is compiled and published by jiumo (Ma Zhi), chief lecturer of HeapDump performance communityChapter 1 - about the Java virtual machine HotSpot, the opening point is simpleStarting with the Java runtime, this article covers some simple contents. How is the main() method in our main class called by the Java virtual machine? Some met ...

1. What is the object termination mechanism? The Java language provides an object finalization mechanism to allow developers to provide custom processing logic before objects are destroyedWhen the garbage collector finds that no reference points to an object, it will clear the object in the garbage collection. Before the garbage collector ...

Soft reference test Test background Test environment: ​ jdk8 ​ windows garbage collector The default JVM parameter used by the command line viewer through PrintCommandLineFlags does not have UseParallelGC: xxx>java -XX:+PrintCommandLineFlags -version -XX:InitialHeapSize=16777216 -XX:MaxHeapSize=268435456 -XX:+PrintCommandLineFlags - ...