Factory Design Pattern or Factory Method Design Pattern. It is a widely used and easy to understand design pattern. It is an effortless but effective way to hide the complexity of object creation. That’s why it belongs to the creation pattern category. Prerequisites for understanding the Factory Design Pattern Before you can understand what the Factory Design Pattern is, you need to know what superclasses superclasses and subclasses subclasses are. If you already know, you can skip to this section
The latest Java 19 two major features revealed
JDK 18/Java 18 was released last month, and JDK 19 is scheduled to be released in September this year, so before many developers can use Java 18, two of the latest target features about Java 19 have been revealed. There are two official features that will be released in the next version. One is the Vector API, and the other is the porting of the JDK to RISC-V. The former Vector API is an API that expresses vector computation and will be incubated for the fourth time in the next Java release; the latter proposed feature is the porting of the JDK to the open source Linux/RISC-V instruction set architecture (ISA).
10 Best Practices for Building Java Images
Do you want to build a Java application and run it in Docker? Do you know what the best practices are for building Java containers with Docker? In the following quick checklist, I’ll provide you with best practices for building production-grade Java containers designed to optimize and secure Docker images to be put into production environments. Building a simple Java container image Let’s start with a simple Dockerfile. When building a Java container, we often have something like the following.
Zero-copy technology and its application in Java
1 Preface Some time ago, I was involved in locating a problem with Tomcat that involved a sendfile system call. I suddenly thought of some of my previous experience with Java, and knew that there was a lot of open source software in the Java space that applied zero-copy to improve its performance, so I came up with this article. Look at these familiar software, have you ever understood the technical points behind their application:
Java Valhalla Project
Introduction In this article, we’ll cover the Valhalla project - the reasons for its history, the current state of development, and what it has brought to everyday Java developers since its release. Motivation and reasons. The Valhalla Project Brian Goetz, Oracle’s Java language architect, said in a talk that one of the main motivations for the Valhalla Project was the desire to adapt the Java language and runtime to modern hardware.
A few suggestions to improve the performance of regular expressions
Why is regular expression efficiency important? While well-written regular expressions can be very effective, poorly written regular expressions can take a long time to run and can significantly slow down a system. It is quite possible to write a regular expression that takes hours or days to complete, and it is even possible to write a regular expression that will not complete within the lifetime of the universe because it runs against a medium-sized string.
Java7 End of Life Cycle
Java SE 7, a nearly 11-year-old version of the Java standard, is coming to the end of its life cycle and Oracle will officially discontinue extended support for it at the end of July 2022. With official extension support is discontinued, Java 7 will enter a Sustaining Support model as defined by the Oracle Lifetime Support Policy. Oracle will no longer provide patch updates, bug or security fixes, or feature implementations.
JDK 19 feature set freeze: Java 19 has only 7 new features
Introduction From the Overview page of JDK 19, it appears that JDK 19 is in the Rampdown Phase Two, the entire feature set has been frozen and no further changes will be made to the JEP. Java 19 has only 7 new features. 405: Record Patterns (Preview) Record Patterns 422: Linux/RISC-V Port Linux/RISC-V porting 424: Foreign Function & Memory API (Preview) External Function and Memory API 425: Virtual Threads (Preview) Virtual Threads 426: Vector API (Fourth Incubator) Vector API 427: Pattern Matching for switch (Third Preview) Switch Pattern Matching 428: Structured Concurrency (Incubator) Structured Concurrency The following is a short description of the new features.
Introduction to the Range function in Java
Introduction In Java, the Range method is available in both the IntStream and LongStream classes. In the IntStream class it helps to return the sequential value of the IntStream in the range of function parameters. In this method, startInclusive(inclusive) and endExclusive(exclusive) are the two parameters used with the incremental step which, as mentioned before, will include the start value and exclude the end value. In the case of LongStream, the only difference is the addition of the LongStream value.
HttpServletRequest getParameter() missing parameter problem
Background Implemented a basic component can intercept all http requests, the request header/parameter/body/response, etc. for printout. Here the most critical and most difficult to deal with is the output of the body, because the transmission of characters in the body is obtained through the HttpServletRequest byte stream getInputStream (); and this byte stream does not exist after reading once. For example, the use of open source frameworks such as Spring some links have been intercepted to read the input stream, that after our custom interceptor to intercept the print body, the InputStream has no bytes … The implementation of the idea is not difficult, is their own inheritance to achieve HttpServletRequestWrapper, a copy of the body to save a good, and then in the Filter chain transfer can be.
Nuclear-grade Log4j vulnerabilities remain prevalent and have ongoing impact
Log4j “nuclear-grade” vulnerability Log4Shell may affect the world forever. The U.S. Department of Homeland Security (DHS) Cybersecurity Review Board (CSRB) recently released its investigative report in response to last year’s Log4Shell vulnerability. The CSRB is an agency established by DHS only this February to investigate major cybersecurity incidents and provide reports containing recommendations to enhance the nation’s cybersecurity. The CSRB’s first investigation was into the “nuclear-grade” vulnerability that erupted in Log4j last year.
Java Date Timestamp Date Comparison Pitfalls
Scenario reenactment In the mysql database (innodb engine) tab table has a createAt field of type datetime(6) precise to milliseconds.Of course we know that mysql’s date field is only accurate to the second level by default, if you want to millisecond subtlety can be defined as datetime(6), from version 5.6.4 onwards support business interface A through the ORM framework to deposit a record in the table, here createAt deposit2016-04-13 15:20:39.152
StackOverflowError errors in Java
Introduction StackOverflowError can be annoying for Java developers as it is one of the most common runtime errors we may encounter. In this article, we will learn how this error occurs by looking at various code examples and how to handle it. Stack Frames and StackOverflowerError Occur Let’s start with the basics. When a method is called, a new stack frame is created on the call stack. This stack frame contains the parameters of the called method, its local variables and the return address of the method, i.
Jump table implementation in Java
Introduction Jump table is a data structure for storing a sorted list of elements with the help of a linked table hierarchy connected to a subsequence of elements. Jump table allows to handle item lookups in an efficient way. A jump table is a probabilistic data structure, which means that it skips several elements of the entire list, hence the name. We can think of a jump table as an extended version of a linked table.
The difference between the delete() method and deleteOnExit() method in Java.io.
delete () method Deletes a file directly when the delete () method is called, regardless of whether the file exists or not, and executes it as soon as it is called. deleteOnExit () method When the deleteOnExit () method is called, it is only equivalent to a declaration of deleteOnExit (), and the deleteOnExit () method is really called when the program is finished running and the JVM is terminated to achieve the delete operation.
Why do double floating point operations lose precision?
1. What is a floating point number? A floating point number is a type of data used by computers to represent decimals, using scientific notation. In java, double is a double-precision, 64-bit, floating-point number, and the default is 0.0d. float is a single-precision, 32-bit floating-point numbers, default is 0.0f. Storing in memory float sign bit (1 bit) exponent (8 bit) mantissa (23 bit) double sign bit (1 bit) exponent (11 bit) mantissa (52 bit)
Seven of the best Java testing frameworks
Java is one of the most popular programming languages today and is perennially in the top three of the most popular programming languages. A good java programmer cannot develop safer and more efficient code without knowledge of testing frameworks. One of the most important reasons for using these testing frameworks is to reduce the possibility of errors, increase development efficiency, and reduce development costs. In this article, we will introduce the most common testing frameworks used for Java testing.
Java Proxy Pattern Explained
1. Proxy Pattern The proxy pattern is a relatively well understood design pattern. Simply put we use a proxy object to replace access to the real object (real object), so that we can provide additional functional operations to extend the functionality of the target object without modifying the original target object. The main purpose of the proxy pattern is to extend the functionality of the target object, for example, you can add some custom operations before and after the execution of a method of the target object.
Java Geometry spatial geometry data processing applications
First understand a few basic concepts that help to understand the application scenario of this article Geographic Information System GIS GIS (Geographic Information System or Geo-Information system, GIS) is sometimes referred to as a “geographic information system”. It is a specific and very important spatial information system. It is in the [computer] hardware and software system support, the whole or part of the [Earth] surface (including the atmosphere) space in the relevant [geographic] distribution [data], [storage], [management], [computing], [analysis], [show]and [description] of the technical system
Java8 is going down? Jenkins announces support for Java 11 and above only
Jenkins, an open source Devops tool, announced: Starting with the June 28th release of Jenkins 2.357 and the upcoming September LTS release, Jenkins requires Java 11 as a minimum. Originally known as Hudson, Jenkins is a venerable continuous integration tool that has been in existence for over a decade. Since its inception in 2005, the Jenkins project has undergone several Java migrations. The current migration from Java 8 to Java 11 is consistent with the migration history in the Jenkins project.