From Java 8 to Java 11

Switching from Java 8 to Java 11 is more complicated than most updates. Here are some of my notes on the process.

Modules

Java 9 introduced one of the biggest changes in the history of Java modules. Much has been said on the subject, by other people. A key point is sometimes forgotten:

You do not need to modulate your code to update to Java 11.

In most cases, the code that runs in the class path will continue to run in Java 9 and later, where the modules will be completely ignored. This is terrible for library authors, but optimal for application developers.

So, my advice is to ignore the modules as much as you can when upgrading to Java 11. Transforming your application into Java modules can be a useful thing to consider in a few years when the free software dependencies really start adopting the modules. At the moment, trying to modularize is only painful, since few dependencies are modules.

(The main reason I found to modularize your application is to be able to use jlink to reduce the size of JDK.) But, in my opinion, you do not need to fully modulate to do this – just create a single jar – with dependencies with a simple no- requires no-exports module-info.)

Parties excluded from the JDK

Some parts of the JDK were removed. These were parts of Java EE and Corba that no longer fit the JDK or could be maintained elsewhere.

If you use Corba, then there is little that someone can do to help you. However, if you use the Java EE modules, the correction of the deleted code should be simple in most cases. You just have to add the appropriate Maven jars.

On the Java client side, things are more complicated with the removal of Java WebStart. Consider using Getdown or Update4Jinstead.

Unsafe and friends

Sun and Oracle have come to developers for years that do not use the sun.misc.Unsafe and other leading edge JDK APIs. For a long time, Java 9 was the launch where those classes disappeared. But that never really happened.

What you can get with Java 11, however, is a warning. This warning will only be printed once, on the first access to the restricted API. It is a useful reminder that your code, or a dependency, is doing something “impertinent” and will have to be corrected at some point.

What you will also discover is that Java 11 has several new APIs designed specifically to avoid the need to use Unsafee the friends. Make a priority to investigate these new APIs if you are using an “illegal” API. For example, Base64, MethodHandles.privateLookupIn, MethodHandles.Lookup.defineClass, StackWalker and Handles Variables.

Tools and Libraries

The modules and the new biannual launch cycle conspired to cause a real impact on the use of tools and libraries that developers use. Some projects were able to accompany. Some have fought. Some failed.

When updating to Java 11, an important task is to update all its dependencies to the latest version. If there is not a posting since Java 9 was released, then this dependency may need additional attention or testing. Make sure you have updated your IDE as well.

But it’s not just the dependencies of the applications that need to be updated, as well as Maven (and the Gradle too, but I do not know much about the Gradle). Most Maven plugins have changed major versions to v3.x, and upgrading Maven itself to v3.5.4 is also beneficial.

Unfortunately, the maven’s main equipment is very small, so there are still some errors / problems to solve. However, if your Maven construction is sensible and simple enough, it should usually be fine. But note that updating a plug-in from a v2.x to a v3.x can involve changes to the configuration in addition to those associated with the modules. For example, the Maven Javadoc plugin has changed the name of the argLine property.

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An important point to be observed is the way in which Maven operates with the modules. When the Maven compiler or surefire plugin finds a jar file that is modular (that is, with a module-info.class), you can place that jar in the module path instead of the class path. In this way, even if you want to run the application completely on the classpath, Maven can compile and test the code partially on the classpath and partly on the module path. At the moment, there is nothing that can be done about it.

Sometimes, your compilation will need some larger changes. For example, you will have to change the Findbugs for SpotBugs. And change the Coverage to JaCoCo.

These compilation changes may take some time – they did it for me. But the information available for a simple investigation on the web is increasing all the time.

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Summary

I have updated several Joda / ThreeTen projects to support Java 9 or later now. It was very painful. But that’s because, as the author of a library, I have to produce a jar file with module information that is built and executed in Java 8, 9, 10 and 11. (In fact, some of my jar files run in Java 6 and 7 too!)

Having made these migrations, my conclusion is that the pain is mainly in maintaining compatibility with Java 8. Moving an application to Java 11 should be simpler, because there is no need to get stuck in Java 8.

November 27, 2018 0

Java 101

A complete introduction for beginners to the Java platform

So, do you want to program in Java? This is great and you have come to the right place. The Java 101 series provides a self-guided introduction to Java programming, starting with the basics and covering all the main concepts you need to know to become a productive Java developer. This series is technical, with many code examples to help you understand the concepts as we go. I guess you already have some experience in programming, but not in Java.

This inaugural article presents the Java platform and explains the difference between its three editions: Java SE, Java EE and Java ME. You will also learn about the role of the Java virtual machine (JVM) in the implementation of Java applications. I’ll help you set up a Java Development Kit (JDK) on your system so you can develop and run Java programs, and start with the architecture of a typical Java application. Finally, you will learn how to compile and run a simple Java application.

What is Java?

You can think of Java as a general-purpose object-oriented language that looks a lot like C and C ++, but which is easier to use and allows you to create more robust programs. Unfortunately, this definition does not offer much information about Java. A more detailed definition of Sun Microsystems is as relevant today as it was in 2000:

Java is a simple computer language, object oriented, intelligent in network, interpreted, robust, secure, with neutral architecture, portable, high performance, multithread and dynamic.

We will consider each of these definitions separately:

Java is a simple language. Java was initially modeled after C and C ++, minus some potentially confusing resources. Pointers, multiple implementation inheritance and operator overload are some C / C ++ resources that are not part of Java. A non-mandatory feature in C / C ++, but essential for Java, is a garbage collection feature that automatically retrieves objects and arrays.
Java is an object-oriented language. The object-oriented Java approach allows developers to work on Java adaptation to solve a problem instead of forcing us to manipulate the problem to meet language restrictions. This is different from a structured language like C. For example, while Java allows you to focus on objects in the savings account, C requires that you think separately about the state of the savings account (such balance) and behaviors ( as deposit and drawing).
Java is a language with network knowledge. The extensive Java network library makes it easy to manage TCP / IP network protocols, such as HTTP (Hypertext Transfer Protocol) and FTP (File Transfer Protocol) and simplifies the task of making network connections. In addition, Java programs can access objects through a TCP / IP network, through resource locations (URLs), with the same ease with which they are accessed from the local file system.
Java is an interpreted language. At run time, a Java program runs indirectly on the underlying platform (such as Windows or Linux) through a virtual machine (which is a software representation of a hypothetical platform) and the associated execution environment. The virtual machine translates the bytecodes of the Java program (instructions and associated data) for specific instructions of the platform by means of interpretation. Interpretation is the act of discovering what a bytecode instruction means and then choosing equivalent “canned” platform-specific instructions to execute. The virtual machine then executes these platform-specific instructions.

The interpretation facilitates the debugging of defective Java programs, because there is more information at compile time available at runtime. The interpretation also makes it possible to delay the connection stage between the parts of a Java program until the execution time, which accelerates the development.

Java is a robust language. Java programs must be trusted because they are used in personal and mission-critical applications, from Blu-ray players to air navigation systems or air control. The language resources that help make Java robust include declarations, duplicate type checking at compile time and runtime (to avoid version incompatibility issues), true arrays with automatic boundary checking and pointer omission. (We will discuss all of these resources in detail later in this series.)

Another aspect of Java’s robustness is that loops must be controlled by Boolean expressions instead of integer expressions, where 0 is false and a non-zero value is true. For example, Java does not allow a loop in style C, such as while (x) x ++; because the loop cannot end where it is expected. Instead, you must explicitly provide a Boolean expression, such as while (x! = 10) x ++; (which means that the loop will run until x equals 10).

Java is a safe language. Java programs are used in network / distributed environments. Because Java programs can migrate and run across multiple platforms on a network, it is important to protect these platforms against malicious code that can spread viruses, steal credit card information, or execute other malicious acts. The characteristics of the Java language that support robustness (such as the omission of pointers) work with security features, such as the Java sandbox security model and public-key cryptography. Together, these resources prevent viruses and other dangerous codes from wreaking havoc on an unmanned platform.

In theory, Java is safe. In practice, several security vulnerabilities have been detected and explored. As a result, Sun Microsystems and Oracle now continue to release security updates.

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Java is a neutral language in architecture. Networks connect platforms with different architectures based on various microprocessors and operating systems. You can not expect Java to generate platform specific instructions and have those instructions “understood” by all types of platforms that are part of a network. Instead, Java generates platform-independent byte code instructions that are easy to interpret for each platform (through its JVM implementation).
Java is a portable language. The neutrality of architecture contributes to portability. However, there is more to Java portability than platform-independent byte code instructions. Consider that the sizes of integer types should not vary. For example, the 32-bit integer type should always be signed and occupy 32 bits, regardless of where the 32-bit integer is processed (for example, a platform with 16-bit registers, a platform with 32-bit registers or a table platform with 64-bit registers). Java libraries also contribute to portability. When necessary, they provide types that connect Java code to platform-specific resources in the most portable manner possible.

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Java is a high performance language. The interpretation produces a level of performance that is generally more than adequate. For high-performance application scenarios, Java uses just-in-time compilation, which analyzes interpreted bytecode instruction sequences and compiles frequently interpreted instruction sequences for platform-specific instructions. Subsequent attempts to interpret these sequences of bytecode instructions result in the execution of equivalent platform-specific instructions, resulting in increased performance.
Java is a multiprocess language. To improve the performance of programs that must perform several tasks at the same time, Java supports the concept of chained execution. For example, a program that manages a graphical user interface (GUI) while waiting for the input of a network connection uses another thread to execute the wait instead of using the standard GUI thread for the two tasks. This keeps the GUI responsive. The Java synchronization primitives allow the threads to securely communicate data with each other without corrupting the data. (See programming chained in Java, discussed elsewhere in the Java 101 series).
Java is a dynamic language. Because interconnections between program code and libraries occur dynamically at runtime, it is not necessary to explicitly link them. As a result, when a program or one of its libraries evolves (for example, for error correction or performance improvement), a developer only has to distribute the updated program or library. Although dynamic behavior produces less code to distribute when a version change occurs, this distribution policy can also lead to version conflicts. For example, a developer removes a class type from a library or renames it. When a company distributes the updated library, existing programs that depend on the type of class will fail. To greatly reduce this problem, Java supports a type of interface, which is like a contract between two parties.

November 26, 2018 0

Introduction to the Java Development Kit

Introduction

The Java Development Kit (JDK) is one of the three main technology packages used in Java programming, together with the JVM (Java Virtual Machine) and the JRE (Java Runtime Environment). It is important to differentiate these three technologies, as well as to understand how they are connected:

The JVM is the component of the Java platform that runs programs.
The JRE is the part of the Java disk that creates the JVM.
The JDK allows developers to create Java programs that can be executed and executed by JVM and JRE.

Beginning Java developers often confuse the Java Development Kit and the Java Runtime Environment. The distinction is that the JDK is a toolkit for Java-based software development, while the JRE is a suite of tools for executing Java code.

The JRE can be used as a separate component to run Java programs, but it is also part of the JDK. The JDK requires a JRE because running Java programs is part of their development.

Technical definition: The JDK is an implementation of the Java platform specification, including the compiler and the class libraries.
Definition of every day: JDK is a software package that downloads to create Java-based applications.

Start with the JDK

Obtaining Java configuration in your development environment is as easy as downloading a JDK and adding it to your classpath. When you download your JDK, you will need to select the Java version you want to use. Java 8 is the most commonly used version, but, so far, Java 10 is the most recent version. Java maintains compatibility with previous versions, so we will download the latest version.

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JDK packages

In addition to choosing your version of Java, you will also have to select a Java package. The packages are Java development kits that are directed to different types of development. The available packages are Java Enterprise Edition (Java EE), Java Standard Edition (Java SE) and Java Mobile Edition (Java ME).

Beginning developers are sometimes not sure which package is right for their project. In general, each JDK version contains Java SE. If you download the Java EE or Java ME, you will get the standard edition with it. For example, the Jave EE is the standard platform with additional tools useful for the development of enterprise applications, such as Enterprise JavaBeans or support for Relational Object Mapping.

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It is also not difficult to change to a different JDK in the future if you find that you need it. Do not worry much about choosing the correct version of Java and the JDK package when you have just started.

November 24, 2018 0

Microservice Logging: Challenges and Advantages

One of the main developments in software design and delivery in recent years has been a movement of monolithic applications for microservices. One of the critical points that I have seen in several microservice applications is the registry. There are some unique challenges with the microsion log that need to be resolved. In this article, we will see how we can do the registration in a microservice as painless as in a monolith.

What is a microservice?

There are many definitions of microservices out there, but that’s the one I like.

Microservices: A high-level software design that favors small and weakly connected services that maintain data autonomy and are independently implantable.

Breaking this up using microinsurance is a high level decision. It is not a standard that applies only to a part of your application, but it must be a global decision. By using microservices, we create several smaller applications with very limited functionality. For example, we can have a service whose responsibility is to act as a container to chat with an external API. Services must be weakly connected: there are no direct connections between services or cross-talk between services. Services must have their own data storage solution that is not shared with another service. This means absolutely no integration at the database level! Finally, there should be no dependencies between the services at the time of implementation.

Setting limits between services in a microsystem cluster is a difficult problem. There are many ideas around it, but most of them revolve around domain-oriented design.

Different challenges of a monolith

Although there are many advantages in a microservice approach, there are also disadvantages. The monoliths are implemented as a single entity in one or more servers, each of which obtains the same code. This unique implantation is a curse and a blessing. Unique implementations mean that you have fewer moving parts in the creation and deployment pipeline. There are no concerns about data transport between various applications or discovering the limits for these applications. The most important advantage for this article is that the registration in the registry resides in only one location.

The log is a perfect example of a transversal concern: code that needs to cover several modules at different levels of the code base. When we divide our application into silos, the record is also divided into all services.

A single logging technology

A much discussed benefit of microinsurance is that each service can be written using appropriate technology. A component that does a lot of mathematics may not be as efficient written in JavaScript as in Go. Microservices allow you to select a technology that best suits each component. Generally, each microservice is built by a team specialized in the technology used in that service. Reinforcing a single data logging technology is a challenge to the microservice mentality. However, this is a time when it is justified to go back in academic perfection in favor of pragmatism.

A shared logging implementation for every service

A single registration technology provides us with a location for the records, regardless of which service originates the registration message. If we are trying to find a network problem, we do not want to have to go through several log files located all over the place to see what services have been affected. Ideally, we want to have a one-stop-shop that allows searching, classifying and designing registration information for several dozens of services. The technologies that allow this, registry aggregators, tend to have connectors for several languages. For example, Stackify Retrace has connectors for Java, .NET, PHP, Ruby and Node.js out of the box, as well as a Restful API that unlocks almost all other languages.

The errors can cover several microservices, so the registry as our best tool to track errors must also cover them.

A logging technology which allows queries

A single user interaction in a microsystem architecture can encompass many services. Being able to accompany a user interaction is much easier if you have a registration tool that allows you to use an advanced query language to search, design and add. The registration in aggregate can also be very useful. Queries like this one are super-valuable: “what percentage of requests for X service results in errors?”, Or “what time of day do we see the biggest load on the system”, or even “what is the average time that an application spend? in the X service. ”

Naturally, there are many registry aggregators out there, and choosing one that has an advanced query language is a good differential. Another aspect to consider is how easy it is to see the data after writing a query for them. A good chart will give you background information that are difficult to analyze from a record message.

Next, there is an example of a Retrace panel showing several important metrics, some of which are extracted from record searches.

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Use a correlation identifier

When a client contacts you with a problem you had in your application, it is very good to be able to quickly find what has gone wrong. One method to do this in a micro security application is to include a correlation or transaction ID in each message. Fill this field with an ID removed from the initial event. Consider a scenario in which a user creates an account. This can trigger actions in the user’s service, in the customer loyalty service and in the billing service.

By having a unique identifier that is disconnected by each of these services while processing a message, it is easy to find the creation flow of the user. All that is needed is to pop the unique identifier in the search engine of the record aggregator and get all the registration messages related to that transaction. You can even present the user with that correlation ID, if something goes wrong, so you have a reference number to quote when talking to your support organization; This is even more useful if you are the support organization.

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Include a lot of information

It is much more common that you want to have more information recorded than less. Obviously, there are some performance and storage considerations in relation to over-registration, but very small registration can lose the main information forever. Including context information in your log messages increases the chances that you can track problems. For example, it usually improves my log messages with information such as:

service name that generates the registration message
Correlation ID
username that triggered the action
machine name or container id
date of receipt of the message in UTC
date of sending the message in UTC
entire body of the drive message

Carefully consider what information would be useful in debugging problems and you would be wrong to include too much. If you are using a registration structure that supports structured registration (which is excellent), you can place all this information in the properties of the logging message and not overload your actual messages.

November 23, 2018 0

Java EE Overview

In this article, you will find information about the history of the Java EE ecosystem: where it came from and how it has changed in recent decades. You will discover the main milestones in its development, from J2EE 1.2 to its current incarnation Java EE 7, and we will see in the future what Java EE 8 has reserved.

You will discover how to get involved with the development of the platform itself and how to enter JCP.org to make an even greater contribution. Find out about the Java EE Guardians and how you can support the development and growth of the platform.

What is Java EE?

Java EE consists of a set of more than 28 specifications and a runtime environment. It is a superset of the Java SE platform. This means that Java EE components can take full advantage of all Java SE APIs.

This set of APIs creates multilayer applications based on standard components and implements in different containers, offering a variety of services. It is not only used to develop monolithic application structures, but also structured applications of microsystems. More information about Java EE and microservices checking Java EE and Microservices in 2016? You are interested in the development of tip in the space of microservices with respect to Java EE? Next, visit the Eclipse Microprofile project website.

The Java EE programming model has annotations to specify settings instead of XML description files and uses the configuration convention to help you start using the least possible ceremony.

It has its own contextually conscious dependency injection structure at the center of its programming model.

History of Enterprise Java

In 1998, the first incarnation of Enterprise Java was launched, but then important technologies soon joined the mix, such as Servlets, Messaging and Enterprise Java Beans.

These technologies still exist on the Enterprise platform today, but in a much more advanced and complete way.

In the following years, he developed a programming model that was difficult to use and very complicated. All this changed in the fifth edition, which saw a radical change of the XML configuration towards the notes and convention about the configuration.

The new programming model has been substantially simplified. Annotations replace the XML description files, the configuration convention replaces the tedious manual configuration, and dependency injection hides the creation and search for resources. Resources are created and injected into injection points marked by annotations such as @Inject. Therefore, all you need is a POJO that meets the conditions of the managed beans specification, JSR 299 and, depending on the annotation used, it will become an EJB, Servlet, Singleton or RESTful Web service.

The platform continued to grow, but at a much slower pace. To each new version, it becomes more friendly to the programmer and the number of APIs grew to reach 28+, above only a handful of five APIs in 1999.

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What comes in Java EE 8?

Oracle is moving the focus of Java EE to microservices and the cloud, and the next version of Java EE will include the APIs that complement this new address.

As well as advances in some established technologies, such as Bean Validation, Context Injection and Dependency, JavaServer Faces, JAX-RS (RESTful web services), JSON-Processing and Servlets, there will be two new APIs.

JSON-binding, a dedicated security API and security API for Java EE, designed to standardize security.

The Java EE 9 will see even more APIs designed for the development of microsis and cloud-based applications.

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Java Community Process (JCP)

The development of the Java EE platform occurs through the Java Community Process (JCP), responsible for all Java technologies.

The group of experts consists of interested parties who created Java specification requests (JSR) to define the various Java EE technologies. All done in cooperation with the international community of Java developers.

The work of the Java community under the JCP program helps to guarantee the stability and compatibility standards between Java technology platforms.

Anyone can review and comment on draft specifications and JSR proposals, as well as read the JCP blog. Anyone can register as user

Anyone can review and comment on draft specifications and JSR proposals, as well as read the JCP blog. Anyone can register as a user of the site and can be authorized as a member of the Collaborator or the Group of Experts. You can become a JCP member and make an even greater contribution. Go to the link to discover more.

November 22, 2018 0

6 Types of ROI for APM (Application Performance Management Tools)

6 Types of ROI for APM (Application Performance Management Tools)

It has been said that almost all companies are now a software company in some way or another. This means that the reliability and performance of your software applications are critical to your success. Unfortunately, many application performance management (APM) tools have been very expensive and only target large companies.

The price of the APM for 20 servers can vary from US $ 500 to US $ 6,000 per month. Some providers also require that they be paid annually. It is common to hear from customers who may experience our product, Retrace, for a few hundred dollars a month or to pay another supplier of US $ 25,000 and who are stuck in an annual contract.

APM solutions can be accessible and have an invaluable return on investment (ROI) if they are used to their full potential. In this article, we will discuss some of the main benefits of APM and how they provide excellent ROI.

Examples of APM ROI and other benefits

Increase in developer productivity

Software developers are expensive. They are also a highly limited resource in today’s economy. It is important to keep them working on innovating new products that can expand their businesses. The development tools that make them more productive are very valuable.

Solving production problems can be very difficult and delayed. APM tools are designed to help developers quickly identify application problems.

If the APM can save its developers for a few hours a month, it’s easy to see how quickly it pays. The ZeroTurnaround developer’s productivity report showed that the average developer spends at least a few hours a week firefighting production problems.

Prevention of application problems

The sooner an application problem is identified and corrected in the development life cycle, the less time and money will be necessary. In a perfect world, we would all like to find all the problems of the application while the developers are writing the code or the quality control.

Tools like Prefix and Retrace can do exactly that. The prefix is free and the Retrace is only US $ 15 per month per server in quality control. It is very difficult not to justify these costs if it can help identify problems before they reach production.

It is easy to understand that finding errors when writing code or in quality control is much easier to fix than in production. A simple production error can also cause tens or hundreds of support problems with your customers. The last thing you want to do is overload your support or sales teams with the management of boring customers.

The cost of downtime

Another day I ordered pizza at the Pizza Hut site. If your website was slow or down for any reason, you could easily order pizza from a dozen other companies. Every minute that your site is down has a big impact on your sales for the day and your bottom line.

Delta Airlines had an interruption of 5 hours in August 2016. Problems with the computer forced us to cancel about 2,000 flights. They reported that it cost them 150 million dollars. British Airways and Southwest also had disruptions last year that caused them a lot of money.

Proactive application monitoring can help identify problems before they become worse. To find slow SQL queries to identify high volume requests that must be optimized.

Being able to quickly identify the root cause of a problem can drastically reduce the average repair time (MTTR).

Performance as a resource

Keep in mind that performance is also a feature of your application. Users love software fast. This creates a larger overall feel for your product. It can be difficult to quantify, but it helps in conversions and customer retention.

Slow performance can affect your profitability. Amazon found every 100ms of latency cost them 1% in sales. We can all relate to trying to buy something online and stop because it was taking too long.

Children may be screaming, it’s time to go to dinner or some other reason. Sometimes, we tell ourselves that we will see later when we have more time. Many times we do not remember or spend our money on something else. “I almost bought one of those” is the last thing any retailer wants to hear.

One of our clients offers small loans for their clients online. Your site was taking 10 to 15 seconds to load and I could not understand why. They managed to use the Retrace to identify that the caching did not work correctly.After applying the fix, they were immediately able to see a substantial increase in business.

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5. Reducing Hosting Costs

APM products are very useful for measuring the performance of your applications and help identify opportunities for improvement. A SQL query fits here, some code refactoring, and you can reduce your hosting costs through some optimizations.

For example, in Stackify, we had an application that worked on about 20 servers. Using the Retrace to identify possible performance optimizations, we managed to refact some codes and reduce the number of servers by 50%. This simple change saved us $ 2,000 a month.

APM tools can help you understand how your applications use SQL databases, Elasticsearch, Web services and much more. We’ve heard all the time from customers who had no idea how many SQL queries the application runs or how slow the queries were. A bit of performance tuning around application dependencies can improve overall performance and allow you to reduce these dependencies.

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SLA requirements

Many B2B companies have service level agreements (SLAs) with their partners. These agreements generally have clear written penalties if the software is not online and works properly.

A brief interruption of Amazon AWS in February 2017 will cost you 2% of your total income due to the SLA credits. A small interruption of 5 hours would probably cost millions in revenue. Their interruptions caused problems for many customers, including Apple, Adobe and Netflix.

Amazon would have to reimburse 10-30% in service credits. Many providers offer service credits based on how poorly the SLA has been lost. Here is an example of a table that defines how an infraction in the SLA is treated.

Conclusion

In this article, we discuss some of the ways in which APM tools provide very high ROI. They can help with developer productivity, avoid problems with applications, reduce hosting costs, optimize performance and avoid costly downtime.

More importantly, APM tools can help you sleep at night.

They help you proactively monitor the performance of your applications 24 hours a day. They are also there when you need to get in and quickly solve a problem.

The price and functionality of APM tools vary widely. See our list of APM’s top 10 critical resources. You may also want to read about the accessibility of APM products and how they are accessible to smaller companies.

Application monitoring tools do not have to be too expensive. The goal of Stackify from the first day was to create an affordable and holistic suite of application monitoring tools. Retrace combines lightweight code profile, application errors, logs, metrics and much more in an easy to use tool for developers.

November 21, 2018 0

The profile of Java Profiler

Debugging performance problems in production can be a pain and, in some cases, impossible without the right tools. Java profile creators have always existed, but the projectors that most developers think are just one type – in fact, there are three:

Standard JVM profiles that track all the details of the JVM (CPU, chaining, memory, garbage collection, etc.).
Light profilers that emphasize its application with a little abstraction.
Application performance management (APM) tools used to monitor live applications in production environments.

Standard JVM profiles

A standard Java profiler certainly provides most of the data, but not necessarily the most useful information. This depends on the type of debugging task. These profiler will track all method calls and memory usage, allowing a developer to immerse themselves in the call structure at any angle they choose.

Lightweight transaction profiles in Java

The creators of light profiles adopt a different approach when tracking their application, injecting themselves directly into the code. Aspect Profilers uses aspect-oriented programming (AOP) to inject code at the beginning and end of the specified methods. The Java Agent profile creators use the Java Instrumentation API to inject code into their application.

Under Overload, Creating Java JVM Profile in Production (APM)

All profilers have been optimal for development so far, but monitoring how your system works in production is critical. Production is always a different landscape – the development and preparation configurations usually do not have the same data sets and load.

Java APM tools generally use the Java Agent profile creator method, but with different instrumentation rules to allow execution without affecting production performance. The trick with these proflets is to provide the correct information in a smart way so as not to occupy the CPU cycles.

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Why are some Java profiles so expensive?

XRebel is a legal tool, but it costs US $ 365 per year. The Stackify Prefix is free and provides much of the same functionality.

The biggest problem with APM solutions is definitely its price. Traditionally, they are so expensive that only the largest companies can deal with them. It does not make much sense to spend $ 100 a month on a server in Azure or AWS and spend another $ 200 a month for a product like the new relic.

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The monitoring tools should not cost more than the servers! Both Prefix and Retrace have profile creation functionality and are incredibly accessible. The prefix is free for life and the Retrace is free in the first two weeks.

Applications for managing Java profiles and other Java tools, books, websites and blogs, YouTube channels, podcasts, events and LinkedIn can be found in our complete Java Developer’s Guide.

November 20, 2018 0

Introduction to the Java runtime environment

Together, the Java Development Kit (JDK), the Java Virtual Machine (JVM) and the Java Runtime Environment (JRE) form a powerful fragment of Java platform components to develop and execute Java applications. I have already presented the JDK and the JVM. In this quick tutorial, you will learn about the JRE, which is the runtime environment for Java.

In practice, a runtime environment is software developed to run other software. As the runtime environment for Java, the JRE contains the Java class libraries, the Java class loader, and the Java virtual machine. In this system:

• The class loader is responsible for correctly loading the classes and connecting them to the main Java class libraries.

• JVM is responsible for ensuring that Java applications have the necessary resources to run and run well on your device or cloud environment.

• The JRE is primarily a container for these other components and is responsible for orchestrating its activities.

What is a runtime environment?

A software program must be run and, for this, it needs an environment to run. The runtime environment loads class files and ensures that there is access to memory and other system resources to execute them. In the past, most software used the operating system (OS) as its runtime environment. The program worked inside the computer it was on, but it had operating system configurations for accessing resources. Resources in this case would be things like memory and program files and dependencies. Java Runtime Environment has changed all this, at least for Java programs.

The Java runtime environment

We can see the software as a series of layers that are located at the top of the system’s hardware. Each layer provides services that will be used (and needed) by the layers above it. Java Runtime Environment is a software layer that runs on a computer’s operating system, providing additional services specific to Java.

The JRE softens the diversity of operating systems, ensuring that Java programs can run on virtually any OS without modification. It also provides value-added services. Automatic memory management is one of the JRE’s most important services, ensuring that programmers do not need to manually control memory allocation and relocation.

In summary, the JRE is a kind of meta-operating system for Java programs. It is a classic example of abstraction, abstracting the underlying operating system into a consistent platform for running Java applications.

Java and JRE memory

Java memory consists of three components: the heap, the stack and the metapace (formerly called permgen).

• Metaspace is where Java keeps the immutable information of its program, as class definitions.

• Heap space is where Java maintains variable content.

• Stack space is where Java stores execution references and function variables.

Memory management in Java 8

Until Java 8, the metapace was known as permgen. In addition to being a much more legal name, the metaspace is a significant change in the way developers interact with Java’s memory space. Previously, use the java -XX: MaxPermSize command to monitor the size of the permgen space. From Java 8 below, Java automatically increases the size of the metaspace to accommodate the meta-needs of your program. Java 8 also introduced a new indicator, MaxMetaspaceSize, which can be used to limit the size of goals.

Heap space configuration

Heap space is the most dynamic part of the Java memory system. You can use the -Xms and -Xmx flags to inform Java of the size of the heap start and the size of the permission for it. Understanding how to adjust these indicators to specific program needs is an important aspect of memory management in Java. Ideally, the pile is sufficient to obtain the most efficient garbage collection. That is, you want to allow enough memory to allow the execution of the program, but you do not want it to be larger than necessary.

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Configuration of the stack space

The stack space is where function calls and variable references are routed. The stack space is the source of the second most notorious error in Java programming: the stack overflow exception (the first is the null pointer exception). The stack overflow exception indicates that you ran out of stack space because a lot of it was reserved. Normally, it receives a stack overflow when a method or method calls one another in a circular fashion, thus dedicating an increasing number of function calls to the stack.

You use the -Xss option to configure the initial size of the stack. The stack grows dynamically according to the needs of the program.

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Monitoring of Java applications

Although application monitoring is a function of JVM, the JRE provides configuration options, which are the baseline necessary for tracking. A variety of tools is available for monitoring Java applications, from the classic ones (such as the top Unix command) to sophisticated remote monitoring solutions, such as Oracle infrastructure monitoring.

Among these options are the creators of visual profiles, such as VisualVM, that allow you to inspect a running JVM. These tools allow you to track access points and memory leaks, as well as see the overall memory consumption in your system.

Conclusion

Java Runtime Environment is the disk program that loads Java applications so that the JVM runs. A JRE is included by default when you download the Java Development Kit, and each JRE includes the main Java class libraries, a Java class loader, and a Java virtual machine. It is useful to understand how JVM, JDK and JRE interact, especially to work in cloud and devops environments. In these environments, the JRE assumes a more important role in monitoring and configuration than in the traditional development of Java applications.

November 19, 2018 0

4 Types of Java Logs

Log is an important issue in software development, especially if you need to analyze errors and other unexpected events in your production environment. Implementing your registry usually seems easy. But, as you have probably experienced, the creation of log is much more complex than it seems. As an experienced developer, you should know the different Log structures available, the common pitfalls and best practices and, of course, the types of log files used in common deployment scenarios. In this article, I will focus on the last part. I’m going to talk about 4 different types of logs that you can find in almost every development or production environment.

Application Log

Let’s start with the most common type of Log: application log

Most developers think about that record when talking about the registry. The reason for this is simple. Your application produces this record. It contains all types of error messages, warnings or other events recorded by the application. These messages can provide high-level logical information connected to specific use cases. Typical examples are:

The stacktrace of an exception that occurred in a use case.
Warning messages about slow response times from an external system.
Information that a use case has been triggered or terminated.

The application record is probably the most important type of record that is mentioned in this article because you have full control over it. This means that you are responsible for writing the messages.

Each log message must provide useful information that helps you understand the behavior of your application. If you want to know more about application logs, take a look at Eric’s article, which describes an optimal set of best practices for registering applications.

Web server logs and applications

The next interesting and important type is the Log of your web server or applications.

Most business applications are implemented on a Web server, for example, Apache Tomcat or an application server, for example, Wildfly or WebSphere Liberty. Your log files provide information about technical problems and the current status of the server.

The configuration and resources of each server are different, and I will not explain them in detail in this article. But, please be sure to check the documentation of your server and configure it properly. Obtaining the correct information from your server can make the difference between identifying potential problems over time and a server unavailability.

Garbage collector Log

The garbage collector provides automatic memory management. It controls all the objects instantiated in a JVM and eliminates those that are no longer used. This is a very complex task and there are several different garbage collector implementations available.

In general, the garbage collection process in Java is very efficient. It is so efficient that there are many applications that use the default implementation with their default settings. But if your application has to handle high load or use many complex object structures, the performance of the application may decrease over time. This usually happens when the garbage collector needs to spend more and more time to manage the available memory. The garbage collector record provides the necessary information to analyze all the activities of the garbage collector.

The garbage collector log is disabled by default. You must enable it with a set of command line properties.

If you are using JDK 8 or earlier, you can do so using the following properties:

-XX: + PrintGCDetails -Xloggc:

From JDK 9, you must use the following properties:

class = “prettyprint” -Xlog: gc *: file = <path of file-del-gc-log>

After starting your application with these command line properties, your garbage collector will record detailed information about all the operations. Unfortunately, the content and format of the garbage collector log generated depend on the provider and the version of your JVM and the garbage collection algorithm.

System Logs

All the logs discussed above are written by JVM or a running application in JVM. In addition to these records, you must also be familiar with the Log recorded by your operating system.

As a Java developer, I probably never write in these logs. But your operating system logs certain events in these registers. Other applications, which are part of its implementation, can also do so. Therefore, system records are a good place to get an overview of external events.

If you are running your application on Windows, this is the event log. In Linux, you must know the syslog service and its successors.

Windows Log wvent

The Windows event log contains important hardware and software events in the categories, security, configuration, system, and forwarded events applications.

Especially the application events and the system category can be useful to understand the events that have occurred outside of your application. The application category contains events reported by other applications that run on the local Windows system. The events related to the hardware and the controller belong to the system category.

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Linux system Logging

The Linux syslog service and its successors provide a highly configurable registration system. It Log messages triggered by applications or by the operating system in a file or sends them to a remote system.

The Log service used and its configuration depend on your Linux distribution. Please check the documentation to know more about your specific operating system.

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Conclusion

Logging is an important issue with many different facets. In this article, I have summarized 4 important Logs that you should know as a Java developer:

The log of the application is the most obvious. It is written by your application and you are responsible for the content.
If you deploy your application to a Web or application server, you will also need to know the Logs provided by that server.
Garbage collector Logs can provide important information if you need to analyze performance problems.
You can check the system logs to get an overview of all external events that may have affected your application and cause the service incident.

November 17, 2018 0

Benefits and considerations of Java DevOps

DevOps sees the union of practices, philosophies and tools that allow you to create services and applications very quickly. This means that you can improve your applications and evolve at a much faster pace than developers who use traditional software development processes. We talk about DevOps, in general, a lot, but today, let’s dig a little deeper and take a look at Java DevOps specifically.

What is the devOps?

The DevOps is simply a portmanteau of software DEVelopment and IT OPerations. It was called for the first time agile operations and involves different disciplines in the creation, operation and development of applications and services.

Using a devOps model, you are gathering your development team and your operations team, and your work is no longer in silos. These teams, and sometimes in conjunction with the security and quality control teams, work together to implement the new application – development, testing, implementation and, later, operation.

Another important feature – developers often use tools that help automate processes that used to be done manually and, as such, are prone to errors and take much longer to be executed. They also use tools to operate and support applications quickly, as well as to perform tasks without the need for external help, such as implementing code or allocating resources.

What is Java DevOps?

Java DevOps is simply applying DevOps practices and philosophies to the development of Java applications. This means that compartmentalized equipment is no longer necessary when creating Java applications.

Some of the principles you should know include:

Continuous integration. This practice requires developers to periodically mix the code they recorded in a central repository. After the merger, tests and automated constructions are carried out. This allows a team to find problems and quickly eliminate bugs, improve the quality of the application and reduce the time needed to validate their applications. This also helps your team to release new updates more quickly.
Continuous delivery This practice requires that your team release all code changes after writing and then automatically create and test them. If the integration continues to place your code changes in a test environment, continuous delivery will place it in a production environment. What does this mean? You will always have a Java application ready for production!
Microservices. DevOps makes use of microservices. Instead of having a great monolithic Java application, your application is made up of smaller and independent applications.
Infrastructure as a code. This practice means that the infrastructure is assigned and then managed by code and development techniques. Cloud services can help your development teams and operations interact with the infrastructure on a scale that they feel comfortable with. With infrastructure as a code, servers and infrastructure are quickly implemented, automatically corrected and can be easily duplicated. Your team can also automate the administration of the configuration and also take advantage of the policy as a code, in which compliance with regulatory requirements is practically guaranteed.

Benefits of Java DevOps

DevOps take a people’s approach first. In addition to bringing together its development, operations and other equipment, DevOps requires team members to understand the perspective of other team members. This may mean that a developer is sharing their concerns with the team and a SysOp doing the same. This type of understanding can allow team members to help each other, as a developer by creating resources and tools that another team member needs. As such, collaboration is not only motivated by necessity. But, even when you join teams, you also put the focus on responsibility and ownership.
Java DevOps reduces the time to develop a Java application. This will help you deliver the correct Java applications to the end users more quickly and until it becomes more efficient as time passes. You can also adapt more quickly to all the conditions and demands of the constantly changing market.

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Better application quality. DevOps almost always requires a change for continuous integration, which means that each stage of application development is tested and monitored. Each change is also tested. That’s why Java DevOps can guarantee that your Java applications have a positive experience for its users. In addition, the devOps can increase the security rather than hinder it.

4 You do not overload yourself. You can manage and operate your applications, processes and infrastructure at scale.

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Considerations and Risk Mitigation

Here are the things you should consider when switching to the devOps for your Java projects.

Visibility: it would be very tiring and difficult to check if your containers have the correct configuration or do not contain spyware.
Vulnerabilities: If there are problems or if you need to update or remove components, it will be very difficult to follow the different containers.
Consistency: there may be components that are not reviewed. And if you use microservices, this can also mean more configurations that are going to be checked.

The good news is that there are tools you can use to help you manage or minimize these risks. These tools include Artifactory, Sonatype Nexus and RogueWave OpenLogic, as well as several open source and paid tools.

November 16, 2018 0