Understanding and optimizing the Garbage Collection - Part 3 [pt]

In April, 2012 I published an article (in Portuguese) in Java Magazine #104, about common problems in Java code which ignore how Garbage Collection operates, how to write code to optimize this process and how to analyse the heap memory status in runtime.

Article Understanding and optimizing the Garbage Collection - Part 3 - DevMedia

Summary

The article begins by reviewing JVM options to log the Garbage Collection process activities as well presenting the JConsole tool for a picture of the heap memory situation. Next, states about memory leaks and shows an example of a code with this problem, analysing its runtime execution on JConsole. Lastly, presents other subjects as the finalize() method, weak references and concludes suggesting some good practices.

When is the subject useful

The subject is very relevant to any Java developer, even though the consequences of a badly configured Garbage Collection process won’t be much evident in development environments, certainly will make the difference in production environments. It is important to understand the reasons that cause malfunctioning of the Garbage Collection and how to avoid those scenarios, using good practices for such.

Understanding and optimizing the Garbage Collection - Part 2 [pt]

In March, 2012 I published an article (in Portuguese) in Java Magazine #103, about the operation of the colletors from the JVMs Oracle JRockit (used by WebLogic Java EE application server), IBM Virtual Machine for Java (used by WebSphere Java EE application server), those ones which implement JSR-1 (also known as Real-Time Specification for Java or RTSJ) and Dalvik (used by Android devices).

Article Understanding and optimizing the Garbage Collection - Part 2 - DevMedia

Summary

This article begins by presenting the JVM Oracle JRockit and its heap memory configuration, its collectors and how to use them. Next, presents the JVM IBM Virtual Machine for Java, its heap memory configuration, its collectors and how to use them. From here, presents the JSR-1 specification and its concepts about developing real-time applications in Java, and demonstrates the operation of 5 real-time collectors. Yet, presents the JVM Dalvik and its challenges about Garbage Collection, as well its collector and improvements about memory management.

When is the subject useful

The subject is very relevant to Java developers which work with any of the aforementioned JVMs, to better understand the consequences of using these collectors in particular scenarios. Besides that, Java developers which don’t yet work with any of those JVMs can learn how those options manage to solve in a different way the same challenges the JVM HotSpot faces, adding to your knowledge.

Understanding and optimizing the Garbage Collection - Part 1 [pt]

In February, 2012 I published an article (in Portuguese) in Java Magazine #102, about the Garbage Collection process in Java, detailing how do the JVM HotSpot 6 and 7 collectors work and how to optimize their behavior through JVM options.

Article Understanding and optimizing the Garbage Collection - Part 1 - DevMedia

Summary

This article presents concepts and metrics about Garbage Collection in Java, as well the categorization of the heap memory in generations. Next, presents the JVM HotSpot 6 and its overall operation with Garbage Collection, as much as its customization through JVM options. From here, explains about each collector, how does it operate, its customization options and implementations, making a final comparison illustrating when is it more proper to use each one of the available collectors. Yet, presents JVM HotSpot 7 and its new collector, its overall operation and customization options.

When is the subject useful

The subject is very relevant to any Java developer, even though the consequences of a badly configured Garbage Collection process won’t be much evident in development environments, certainly will make the difference in production environments. It is important to understand the reasons that cause unexpected behavior in the Garbage Collection when operated by multiple processors and big data.