Java class loading – performance impact!

java.lang.ClassLoader#loadClass() API is used by 3rd party libraries, JDBC Drivers, frameworks, application servers to load a java class into the memory. Application developers don’t use this API frequently. However when they use the APIs such as ‘java.lang.Class.forName()’ or ‘org.springframework.util.ClassUtils.forName()’, they internally call this 'java.lang.ClassLoader#loadClass()' API. Frequent usage of this API amongst different threads at runtime... Continue Reading →

Benefits of setting initial and maximum memory size to the same value

When we launch applications, we specify the initial memory size and maximum memory size. For the applications that run on JVM (Java Virtual Machine), initial and maximum memory size is specified through ‘-Xms’ and ‘-Xmx’ arguments. If Java applications are running on containers, it's specified through ‘-XX: InitialRAMPercentage’ and ‘-XX: MaxRAMPercentage’ arguments. Most enterprises set... Continue Reading →

Memory leak due to improper exception handling

In this post let's discuss an interesting memory problem we confronted in the production environment and how we went about solving it. This application would take traffic for a few hours after that it would become unresponsive. It wasn't clear what was causing the unresponsiveness in the application. Technology stack This application was running on... Continue Reading →

Java UUID generation – Performance impact

Java developers tend to use 'java.util.UUID#randomUUID()' API, to generate a UUID (Universally Unique Identifier) number (i.e., 'b8bbcbed-ca07-490c-8711-5118ee0af2f9'). Under certain circumstances, using this API can affect your application’s availability. Let’s discuss this API in this post with a real-world example. How does  'java.util.UUID#randomUUID()' API works? java.util.UUID#randomUUID() API internally uses 'entropy' in the operating system to generate... Continue Reading →

I/O waiting CPU time – ‘wa’ in top

CPU consumption in Unix/Linux operating systems are studied using 8 different metrics: User CPU time, System CPU time, nice CPU time, Idle CPU time, Waiting CPU time, Hardware Interrupt CPU time, Software Interrupt CPU time, Stolen CPU time. In this article let us study about ‘waiting CPU time’. What is ‘waiting’ CPU time? Waiting CPU... Continue Reading →

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