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Tag Archives: Performance

Performance tests for slow networks with tc

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tl;dr: you can easily replicate slow network conditions which makes it easier to performance test them. Smartphones have made both mobile websites and apps that have to connect in mobile situations a lot more common. There’s also a lot of value to be had in servicing these kind of customers and in recent years we’ve arrived at the stage where ...

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ArrayList Using Memory Mapped File

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Introduction In-Memory computing is picking up due to affordable hardware, most of the data is kept in RAM to meet latency and throughput goal, but keeping data in RAM create Garbage Collector overhead especially if you don’t pre allocate. So effectively we need garbage less/free approach to avoid GC hiccups Garbage free/less data structure There are couple of option to achieve ...

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C++ like Java for low latency

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Overview Previously I wrote an article on C like Java.  This is term I had come across before. However, on reflection I thought C++ like Java is a better term as you still use OOP practices, (which not C-like) but you put more work into managing and recycling memory yourself. The term I favour now is “low level” Java programming. ...

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Reducing memory consumption by 20x

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This is going to be another story sharing our recent experience with memory-related problems. The case is extracted from a recent customer support case, where we faced a badly behaving application repeadedly dying with OutOfMemoryError messages in production. After running the application with Plumbr attached we were sure we were not facing a memory leak this time. But something was ...

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JVM Performance Magic Tricks

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HotSpot, the JVM we all know and love, is the brain in which our Java and Scala juices flow. Over the years, it’s been improved and tweaked by more than a handful of engineers, and with every iteration, the speed and efficiency of its code execution is nearing that of native compiled code. At its core lies the JIT (“Just-In-Time”) ...

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Improve Performance by caching and compression

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Web page designs are becoming innovative with rich interface which involve extra code such as java scripts, css, and images etc. Most of the end-user response time tied-up in downloading these components.Optimizations of number of http requests and response size are the key parameters to improve the web application performance. This article explains about caching filter and compression filter that ...

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HotSpot GC Thread CPU footprint on Linux

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The following question will test your knowledge on garbage collection and high CPU troubleshooting for Java applications running on Linux OS. This troubleshooting technique is especially crucial when investigating excessive GC and / or CPU utilization. It will assume that you do not have access to advanced monitoring tools such as Compuware dynaTrace or even JVisualVM. Future tutorials using such ...

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Arrays.sort versus Arrays.parallelSort

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We all have used Arrays.sort to sort objects and primitive arrays. This API used merge sort OR Tim Sort underneath to sort the contents as shown below:                   public static void sort(Object[] a) { if (LegacyMergeSort.userRequested) legacyMergeSort(a); else ComparableTimSort.sort(a); } This is all done sequentially, even though merge sort uses divide and ...

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Java StringBuilder myth debunked

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The myth Concatenating two Strings with the plus operator is the source of all evil — Anonymous Java dev NOTE: The source code for the tests discussed here can be found on Github It’s from university time that I learned to regard String concatenation in Java using the ‘+’ plus operator as a deadly performance sin. Recently there has been ...

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OpenJPA: Memory Leak Case Study

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This article will provide the complete root cause analysis details and resolution of a Java heap memory leak (Apache OpenJPA leak) affecting an Oracle Weblogic server 10.0 production environment. This post will also demonstrate the importance to follow the Java Persistence API best practices when managing the javax.persistence.EntityManagerFactory lifecycle.             Environment specifications Java EE server: ...

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