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Differences Between Oracle JDK and OpenJDK 1. Introduction In this article, we’ll explore the differences between Oracle Java Development Kit and OpenJDK. We’ll first take a quick look at each of them and then make a comparison. After that, we’ll see a list of other JDK implementations. Further reading: Installing… Continue Reading oracle-jdk-vs-openjdk

Compressed OOPs in the JVM 1. Overview The JVM manages memory for us. This removes the memory management burden from the developers, so we don’t need to manipulate object pointers manually, which is proven to be time consuming and error-prone. Under the hood, the JVM incorporates a lot of nifty… Continue Reading jvm-compressed-oops

How to Fix java.lang.UnsupportedClassVersionError 1. Introduction In this short tutorial, we’re going to learn what causes the Java runtime error java.lang.UnsupportedClassVersionError: Unsupported major.minor version and how to fix it. 2. A Look at the Error Let’s start by looking at an example error: Exception in thread “main” java.lang.UnsupportedClassVersionError: com/baeldung/MajorMinorApp has been… Continue Reading java-lang-unsupportedclassversion

The @JvmSynthetic Annotation in Kotlin 1. Introduction Kotlin is a programming language for the JVM and compiles directly to Java Bytecode. However, it’s a lot more concise than Java, and certain JVM features don’t directly fit into the language. Instead, Kotlin provides a set of annotations that we can apply… Continue Reading kotlin-jvm-synthetic

Guide to the Most Important JVM Parameters 1. Overview In this quick tutorial, we’ll explore the most well-known options which can be used to configure the Java Virtual Machine. 2. Explicit Heap Memory – Xms and Xmx Options One of the most common performance-related practices is to initialize the heap… Continue Reading jvm-parameters

JVM Garbage Collectors 1. Overview In this quick tutorial, we will show the basics of different JVM Garbage Collection (GC) implementations. Additionally, we’ll find out how to enable a particular type of Garbage Collection in our applications. 2. Brief Introduction to Garbage Collection From the name, it looks like Garbage… Continue Reading jvm-garbage-collectors

Method Inlining in the JVM 1. Introduction In this tutorial, we’ll take a look at what method inlining is in the Java Virtual Machine and how it works. We’ll also see how to get and read the information related to inlining from the JVM and what we can do with… Continue Reading jvm-method-inlining

Introduction to JVM Code Cache 1. Introduction In this tutorial, we’re going to have a quick look at and learn about the JVM’s code cache memory. 2. What is the Code Cache? Simply put, JVM Code Cache is an area where JVM stores its bytecode compiled into native code. We… Continue Reading jvm-code-cache

How to Warm Up the JVM 1. Overview The JVM is one of the oldest yet powerful virtual machines ever built. In this article, we have a quick look at what it means to warm up a JVM and how to do it. 2. JVM Architecture Basics Whenever a new… Continue Reading java-jvm-warmup