OutOfMemoryError in Java occurs when the JVM cannot allocate memory due to insufficient space in the heap, even after garbage collection. Different types and causes exist, each requiring specific fixes. A one-page document summarizing this information is available, which the author finds visually appealing for display.
The 'Kill Process or sacrifice child' OutOfMemoryError occurs when processes exceed available RAM, prompting the Operating System to terminate certain processes to safeguard others. This often happens in containerized environments. Solutions include increasing RAM, minimizing unnecessary processes, and optimizing memory usage with tools like yCrash.
The content discusses troubleshooting OutOfMemoryError using the Eclipse MAT tool. It highlights best practices and tips for effectively debugging memory issues. A video tutorial is available for a more in-depth understanding.
The article describes a production issue where an AWS EC2 application instance became unresponsive while others continued functioning. Investigation revealed repeated "TCP: out of memory" messages from the dmesg command. After an unsuccessful server restart, the instance was rebooted, resolving the issue. Kernel properties were identified to optimize TCP memory limits.
This article discusses useful JVM arguments for handling OutOfMemoryError, which assist in memory troubleshooting. It covers -XX:+HeapDumpOnOutOfMemoryError for capturing heap dumps, -XX:OnOutOfMemoryError for executing scripts, -XX:+CrashOnOutOfMemoryError and -XX:+ExitOnOutOfMemoryError for abrupt application exits, highlighting the importance of graceful handling in both cases.
Eclipse Memory Analyzer (MAT) is a tool for heap dump analysis, featuring 'incoming references' and 'outgoing references'. Incoming references are objects that reference a particular object, while outgoing references are objects that are referenced by it. The article illustrates these concepts with a sample application, clarifying their differences.
Eclipse MAT (Memory Analyzer Tool) is utilized for analyzing heap dumps to address memory issues, distinguishing between Shallow Heap and Retained Heap sizes. Shallow Heap refers to an object's size, whereas Retained Heap indicates memory freed if the object is garbage collected. Examples illustrate these concepts using an object model, revealing how references affect retained heap calculations.
Java.lang.VirtualMachineError is an exception thrown by the JVM due to internal errors or resource limitations. It includes four types: OutOfMemoryError, StackOverflowError, InternalError, and UnknownError, each with distinct causes. Understanding these errors is vital for diagnosing and resolving potential issues in Java applications, particularly for DevOps professionals.
Procedures to diagnose and solve all the 5 types of OutOfMemoryErrors that happen within the JVM heap are same. In this article, let's explore how to diagnose these 5 types of OutOfMemoryErrors.