🚀 A complete developer-friendly guide and hands-on toolkit to analyze, troubleshoot, and optimize Java memory usage using heap dumps and modern profilers like JProfiler, jmap, and Eclipse MAT.

• 🔍 Introduction
• 🛠️ Tools You’ll Need
• 📤 Generating a Heap Dump
• 🧪 Sample Java Code to Generate Heap Dump
• 📥 Analyzing Heap Dump with JProfiler
  • 🔢 Step-by-Step
  • 🧭 Key Views to Explore
• 🔎 Understanding Key Concepts
• 📊 Jargon Explained with Examples
• 🧠 Retained Size vs Shallow Size
• 🚨 Identifying Memory Leaks
• 🌐 References & Official Docs
• 🏷️ Tags & Topics
• 🙌 Contributing
• 📢 Spread the Word
• 💻 Author

This repository is your go-to guide for understanding Java heap dumps, analyzing them using JProfiler, and diagnosing memory leaks or performance bottlenecks. Whether you're debugging a production crash or fine-tuning memory usage—this toolkit has you covered.

jmap -dump:format=b,file=heapdump.hprof <PID>

• <PID> is the Java process ID.
• heapdump.hprof is the name of the output file.

import com.sun.management.HotSpotDiagnosticMXBean;
import java.lang.management.ManagementFactory;

public class HeapDumpExample {
    public static void main(String[] args) throws Exception {
        HotSpotDiagnosticMXBean mxBean = ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class);
        mxBean.dumpHeap("heapdump.hprof", true);
        System.out.println("Heap dump created!");
    }
}

1. Open JProfiler

2. Go to File → Open Snapshot

3. Select your .hprof file

4. Start analyzing with:

   • Heap Walker
   • Reference Graph
   • Dominator Tree
   • GC Roots
   • Allocation Call Tree

Object A retains B and C
├── B
└── C

If B and C are only accessible through A,
then A's retained size = shallow size of A + B + C

• Shallow Size: Just A
• Retained Size: A + all exclusively retained objects

• High retained sizes
• Excessive number of instances of a class
• Objects held by static fields, thread locals, or long reference chains
• Large collections (Map, List) with old or unnecessary data

Use JProfiler features like:

• Leak Suspect Reports
• Dominator Tree
• Reference Graph

• Oracle JDK jmap
• Eclipse MAT Documentation
• JProfiler Overview
• Java Memory Leaks - Baeldung
• YouTube: Heap Dump Tutorials

#Java #HeapDump #JProfiler #MemoryLeak #GC #MAT #MemoryOptimization #JVM #ReferenceGraph #PerformanceTuning

Pull requests welcome! Feel free to add:

• Additional tools
• More case studies
• Tips for JVM tuning
• Alternative profiling tools (YourKit, VisualVM)

If this helped you:

• ⭐ Star the repo
• 🔁 Share with your team
• 📦 Fork and enhance

Crafted with 💙 by @Sharique55