Course contents

Java One-Stop Interview Prep

01Java Fundamentals
Module overview
02Core Java & OOP
Module overview
03Collections & Generics
Module overview
04Functional Java (8+)
Module overview
05Multithreading & Concurrency
Module overview
06JVM Internals & Memory
Module overview
1. JVM architecture
  1. How the JVM executes your code
  2. Class loading and classloaders
  3. Bytecode basics
  4. The interpreter and JIT tiers
  5. Interview questions & scenariosInterview
2. Memory areas
  1. Stack vs heap
  2. Metaspace: where classes live
  3. Object layout and headers
  4. Escape analysis
  5. Interview questions & scenariosInterview
3. References
  1. Strong, soft, weak and phantom references
  2. Interview questions & scenariosInterview
4. Garbage collection
  1. How garbage collection works
  2. Generational collection
  3. Serial and Parallel collectors
  4. The G1 collector
  5. ZGC and Shenandoah
  6. Choosing a garbage collector
  7. Interview questions & scenariosInterview
5. Troubleshooting
  1. Reading GC logs
  2. Memory leaks in Java
  3. Types of OutOfMemoryError
  4. Heap dumps and analysis
  5. Thread dumps and analysis
  6. Interview questions & scenariosInterview
6. Module interview question bank
  1. Complete interview question bankBank
07Java Performance Engineering
Module overview
08Java I/O & NIO
Module overview
09Modern Java (17 → 21+)
Module overview
10Design Patterns & SOLID
Module overview
11Real-world Java & Interview Arsenal
Module overview
12Last-Mile Java: What You Can't Skip Before the Interview
Module overview

Module 06

JVM Internals & Memory

What happens inside the JVM: class loading, JIT, memory areas, garbage collectors and troubleshooting memory problems.

Premium3 free lessons5 topics26 lessons & question sets0 ready

By the end of this module you can

Walk through class loading and JIT compilation
Explain how each major garbage collector works
Diagnose leaks and OutOfMemoryErrors from dumps and logs

JVM architecture

How the JVM loads, interprets and compiles your code.

How the JVM executes your codeLessonFreeSoon
Class loading and classloadersLessonPremiumSoon
Bytecode basicsLessonPremiumSoon
The interpreter and JIT tiersLessonPremiumSoon
JVM architecture: interview questions & scenariosInterview Q&APremiumSoon

Memory areas

Stack, heap, Metaspace and how objects are laid out.

Stack vs heapLessonFreeSoon
Metaspace: where classes liveLessonPremiumSoon
Object layout and headersLessonPremiumSoon
Escape analysisLessonPremiumSoon
Memory areas: interview questions & scenariosInterview Q&APremiumSoon

References

Strong, soft, weak and phantom references.

Strong, soft, weak and phantom referencesLessonPremiumSoon
References: interview questions & scenariosInterview Q&APremiumSoon

Garbage collection

How GC works and how each collector differs.

How garbage collection worksLessonFreeSoon
Generational collectionLessonPremiumSoon
Serial and Parallel collectorsLessonPremiumSoon
The G1 collectorLessonPremiumSoon
ZGC and ShenandoahLessonPremiumSoon
Choosing a garbage collectorLessonPremiumSoon
Garbage collection: interview questions & scenariosInterview Q&APremiumSoon

Troubleshooting

GC logs, leaks, OutOfMemoryError and dumps.

Reading GC logsLessonPremiumSoon
Memory leaks in JavaLessonPremiumSoon
Types of OutOfMemoryErrorLessonPremiumSoon
Heap dumps and analysisLessonPremiumSoon
Thread dumps and analysisLessonPremiumSoon
Troubleshooting: interview questions & scenariosInterview Q&APremiumSoon

Finish the module

Module interview question bank

Every interview question worth practising for JVM Internals & Memory, grouped by topic, with model answers, how to say them and what-if follow-ups.

Being written: it grows as the topics in this module are finished

PremiumSoon