Effectively reading and understanding existing code is a developer’s superpower. In this book, you’ll master techniques for code profiling, advanced debugging, and log evaluation to find and fix bugs and performance problems.

In Troubleshooting Java: Read, debug, and optimize JVM applications you will learn how to:

Determine what code does the first time you see it
Expose code logic problems
Evaluate heap dumps to find memory leaks
Monitor CPU consumption to optimize execution
Use thread dumps to find and solve deadlocks
Easily follow a service-oriented or microservices system
Properly use logging to better understand Java app execution
Use Java debuggers efficiently

Searching for bugs, detangling messy legacy code, or evaluating your codebase for new features sucks up much of a developer's time. Troubleshooting Java: Read, debug, and optimize JVM applications teaches code investigation techniques that will help you efficiently understand how Java apps work, how to optimize them, and how to fix the bugs that break them. You’ll go from the basics of debugging to advanced methods for locating problems in microservices architectures, and save yourself hours—or even days—of time. Each new technique is explained with lively illustrations and engaging real-world examples.

About the technology
Fact: Over the course of your career, you’ll spend far more time reading code than you will writing it. The code investigation skills in this book will radically improve your efficiency in understanding and improving Java applications.

About the book
Troubleshooting Java: Read, debug, and optimize JVM applications presents practical techniques for exploring and repairing unfamiliar code. In it, you’ll learn timesaving practices for discovering hidden dependencies, discovering the root causes of crashes, and interpreting unexpected results. Go beyond profiling and debugging and start understanding how Java applications really work.

What's inside

Determine what code does the first time you see it
Evaluate heap dumps to find memory leaks
Monitor CPU consumption to optimize execution
Use thread dumps to find and solve deadlocks
Uncover glitches in code logic
Locate intermittent runtime problems

About the reader
For intermediate Java developers.

About the author
Laurentiu Spilca is a skilled Java and Spring developer and an experienced technology instructor. He is the author of Spring Start Here and Spring Security in Action.

Table of Contents
PART 1 - THE BASICS OF INVESTIGATING A CODEBASE
1 Revealing an app’s obscurities
2 Understanding your app’s logic through debugging techniques
3 Finding problem root causes using advanced debugging techniques
4 Debugging apps remotely
5 Making the most of logs: Auditing an app’s behavior
PART 2 - DEEP ANALYSIS OF AN APP’S EXECUTION
6 Identifying resource consumption problems using profiling techniques
7 Finding hidden issues using profiling techniques
8 Using advanced visualization tools for profiled data
9 Investigating locks in multithreaded architectures
10 Investigating deadlocks with thread dumps
11 Finding memory-related issues in an app’s execution
PART 3 - FINDING PROBLEMS IN LARGE SYSTEMS
12 Investigating apps’ behaviors in large systems