“Groovy is what Java would look like if it had been designed in the 21st century. It reduces ceremony, adds power, and keeps everything on the JVM.”

Guillaume Laforge, Groovy Project Lead

Last Updated: March 2026 | Covers: Groovy 5.x, Java 17+ | Total Lessons: 115

Why Learn Groovy?

Groovy is a powerful, optionally typed language for the Java Virtual Machine. It compiles to Java bytecode, integrates seamlessly with any Java library, and cuts your code length in half compared to plain Java. Whether you are writing build scripts with Gradle, automating Jenkins pipelines, building web apps with Grails, or just scripting day-to-day tasks, Groovy makes you more productive.

This Groovy tutorial covers everything from your very first “Hello World” program to advanced topics like metaprogramming, AST transformations, GINQ queries, and the Spock testing framework. Every lesson includes tested code examples with actual output on Groovy 5.x and Java 17+.

How to Use This Tutorial

The 115 lessons below are organized from beginner to advanced. If you are new to Groovy, start with Section 1: Getting Started and work your way through. If you already know the basics, jump to any section that interests you. Every lesson is self-contained with its own examples and output, but they also link to related lessons so you can explore freely.

What you need: Groovy 5.x installed (or use SDKMAN), Java 17+, and any text editor or IDE. Each lesson tells you exactly what to run.

Section 1: Getting Started (4 Lessons)

Install Groovy, set up your IDE, and write your first program. These four lessons get you up and running in minutes.

1. Groovy Hello World – Your First Groovy Program
2. Setting Up Groovy IDE – IntelliJ, VS Code, Eclipse
3. Groovy Def Keyword – Dynamic Typing Explained
4. Groovy -e Command Line Option – Run Scripts Instantly

Section 2: String Operations (12 Lessons)

Strings are the most common data type in any language. This section covers everything from basic manipulation to GString interpolation, multiline strings, and trimming.

5. Groovy String Tutorial – The Complete Guide
6. Groovy String To Integer – All Conversion Methods
7. Groovy Substring – Extract Parts of a String
8. Groovy String take() – Get First N Characters
9. Groovy String reverse() – Reverse Any String
10. Groovy String drop() – Skip First N Characters
11. Groovy Compare Strings – equals, compareTo, and More
12. Groovy String Tokenize – Split Into Tokens
13. Groovy Split String – Complete Guide
14. Groovy GString – String Interpolation Made Easy
15. Groovy Multiline String – Heredoc and Triple Quotes
16. Groovy String Trim – Remove Whitespace

Section 3: Collections and Data Structures (10 Lessons)

Groovy supercharges Java collections with concise syntax and powerful GDK methods. Maps, lists, arrays, sets, and ranges are covered in depth.

17. Groovy Map Tutorial – The Complete Guide
18. Groovy Add To Map – All Methods Explained
19. Groovy List Tutorial – Create, Access, Modify
20. Groovy List To String – Conversion Methods
21. Groovy List Contains, Remove, and Deduplicate
22. Groovy Array Manipulation – Complete Guide
23. Groovy Array Length – Size and Count
24. Groovy Set – Unique Collections
25. Groovy Range – Sequences Made Simple
26. Groovy Collections Overview – Lists, Maps, Sets, and Ranges

Section 4: Control Flow and Loops (6 Lessons)

Groovy offers classic loops plus idiomatic alternatives like each(), times(), and a switch statement that supports ranges, regex, and closures.

27. Groovy For Loop – All Variations
28. Groovy each() – Iterate Like a Pro
29. Groovy times() Loop – Repeat N Times
30. Groovy Switch Statement – Pattern Matching
31. Groovy find() – Locate First Match
32. Groovy findAll() – Filter Collections

Section 5: OOP and Classes (4 Lessons)

Object-oriented programming in Groovy. Covers exception handling, class design, inheritance, interfaces, constructors, and named parameters.

33. Groovy Exception Handling – try-catch-finally
34. Groovy Classes and Inheritance – Complete OOP Guide
35. Groovy Interfaces – Contracts and Polymorphism
36. Groovy Constructors and Named Parameters

Section 6: XML Processing (3 Lessons)

Groovy makes XML parsing and creation effortless with XmlSlurper, XmlParser, and MarkupBuilder.

37. Groovy XmlSlurper – Parse XML the Easy Way
38. Groovy XmlParser vs XmlSlurper – Which to Use
39. Groovy Create and Modify XML Documents

Section 7: File I/O (2 Lessons)

Read, write, copy, and delete files with Groovy’s enhanced File API.

40. Groovy File Operations – Read, Write, Delete
41. Groovy Copy File – Multiple Approaches

Section 8: Output and Timing (2 Lessons)

Groovy’s print, println, printf, and timing utilities for scripts and debugging.

42. Groovy print vs println – Output Methods
43. Groovy Sleep and Timing – Pause Execution

Section 9: Closures and Functional Programming (10 Lessons)

Closures are the heart of idiomatic Groovy. This section covers everything from basics to currying, memoization, trampolining, and Java Stream interop.

44. Groovy Closures – The Complete Guide
45. Groovy Closure Parameters – it, delegate, owner
46. Groovy Higher-Order Functions – collect, inject, groupBy
47. Groovy Curry and Partial Application
48. Groovy Method References and Method Pointers
49. Groovy Closure Composition and Chaining
50. Groovy Functional Interfaces and SAM Types
51. Groovy Streams vs Closures – When to Use What
52. Groovy Memoization – Cache Function Results
53. Groovy Trampoline – Recursive Closures Without Stack Overflow

Section 10: Operators and Expressions (8 Lessons)

Groovy’s operators go far beyond Java. The Elvis operator, safe navigation, spread, spaceship, and more make your code concise and expressive.

54. Groovy Elvis Operator (?:) – Default Values Made Easy
55. Groovy Safe Navigation Operator (?.) – Avoid NullPointerException
56. Groovy Spread Operator (*.) – Apply to All Elements
57. Groovy Spaceship Operator (<=>) – Compare Anything
58. Groovy Regular Expressions – Pattern Matching
59. Groovy Assert and Power Assert – Testing Values
60. Groovy Enum – Constants, Methods, and Best Practices
61. Convert String to Enum in Groovy

Section 11: Metaprogramming and AST (8 Lessons)

Groovy’s metaprogramming lets you add methods at runtime, intercept method calls, and generate code at compile time with AST transformations. This is what makes Groovy uniquely powerful on the JVM.

62. Groovy Metaprogramming – Runtime Magic Explained
63. Groovy MOP (Meta-Object Protocol) – How It Works
64. Groovy ExpandoMetaClass – Add Methods at Runtime
65. Groovy Categories and Mixins – Extend Existing Classes
66. Groovy Traits – Reusable Behavior Composition
67. Groovy AST Transformations – Compile-Time Code Generation
68. Groovy @Immutable – Create Immutable Objects
69. Groovy @Builder – Builder Pattern Made Easy

Section 12: JSON and Data Processing (7 Lessons)

Parse JSON, generate JSON, consume REST APIs, work with CSV files, handle dates, and use GINQ for SQL-like collection queries.

70. Groovy JSON Parsing with JsonSlurper
71. Groovy JSON Output with JsonOutput and JsonBuilder
72. Groovy REST API Consumption – Fetch and Parse JSON
73. Groovy CSV Parsing and Generation
74. Groovy Date and Time – Modern API Guide
75. Groovy GINQ – SQL-Like Collection Queries
76. Groovy Grape – Dependency Management for Scripts

Section 13: SQL and Database (7 Lessons)

Connect to databases, run CRUD operations, manage transactions, use batch processing, and work with the type-safe DataSet API.

77. Groovy SQL – Connect and Query Databases
78. Groovy SQL CRUD – Insert, Update, Delete
79. Groovy SQL Transactions and Connection Pooling
80. Groovy SQL Stored Procedures and Functions
81. Groovy SQL Update and Delete Operations
82. Groovy SQL Transactions and Batch Processing
83. Groovy DataSet – Type-Safe Database Queries

Section 14: Configuration and Tooling (6 Lessons)

Configuration management, logging, the interactive Groovy Shell, custom annotations, Gradle build automation, and property file handling.

84. Groovy ConfigSlurper – Configuration Management
85. Groovy Logging with @Slf4j – Complete Guide
86. Groovy Shell (groovysh) – Interactive REPL
87. Groovy Custom Annotations – Create Your Own
88. Groovy with Gradle – Build Automation Guide
89. Groovy Property Files – Read, Write, and Manage Config

Section 15: Advanced Topics (12 Lessons)

Design patterns, DSLs, concurrency, process execution, generics, testing with Spock, and the latest Groovy 5.0 features.

90. Groovy Grape and @Grab Annotation Guide
91. Groovy Design Patterns – Singleton, Strategy, Observer
92. Groovy DSL and Builder Pattern
93. Groovy Concurrency – Threads, GPars, and Async
94. Groovy Process Execution – Run System Commands
95. Groovy Generics and Type Parameters
96. Groovy Command Chain – Natural Language DSLs
97. Groovy Type Checking – @TypeChecked and @CompileStatic
98. Groovy Operator Overloading – Custom Operators
99. Groovy Testing with Spock Framework
100. Groovy Scripting for Automation – Practical Guide
101. Groovy 5.0 New Features – What Changed and Why It Matters

Section 16: Language Deep Dives (14 Lessons)

Deeper into Groovy’s internals and advanced capabilities: Java interop, date/time APIs, external command execution, static compilation, dependency management, the compilation lifecycle, scripting architecture, GDK internals, design patterns, concurrency, networking, math extensions, additional AST transforms, and the latest Groovy 4/5 features.

102. Groovy-Java Interoperability
103. Groovy Date/Time API
104. Executing External Commands
105. @CompileStatic & @TypeChecked
106. Grape / @Grab Dependency Management
107. Compilation Lifecycle & Architecture
108. Scripting vs Class-Based Execution
109. GDK (Groovy Development Kit) Overview
110. Design Patterns in Groovy
111. Concurrency & GPars
112. HTTP/REST/Networking
113. Number & Math Extensions
114. More AST Transformations
115. Groovy 4/5 Modern Features

Frequently Asked Questions

Ready to start? Jump into Lesson 1: Groovy Hello World and write your first Groovy program in under 5 minutes.

This tutorial is part of the Groovy Cookbook series on TechnoScripts. Once you have completed the Groovy fundamentals, continue with our upcoming Grails 7.x tutorials covering controllers, GORM, GSP views, REST APIs, and more.