Java Collections Series
Last updated: January 18, 2024
Mocking is an essential part of unit testing, and the Mockito library makes it easy to write clean and intuitive unit tests for your Java code.
Get started with mocking and improve your application tests using our Mockito guide:
Handling concurrency in an application can be a tricky process with many potential pitfalls. A solid grasp of the fundamentals will go a long way to help minimize these issues.
Get started with understanding multi-threaded applications with our Java Concurrency guide:
Spring 5 added support for reactive programming with the Spring WebFlux module, which has been improved upon ever since. Get started with the Reactor project basics and reactive programming in Spring Boot:
Since its introduction in Java 8, the Stream API has become a staple of Java development. The basic operations like iterating, filtering, mapping sequences of elements are deceptively simple to use.
But these can also be overused and fall into some common pitfalls.
To get a better understanding on how Streams work and how to combine them with other language features, check out our guide to Java Streams:
Explore Spring Boot 3 and Spring 6 in-depth through building a full REST API with the framework:
Yes, Spring Security can be complex, from the more advanced functionality within the Core to the deep OAuth support in the framework.
I built the security material as two full courses - Core and OAuth, to get practical with these more complex scenarios. We explore when and how to use each feature and code through it on the backing project.
You can explore the course here:
Spring Data JPA is a great way to handle the complexity of JPA with the powerful simplicity of Spring Boot.
Get started with Spring Data JPA through the guided reference course:
Refactor Java code safely — and automatically — with OpenRewrite.
Refactoring big codebases by hand is slow, risky, and easy to put off. That’s where OpenRewrite comes in. The open-source framework for large-scale, automated code transformations helps teams modernize safely and consistently.
Each month, the creators and maintainers of OpenRewrite at Moderne run live, hands-on training sessions — one for newcomers and one for experienced users. You’ll see how recipes work, how to apply them across projects, and how to modernize code with confidence.
Join the next session, bring your questions, and learn how to automate the kind of work that usually eats your sprint time.
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List
- A Guide to the Java LinkedList
- Guide to the Java ArrayList
- Immutable ArrayList in Java
- Guide to CopyOnWriteArrayList
- Multi Dimensional ArrayList in Java
- Converting Iterator to List
- Java – Get Random Item/Element From a List
- Partition a List in Java
- Removing All Nulls From a List in Java
- Removing All Duplicates From a List in Java
- Check if Two Lists Are Equal in Java
- How to Find an Element in a List with Java
- Java List UnsupportedOperationException
- Copy a List to Another List in Java
- Remove All Occurrences of a Specific Value from a List
- Add Multiple Items to an Java ArrayList
- Remove the First Element from a List
- Ways to Iterate Over a List in Java
- Intersection of Two Lists in Java
- How to Count Duplicate Elements in Arraylist
- Finding the Differences Between Two Lists in Java
- Reversing a Linked List in Java
- Assert Two Lists for Equality Ignoring Order in Java
- Java List Initialization in One Line
- Determine the Class of a Generic Type in Java
- Converting a Java List to a Json Array
- Finding All Duplicates in a List in Java
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Sets
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Maps
- A Guide to Java HashMap
- The Java HashMap Under the Hood
- A Guide to TreeMap in Java
- Java TreeMap vs HashMap
- Guide to WeakHashMap in Java
- A Guide to ConcurrentMap
- Guide to the ConcurrentSkipListMap
- An Introduction to Java.util.Hashtable Class
- A Guide to LinkedHashMap in Java
- A Guide to EnumMap
- Immutable Map Implementations in Java
- Java Map With Case-Insensitive Keys
- Java HashMap Load Factor
- Collections.synchronizedMap vs. ConcurrentHashMap
- How to Store Duplicate Keys in a Map in Java?
- Initialize a HashMap in Java
- Merging Two Maps with Java
- Sort a HashMap in Java
- Comparing Two HashMaps in Java
- Using the Map.Entry Java Class
- Working With Maps Using Streams
- Iterate Over a Map in Java
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Queues
- Guide to PriorityBlockingQueue in Java
- Guide to java.util.concurrent.BlockingQueue
- A Guide to Java SynchronousQueue
- Guide to the Java TransferQueue
- Guide to DelayQueue
- Introduction to the Java ArrayDeque
- Guide to the Java Queue Interface
- A Guide to Concurrent Queues in Java
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Convert Collections
- Converting Between an Array and a List in Java
- Converting Between an Array and a Set in Java
- Converting Between a List and a Set in Java
- Convert a Map to an Array, List or Set in Java
- How to Convert List to Map in Java
- Map to String Conversion in Java
- Arrays.asList vs new ArrayList(Arrays.asList())
- Collecting Stream Elements into a List in Java
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Operations on Collection
- The Difference Between Collection.stream().forEach() and Collection.forEach()
- Sorting in Java
- Shuffling Collections in Java
- Flattening Nested Collections in Java
- Zipping Collections in Java
- Join and Split Arrays and Collections in Java
- Java – Combine Multiple Collections
- Finding Max/Min of a List or Collection
- Collect a Java Stream to an Immutable Collection
- Java Convenience Factory Methods for Collections
- Java Collections Interview Questions
- A Guide to Iterator in Java
- Getting the Size of an Iterable in Java
- Removing Elements from Java Collections
- Time Complexity of Java Collections
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Apache Commons Collections
- Apache Commons Collections Bag
- Apache Commons Collections SetUtils
- Apache Commons Collections OrderedMap
- Apache Commons Collections BidiMap
- A Guide to Apache Commons Collections CollectionUtils
- Apache Commons Collections MapUtils
- Guide to Apache Commons CircularFifoQueue
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Guava Collections
- Guava Collections Cookbook
- Guide to Guava Multimap
- Guava – Join and Split Collections
- Guide to Guava Table
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Other Collections
- Introduction to Eclipse Collections
- Introduction to PCollections
- Filtering and Transforming Collections in Guava
- Hamcrest Collections Cookbook
- Implementing a Binary Tree in Java
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