☕️JAVA Language Community

#Video 🎥🖥️

#Java 8 Stream API: Grouping and Aggregating Data with Collectors

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#Book 📚📕
#Kafka Streams in Action, Second Edition.


You can download it in the comment section.
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#Book 📚📕

#Kafka Streams in Action Real-time apps and microservices with the Kafka Streaming API.



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How to Convert a #Stream to List, Set, and Map in #Java? Example Tutorial

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Introduction to PostgreSQL LAG() function:

#PostgreSQL LAG() function provides access to a row that comes before the current row at a specified physical offset. In other words, from the current row the LAG() function can access data of the previous row, or the row before the previous row, and so on.

The LAG() function will be very useful for comparing the values of the current and the previous row.

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https://aws.amazon.com/architecture/this-is-my-architecture/



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Kafka Streams with Spring Cloud Stream
#kafka


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How to limit the SQL query result set to Top-N rows only

#SQL:
SELECT
title
FROM
post
ORDER BY
id DESC
FETCH FIRST 5 ROWS ONLY

#PostgreSQL 8.3 and #MySQL:
SELECT
title
FROM
post
ORDER BY
id DESC
LIMIT 5

#Oracle 11g and older versions:
SELECT *
FROM (
SELECT
title
FROM
post
ORDER BY
id DESC
)
WHERE ROWNUM <= 5


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What is the difference between #LATERAL JOIN and a subquery in PostgreSQL

What is a #LATERAL join?
The LATERAL key word can precede a sub-SELECT FROM item. This allows the sub-SELECT to refer to columns of FROM items that appear before it in the FROM list. (Without LATERAL, each sub-SELECT is evaluated independently and so cannot cross-reference any other FROM item.)

🔗 [ https://stackoverflow.com/questions/28550679/what-is-the-difference-between-lateral-join-and-a-subquery-in-postgresql ]


The following relational database systems support the LATERAL JOIN syntax:
- #Oracle since 12c
- #PostgreSQL since 9.3
- #MySQL since 8.0.14


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Complexities of Data Structure in #Java ☕️



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#Book 📚📕

Get Programming with #Java ☕️
Peggy Fisher (2019)

Get Programming with Java teaches you to write programs in the Java language, starting from the most basic building blocks. In her relatable and personable style, author Peggy Fisher begins by helping you set up a Java programming environment on your computer. Once you’re up and running, you’ll start working with the foundations of Java and object-oriented programming, including classes and objects. Always practical and clear, this carefully-designed tutorial swaps the usual heavy-handed theory for concrete examples and easy-to-follow scenarios.


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#Book 📚📕

Modern Java Recipes: Simple Solutions to Difficult Problems in #Java ☕️ 8 and 9
Kousen, Ken

The introduction of functional programming concepts in Java SE 8 was a drastic change for this venerable object-oriented language. Lambda expressions, method references, and streams fundamentally changed the idioms of the language, and many developers have been trying to catch up ever since. This cookbook will help. With more than 70 detailed recipes, author Ken Kousen shows you how to use the newest features of Java to solve a wide range of problems.


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Design Patterns Implemented in #Java ☕️


🔗 [ https://github.com/mahbodkh/design-pattern ]


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#Java ☕️
#Book 📚📕

Coding and testing are generally considered separate areas of expertise. In this practical book, Java expert Scott Oaks takes the approach that anyone who works with Java should be adept at understanding how code behaves in the Java Virtual Machine—including the tunings likely to help performance. This updated second edition helps you gain in-depth knowledge of Java application performance using both the JVM and the Java platform.


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#Java ☕️
#Book 📚📕


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