Java ConcurrentHashMap
ConcurrentHashMap is designed to support concurrent access from multiple threads without the need for external synchronization. It achieves this by using var...
Recent Posts
Certbot on Oracle Cloud VM
Try to get a certificate from Let’s encrypt on Oracle’s compute instance (vm) with command certbot certonly --standalone but keeps getting error: Certbot fai...
AWK 101
Note for Learning Awk Is Essential For Linux Users download awk is a tool to process text, line by line. Variable $0 means whole line, $1 means the fi...
Java Features By Version
Java 8 https://www.oracle.com/java/technologies/javase/8-whats-new.html Functional Interfaces and Lambda Expressions Default and static metho...
PlantUML in VS Code
Test #@startuml class ExampleClass { -mPrivate: String +mPublic : int #mProtected: boolean ~mDefault: float mNothing: long +void pu...
Lesson Learned - Java Timer
Issue When you use Java Timer (java.util.Timer) to set a task for future execution, you should be really careful. Java Timer use currentTimeMillis, which wi...
Java SE: Programming Complete - 9
https://learn.oracle.com/ols/course/java-se-programming-complete/82508/85200 Collections ####
Java SE: Programming Complete - 8
https://learn.oracle.com/ols/course/java-se-programming-complete/82508/85200 Arrays and Loops Arrays An array is a fixed-length collection of eleme...
Java SE: Programming Complete - 7
https://learn.oracle.com/ols/course/java-se-programming-complete/82508/85200 Interface Java Interface An interface defines a set of features that c...
Java SE: Programming Complete - 6
https://learn.oracle.com/ols/course/java-se-programming-complete/82508/85200 Inheritance Extend Classes java.lang.Object is an ultimate paraent of ...