AnhDH.

Snippets

Small, reusable code snippets pulled straight from the articles.

Step 1: Establishing a Connection

From the post “What Happens When MySQL Executes a SELECT Query?”

js
mysql> show processlist;
+----+------+-----------+------+---------+------+-------+------+
| Id | User | Host      | db   | Command | Time | State | Info |
|  6 | root | localhost | NULL | Sleep   | 736  |       | NULL |
|  7 | root | localhost | NULL | Query   | 0    | init  | 0    |
+----+------+-----------+------+---------+------+-------+------+
2 rows in set (0.00 sec)

Step 2: Parsing the SQL Syntax

From the post “What Happens When MySQL Executes a SELECT Query?”

js
mysql> select * form Member;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'form Member' at line 1

Preprocessing Stage (Preprocessor)

From the post “What Happens When MySQL Executes a SELECT Query?”

js
mysql> select * from test;
ERROR 1146 (42S02): Table 'mysql.test' doesn't exist

What are the characteristics of variables, methods, and classes marked with the final keyword?

From the post “Top 10 Java Core Interview Questions”

js
final int x = 10;
// x cannot be reassigned

What's the difference between override and overload?

From the post “Top 10 Java Core Interview Questions”

js
public class Example {
    public void printInfo(String message) {
        System.out.println("Message: " + message);
    }

    public void printInfo(int number) {
        System.out.println("Number: " + number);
    }
}

Implementing a Distributed Lock with Redis

From the post “Distributed Locks and How to Implement Them with Redis”

js
func update() {
   try {
       // Try lock "key" with TTL = X seconds in Y seconds
       if(tryLock(key, value, X, Y)) {
           // Handle get, calculate and update resource
           // Return
       }
   } finally {
       unLock(key, value)
   }
   //
   throw Exception("Try lock timeout")
}