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--- java:java [2022/07/26 06:59] – [c3p0 connection pool] admin
+++ java:java [2024/05/31 05:22] (current) – [Random in Java] admin
@@ Line 401: / Line 401: @@
 // so add 1 to make it inclusive
 ThreadLocalRandom.current().nextInt(min, max + 1);
+</code>
+==== Md5 ====
+<code java>
+import java.util.HashMap;
+import java.security.MessageDigest;
+public static String md5(String original) {
+    try{
+        MessageDigest md = MessageDigest.getInstance("MD5");
+        md.update(original.getBytes());
+        byte[] digest = md.digest();
+        StringBuffer sb = new StringBuffer();
+        for (byte b : digest) {
+            sb.append(String.format("%02x", b & 0xff));
+        }
+        return sb.toString();
+    }catch(Exception e){
+        return "";
+    }
+}
 </code>
 ==== Java Reflection ====
@@ Line 562: / Line 581: @@
   * **Atomic variables** have features that minimize synchronization and help avoid memory consistency errors.
   * **ThreadLocalRandom** (in JDK 7) provides **efficient generation of pseudorandom numbers from multiple threads**.
-=== Executor Interfaces ===
-=== Thread pools ===
+==== Thread pools ====
+{{:java:thread-pool-tasks.png|}}
 refer:
-  * https://docs.oracle.com/javase/tutorial/essential/concurrency/pools.html
+  * https://www.baeldung.com/thread-pool-java-and-guava
-  * http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/ThreadPoolExecutor.html
   * http://howtodoinjava.com/2012/10/20/how-to-use-blockingqueue-and-threadpoolexecutor-in-java
+  * http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/ThreadPoolExecutor.html
 Thread pools address two different problems:
   * They usually provide improved performance when **executing large numbers of asynchronous tasks**, due to reduced per-task invocation overhead
@@ Line 1252: / Line 1272: @@
   * {{:java:pooling.jpg|}}
-==== Hibernate connection pooling and mysql connection timeout ====
+==== Default Hibernate connection pooling ====
-Below are basic steps config for connections in Hibernate(each connection in MySQL was a session in Hibernate):
+Below are basic steps config for connections in Hibernate(each connection in MySQL was a session in Hibernate)(refer: https://docs.jboss.org/hibernate/stable/core.old/reference/en/html/configuration-hibernatejdbc.html):
   - Config max connections in MySQL:
     * config temporary in MySQL Admin console:<code sql>