From 2a2707c4e79936e264b1f863e5d0056e05131c6f Mon Sep 17 00:00:00 2001
From: Jason Lu <wjlukuan@hotmail.com>
Date: Wed, 19 Feb 2025 13:21:49 +0800
Subject: [PATCH] add maven as package manager add ShowObjectHeader.java to
 show object header

---
 .idea/compiler.xml                            | 14 +++++++
 .idea/inspectionProfiles/Project_Default.xml  |  8 ++++
 .idea/jarRepositories.xml                     | 20 +++++++++
 .idea/misc.xml                                |  8 ++++
 java_test.iml                                 |  7 +---
 pom.xml                                       | 38 +++++++++++++++++
 src/{ => main/java}/jvm/ObjectCreate.java     |  4 +-
 src/main/java/jvm/ShowObjectHeader.java       | 42 +++++++++++++++++++
 .../createthread/CreateByAnonymousClass.java  |  2 +-
 .../jvm}/createthread/CreateByCallable.java   |  2 +-
 .../CreateByCompletableFuture.java            |  2 +-
 .../createthread/CreateByExecutorService.java |  2 +-
 .../jvm}/createthread/CreateByForkJoin.java   |  2 +-
 .../jvm}/createthread/CreateByFutureTask.java |  2 +-
 .../jvm}/createthread/CreateByRunnable.java   |  2 +-
 .../jvm}/createthread/CreateByThread.java     |  2 +-
 .../createthread/CreateByThreadGroup.java     |  2 +-
 .../java/jvm}/createthread/CreateByTimer.java |  2 +-
 src/{ => main/java}/recursive/TreeNode.java   |  2 +-
 .../java}/recursive/TreeStructure.java        |  2 +-
 20 files changed, 146 insertions(+), 19 deletions(-)
 create mode 100644 .idea/compiler.xml
 create mode 100644 .idea/inspectionProfiles/Project_Default.xml
 create mode 100644 .idea/jarRepositories.xml
 create mode 100644 pom.xml
 rename src/{ => main/java}/jvm/ObjectCreate.java (79%)
 create mode 100644 src/main/java/jvm/ShowObjectHeader.java
 rename src/{ => main/java/jvm}/createthread/CreateByAnonymousClass.java (91%)
 rename src/{ => main/java/jvm}/createthread/CreateByCallable.java (94%)
 rename src/{ => main/java/jvm}/createthread/CreateByCompletableFuture.java (96%)
 rename src/{ => main/java/jvm}/createthread/CreateByExecutorService.java (94%)
 rename src/{ => main/java/jvm}/createthread/CreateByForkJoin.java (92%)
 rename src/{ => main/java/jvm}/createthread/CreateByFutureTask.java (91%)
 rename src/{ => main/java/jvm}/createthread/CreateByRunnable.java (90%)
 rename src/{ => main/java/jvm}/createthread/CreateByThread.java (89%)
 rename src/{ => main/java/jvm}/createthread/CreateByThreadGroup.java (93%)
 rename src/{ => main/java/jvm}/createthread/CreateByTimer.java (91%)
 rename src/{ => main/java}/recursive/TreeNode.java (96%)
 rename src/{ => main/java}/recursive/TreeStructure.java (97%)

diff --git a/.idea/compiler.xml b/.idea/compiler.xml
new file mode 100644
index 0000000..4fc82c1
--- /dev/null
+++ b/.idea/compiler.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <annotationProcessing>
+      <profile name="Maven default annotation processors profile" enabled="true">
+        <sourceOutputDir name="target/generated-sources/annotations" />
+        <sourceTestOutputDir name="target/generated-test-sources/test-annotations" />
+        <outputRelativeToContentRoot value="true" />
+        <module name="java_test" />
+      </profile>
+    </annotationProcessing>
+    <bytecodeTargetLevel target="21" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/inspectionProfiles/Project_Default.xml b/.idea/inspectionProfiles/Project_Default.xml
new file mode 100644
index 0000000..db0f74e
--- /dev/null
+++ b/.idea/inspectionProfiles/Project_Default.xml
@@ -0,0 +1,8 @@
+<component name="InspectionProjectProfileManager">
+  <profile version="1.0">
+    <option name="myName" value="Project Default" />
+    <inspection_tool class="AutoCloseableResource" enabled="true" level="WARNING" enabled_by_default="true">
+      <option name="METHOD_MATCHER_CONFIG" value="java.util.Formatter,format,java.io.Writer,append,com.google.common.base.Preconditions,checkNotNull,org.hibernate.Session,close,java.io.PrintWriter,printf,java.io.PrintStream,printf,java.lang.foreign.Arena,ofAuto,java.lang.foreign.Arena,global,java.util.concurrent.Executors,newFixedThreadPool" />
+    </inspection_tool>
+  </profile>
+</component>
\ No newline at end of file
diff --git a/.idea/jarRepositories.xml b/.idea/jarRepositories.xml
new file mode 100644
index 0000000..b074d70
--- /dev/null
+++ b/.idea/jarRepositories.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RemoteRepositoriesConfiguration">
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Maven Central repository" />
+      <option name="url" value="https://repo1.maven.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="jboss.community" />
+      <option name="name" value="JBoss Community repository" />
+      <option name="url" value="https://repository.jboss.org/nexus/content/repositories/public/" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Central Repository" />
+      <option name="url" value="https://maven.aliyun.com/repository/central" />
+    </remote-repository>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
index 6f29fee..fdc35ea 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -1,5 +1,13 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="MavenProjectsManager">
+    <option name="originalFiles">
+      <list>
+        <option value="$PROJECT_DIR$/pom.xml" />
+      </list>
+    </option>
+  </component>
   <component name="ProjectRootManager" version="2" languageLevel="JDK_21" default="true" project-jdk-name="21" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
diff --git a/java_test.iml b/java_test.iml
index c90834f..a80f8af 100644
--- a/java_test.iml
+++ b/java_test.iml
@@ -1,11 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <module type="JAVA_MODULE" version="4">
-  <component name="NewModuleRootManager" inherit-compiler-output="true">
-    <exclude-output />
-    <content url="file://$MODULE_DIR$">
+  <component name="AdditionalModuleElements">
+    <content url="file://$MODULE_DIR$" dumb="true">
       <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
     </content>
-    <orderEntry type="inheritedJdk" />
-    <orderEntry type="sourceFolder" forTests="false" />
   </component>
 </module>
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
new file mode 100644
index 0000000..23124b4
--- /dev/null
+++ b/pom.xml
@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.kuaslab</groupId>
+    <artifactId>java-learning</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>21</maven.compiler.source>
+        <maven.compiler.target>21</maven.compiler.target>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.openjdk.jol</groupId>
+            <artifactId>jol-core</artifactId>
+            <version>0.17</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.8.1</version>
+                <configuration>
+                    <source>{maven.compiler.source}</source>
+                    <target>{maven.compiler.target}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>
\ No newline at end of file
diff --git a/src/jvm/ObjectCreate.java b/src/main/java/jvm/ObjectCreate.java
similarity index 79%
rename from src/jvm/ObjectCreate.java
rename to src/main/java/jvm/ObjectCreate.java
index 1431aad..3af3da1 100644
--- a/src/jvm/ObjectCreate.java
+++ b/src/main/java/jvm/ObjectCreate.java
@@ -1,7 +1,7 @@
-package jvm;
+package main.java.jvm;
 
 /**
- * This class is intended to demo how jvm create object and invoke constructor. Please see byte code.
+ * This class is intended to demo how main.java.jvm create object and invoke constructor. Please see byte code.
  * use javap -v ObjectCreate.class  or javap -c  ObjectCreate.class to see byte code
  */
 public class ObjectCreate {
diff --git a/src/main/java/jvm/ShowObjectHeader.java b/src/main/java/jvm/ShowObjectHeader.java
new file mode 100644
index 0000000..ec89b7d
--- /dev/null
+++ b/src/main/java/jvm/ShowObjectHeader.java
@@ -0,0 +1,42 @@
+package jvm;
+
+import org.openjdk.jol.info.ClassLayout;
+
+public class ShowObjectHeader {
+
+    static final Object lock = new Object();
+
+    public void syncObject() {
+        synchronized (lock) {
+            try {
+                Thread.sleep(1000);
+                System.out.println("enter sync");
+                System.out.println(ClassLayout.parseInstance(lock).toPrintable());
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+    public static void main(String[] args) throws InterruptedException {
+        ShowObjectHeader showObjectHeader = new ShowObjectHeader();
+        System.out.println("newly created");
+        System.out.println(ClassLayout.parseInstance(lock).toPrintable());
+
+        Thread t1 = new Thread(showObjectHeader::syncObject);
+        t1.start();
+        t1.join();
+
+        Thread t2 = new Thread(showObjectHeader::syncObject);
+        Thread t3 = new Thread(showObjectHeader::syncObject);
+
+        t2.start();
+        t3.start();
+
+        t2.join();
+        t3.join();
+        System.out.println("after sync");
+        System.out.println(ClassLayout.parseInstance(lock).toPrintable());
+
+    }
+}
diff --git a/src/createthread/CreateByAnonymousClass.java b/src/main/java/jvm/createthread/CreateByAnonymousClass.java
similarity index 91%
rename from src/createthread/CreateByAnonymousClass.java
rename to src/main/java/jvm/createthread/CreateByAnonymousClass.java
index 6643a7d..13188b0 100644
--- a/src/createthread/CreateByAnonymousClass.java
+++ b/src/main/java/jvm/createthread/CreateByAnonymousClass.java
@@ -1,4 +1,4 @@
-package createthread;
+package main.java.jvm.createthread;
 
 public class CreateByAnonymousClass {
 
diff --git a/src/createthread/CreateByCallable.java b/src/main/java/jvm/createthread/CreateByCallable.java
similarity index 94%
rename from src/createthread/CreateByCallable.java
rename to src/main/java/jvm/createthread/CreateByCallable.java
index 1fe5eba..d038c09 100644
--- a/src/createthread/CreateByCallable.java
+++ b/src/main/java/jvm/createthread/CreateByCallable.java
@@ -1,4 +1,4 @@
-package createthread;
+package main.java.jvm.createthread;
 
 import java.util.concurrent.Callable;
 import java.util.concurrent.FutureTask;
diff --git a/src/createthread/CreateByCompletableFuture.java b/src/main/java/jvm/createthread/CreateByCompletableFuture.java
similarity index 96%
rename from src/createthread/CreateByCompletableFuture.java
rename to src/main/java/jvm/createthread/CreateByCompletableFuture.java
index f4409c0..0c09314 100644
--- a/src/createthread/CreateByCompletableFuture.java
+++ b/src/main/java/jvm/createthread/CreateByCompletableFuture.java
@@ -1,4 +1,4 @@
-package createthread;
+package main.java.jvm.createthread;
 
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
diff --git a/src/createthread/CreateByExecutorService.java b/src/main/java/jvm/createthread/CreateByExecutorService.java
similarity index 94%
rename from src/createthread/CreateByExecutorService.java
rename to src/main/java/jvm/createthread/CreateByExecutorService.java
index 0f775b7..72f3de3 100644
--- a/src/createthread/CreateByExecutorService.java
+++ b/src/main/java/jvm/createthread/CreateByExecutorService.java
@@ -1,4 +1,4 @@
-package createthread;
+package main.java.jvm.createthread;
 
 import java.util.concurrent.*;
 
diff --git a/src/createthread/CreateByForkJoin.java b/src/main/java/jvm/createthread/CreateByForkJoin.java
similarity index 92%
rename from src/createthread/CreateByForkJoin.java
rename to src/main/java/jvm/createthread/CreateByForkJoin.java
index 5fd769d..ac1e6ad 100644
--- a/src/createthread/CreateByForkJoin.java
+++ b/src/main/java/jvm/createthread/CreateByForkJoin.java
@@ -1,4 +1,4 @@
-package createthread;
+package main.java.jvm.createthread;
 
 import java.util.Arrays;
 import java.util.List;
diff --git a/src/createthread/CreateByFutureTask.java b/src/main/java/jvm/createthread/CreateByFutureTask.java
similarity index 91%
rename from src/createthread/CreateByFutureTask.java
rename to src/main/java/jvm/createthread/CreateByFutureTask.java
index 1dcbfa3..973d233 100644
--- a/src/createthread/CreateByFutureTask.java
+++ b/src/main/java/jvm/createthread/CreateByFutureTask.java
@@ -1,4 +1,4 @@
-package createthread;
+package main.java.jvm.createthread;
 
 import java.util.concurrent.FutureTask;
 
diff --git a/src/createthread/CreateByRunnable.java b/src/main/java/jvm/createthread/CreateByRunnable.java
similarity index 90%
rename from src/createthread/CreateByRunnable.java
rename to src/main/java/jvm/createthread/CreateByRunnable.java
index 5948c5e..636dfeb 100644
--- a/src/createthread/CreateByRunnable.java
+++ b/src/main/java/jvm/createthread/CreateByRunnable.java
@@ -1,4 +1,4 @@
-package createthread;
+package main.java.jvm.createthread;
 
 public class CreateByRunnable implements Runnable{
     @Override
diff --git a/src/createthread/CreateByThread.java b/src/main/java/jvm/createthread/CreateByThread.java
similarity index 89%
rename from src/createthread/CreateByThread.java
rename to src/main/java/jvm/createthread/CreateByThread.java
index 5bab5b2..88ffb25 100644
--- a/src/createthread/CreateByThread.java
+++ b/src/main/java/jvm/createthread/CreateByThread.java
@@ -1,4 +1,4 @@
-package createthread;
+package main.java.jvm.createthread;
 
 public class CreateByThread extends Thread{
     @Override
diff --git a/src/createthread/CreateByThreadGroup.java b/src/main/java/jvm/createthread/CreateByThreadGroup.java
similarity index 93%
rename from src/createthread/CreateByThreadGroup.java
rename to src/main/java/jvm/createthread/CreateByThreadGroup.java
index 2c907d0..9ca8961 100644
--- a/src/createthread/CreateByThreadGroup.java
+++ b/src/main/java/jvm/createthread/CreateByThreadGroup.java
@@ -1,4 +1,4 @@
-package createthread;
+package main.java.jvm.createthread;
 
 public class CreateByThreadGroup {
 
diff --git a/src/createthread/CreateByTimer.java b/src/main/java/jvm/createthread/CreateByTimer.java
similarity index 91%
rename from src/createthread/CreateByTimer.java
rename to src/main/java/jvm/createthread/CreateByTimer.java
index b4222bb..706dd20 100644
--- a/src/createthread/CreateByTimer.java
+++ b/src/main/java/jvm/createthread/CreateByTimer.java
@@ -1,4 +1,4 @@
-package createthread;
+package main.java.jvm.createthread;
 
 import java.util.Timer;
 import java.util.TimerTask;
diff --git a/src/recursive/TreeNode.java b/src/main/java/recursive/TreeNode.java
similarity index 96%
rename from src/recursive/TreeNode.java
rename to src/main/java/recursive/TreeNode.java
index be85746..30b7814 100644
--- a/src/recursive/TreeNode.java
+++ b/src/main/java/recursive/TreeNode.java
@@ -1,4 +1,4 @@
-package recursive;
+package main.java.recursive;
 
 import java.util.ArrayList;
 import java.util.List;
diff --git a/src/recursive/TreeStructure.java b/src/main/java/recursive/TreeStructure.java
similarity index 97%
rename from src/recursive/TreeStructure.java
rename to src/main/java/recursive/TreeStructure.java
index 10fb3c0..ef848ca 100644
--- a/src/recursive/TreeStructure.java
+++ b/src/main/java/recursive/TreeStructure.java
@@ -1,4 +1,4 @@
-package recursive;
+package main.java.recursive;
 
 import java.util.*;