Working but facing unhandled exception

PoolThreadProject/PersonalThreadPool/.idea/compiler.xml

+<?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="PersonalThreadPool" />
+      </profile>
+    </annotationProcessing>
+  </component>
+</project>
\ No newline at end of file

PoolThreadProject/PersonalThreadPool/.idea/encodings.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding">
+    <file url="file://$PROJECT_DIR$/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/src/main/resources" charset="UTF-8" />
+  </component>
+</project>
\ No newline at end of file

PoolThreadProject/PersonalThreadPool/.idea/jarRepositories.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RemoteRepositoriesConfiguration">
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Central Repository" />
+      <option name="url" value="https://repo.maven.apache.org/maven2" />
+    </remote-repository>
+    <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>
+  </component>
+</project>
\ No newline at end of file

PoolThreadProject/PersonalThreadPool/.idea/misc.xml

+<?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_1_8" default="true" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>
\ No newline at end of file

PoolThreadProject/PersonalThreadPool/.idea/vcs.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file

PoolThreadProject/PersonalThreadPool/.idea/workspace.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="AutoImportSettings">
+    <option name="autoReloadType" value="SELECTIVE" />
+  </component>
+  <component name="ChangeListManager">
+    <list default="true" id="00b47615-8913-4160-9c73-190821c9c0e9" name="Changes" comment="">
+      <change afterPath="$PROJECT_DIR$/.idea/encodings.xml" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/.idea/misc.xml" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/.idea/vcs.xml" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/pom.xml" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/src/main/java/Main.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/src/main/java/MyThreadPool.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/src/main/java/MyThreadPoolRunnable.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/src/main/java/TasksQueue.java" afterDir="false" />
+    </list>
+    <option name="SHOW_DIALOG" value="false" />
+    <option name="HIGHLIGHT_CONFLICTS" value="true" />
+    <option name="HIGHLIGHT_NON_ACTIVE_CHANGELIST" value="false" />
+    <option name="LAST_RESOLUTION" value="IGNORE" />
+  </component>
+  <component name="FileTemplateManagerImpl">
+    <option name="RECENT_TEMPLATES">
+      <list>
+        <option value="Class" />
+      </list>
+    </option>
+  </component>
+  <component name="Git.Settings">
+    <option name="RECENT_GIT_ROOT_PATH" value="$PROJECT_DIR$" />
+  </component>
+  <component name="MarkdownSettingsMigration">
+    <option name="stateVersion" value="1" />
+  </component>
+  <component name="ProjectId" id="2YfRg5HWBulipBOuD9eFp0wMKb0" />
+  <component name="ProjectLevelVcsManager" settingsEditedManually="true">
+    <ConfirmationsSetting value="2" id="Add" />
+  </component>
+  <component name="ProjectViewState">
+    <option name="hideEmptyMiddlePackages" value="true" />
+    <option name="showLibraryContents" value="true" />
+  </component>
+  <component name="PropertiesComponent"><![CDATA[{
+  "keyToString": {
+    "RunOnceActivity.OpenProjectViewOnStart": "true",
+    "RunOnceActivity.ShowReadmeOnStart": "true",
+    "SHARE_PROJECT_CONFIGURATION_FILES": "true"
+  }
+}]]></component>
+  <component name="SpellCheckerSettings" RuntimeDictionaries="0" Folders="0" CustomDictionaries="0" DefaultDictionary="application-level" UseSingleDictionary="true" transferred="true" />
+  <component name="TaskManager">
+    <task active="true" id="Default" summary="Default task">
+      <changelist id="00b47615-8913-4160-9c73-190821c9c0e9" name="Changes" comment="" />
+      <created>1700914756140</created>
+      <option name="number" value="Default" />
+      <option name="presentableId" value="Default" />
+      <updated>1700914756140</updated>
+    </task>
+    <servers />
+  </component>
+  <component name="Vcs.Log.Tabs.Properties">
+    <option name="TAB_STATES">
+      <map>
+        <entry key="MAIN">
+          <value>
+            <State />
+          </value>
+        </entry>
+      </map>
+    </option>
+  </component>
+</project>
\ No newline at end of file

PoolThreadProject/PersonalThreadPool/pom.xml

+<?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>org.example</groupId>
+    <artifactId>PersonalThreadPool</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>8</maven.compiler.source>
+        <maven.compiler.target>8</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+</project>
\ No newline at end of file

PoolThreadProject/PersonalThreadPool/src/main/java/Main.java

+public class Main
+{
+    public static void main(String[] args) throws Exception
+    {
+        MyThreadPool myThreadPool = new MyThreadPool<>(3 , 50);
+        for(int i = 0; i < 100; i++)
+        {
+            int taskNo = i;
+            myThreadPool.execute(new Runnable() {
+                @Override
+                public void run() {
+                    String message = Thread.currentThread().getName() + ": Task " + (taskNo + 1) ;
+                    System.out.println(message);
+                }
+            });
+        }
+       /* myThreadPool.waitUntilAllTasksFinished(1000);
+        myThreadPool.stop();*/
+
+    }
+}

PoolThreadProject/PersonalThreadPool/src/main/java/MyThreadPool.java

+
+import java.util.ArrayList;
+import java.util.List;
+
+public class MyThreadPool <RunnableType extends Runnable>
+{
+    private TasksQueue<RunnableType> tasksQueue;
+
+    private List<MyThreadPoolRunnable> workingThreads;
+
+    private boolean isTerminated;
+    private boolean allowInserting;
+
+    private int queueSize;
+    private int workingThreadsNumber;
+
+    public MyThreadPool(int queueSizeInput, int workingThreadsNumberInput) throws Exception
+    {
+        if (queueSizeInput <=0 || workingThreadsNumberInput <= 0)
+        {
+            throw new Exception("Queue Size and Threads Number must be Strictly Larger than zero!!");
+        }
+        this.queueSize = queueSizeInput;
+        this.workingThreadsNumber = workingThreadsNumberInput;
+        this.isTerminated = false;
+        this.allowInserting = true;
+        initiateThreadPool();
+        startWorking();
+    }
+
+    public void execute (RunnableType runnableType) throws Exception
+    {
+        if (isTerminated || !allowInserting) return;
+        this.tasksQueue.addTask(runnableType);
+    }
+
+    public void stop()
+    {
+        synchronized (this)
+        {
+            this.isTerminated = true;
+            this.allowInserting = false;
+            for (MyThreadPoolRunnable runnable : workingThreads)
+                runnable.forceStop();
+        }
+    }
+
+    public synchronized void waitUntilAllTasksFinished(long timeOut) throws InterruptedException
+    {
+        if (this.isTerminated) return;
+        allowInserting = false;
+        this.isTerminated = true;
+        tasksQueue.softFinish(timeOut);
+
+    }
+
+    private void initiateThreadPool()
+    {
+        this.tasksQueue = new TasksQueue<>(this.queueSize);
+
+        this.workingThreads = new ArrayList<>();
+
+        for (int i=1 ; i<= this.workingThreadsNumber ; i++)
+        {
+            workingThreads.add(new MyThreadPoolRunnable(tasksQueue));
+        }
+    }
+
+    private void startWorking()
+    {
+        for (MyThreadPoolRunnable myThreadPoolRunnable : workingThreads)
+            new Thread(myThreadPoolRunnable).start();
+    }
+}

PoolThreadProject/PersonalThreadPool/src/main/java/MyThreadPoolRunnable.java

+public class MyThreadPoolRunnable<RunnableType extends Runnable> implements Runnable
+{
+    private TasksQueue<RunnableType> tasksQueue;
+
+    private boolean isTerminated;
+
+    private Thread thread;
+
+    public MyThreadPoolRunnable(TasksQueue<RunnableType> tasksQueue)
+    {
+        this.tasksQueue = tasksQueue;
+        this.isTerminated = false;
+    }
+
+    public void forceStop()
+    {
+        this.isTerminated = true;
+        this.thread.interrupt();
+    }
+
+    @Override
+    public void run()
+    {
+        thread = Thread.currentThread();
+
+        while(!terminated())
+        {
+            try
+            {
+                RunnableType job = tasksQueue.removeTask();
+                if (job == null) continue;
+                job.run();
+            }
+            catch (InterruptedException e)
+            {
+                //ignore
+            }
+        }
+    }
+
+    private synchronized boolean terminated()
+    {
+        return this.isTerminated;
+    }
+}

PoolThreadProject/PersonalThreadPool/src/main/java/TasksQueue.java

+
+import java.util.ArrayList;
+import java.util.List;
+
+public class TasksQueue <RunnableType>
+{
+    private List<RunnableType> tasks;
+    private int maxSize;
+
+    private boolean allowInsertion;
+    public TasksQueue(int maxCap)
+    {
+        this.maxSize = maxCap;
+        tasks = new ArrayList<>();
+        allowInsertion = true;
+    }
+
+    public void addTask(RunnableType task) throws Exception
+    {
+        if (task == null)
+        {
+            throw new Exception("Task Assigned is NULL");
+        }
+        synchronized (this)
+        {
+            if (!allowInsertion) return;
+            if (tasks.size() == maxSize)
+            {
+                ///System.out.println("Stuck in Adding");
+                this.wait();
+            }
+            tasks.add(task);
+            this.notifyAll();
+        }
+    }
+
+    public RunnableType removeTask () throws InterruptedException
+    {
+        RunnableType task = null;
+        synchronized (this)
+        {
+            if (tasks.size()==0 && allowInsertion)
+            {
+                ///System.out.println("Stuck in Removing");
+                this.wait();
+            }
+            if (tasks.size() ==0 && !allowInsertion) return task;
+            if(tasks.size() == 0)
+            {
+                /*System.out.println("HHHHHHHHHHHH");
+                System.out.println("!allow" + !allowInsertion);*/
+            }
+            task = tasks.remove(0);
+            this.notifyAll();
+        }
+        return task;
+    }
+
+    public void softFinish(long timeOut) throws InterruptedException
+    {
+            allowInsertion = false;
+            while (this.size() > 0)
+            {
+                this.wait(timeOut);
+            }
+    }
+
+    private int size()
+    {
+        synchronized (tasks)
+        {
+            return tasks.size();
+        }
+    }
+}