initial

src/pp.02.01-MemoryBarrier/README.md

@@ -0,0 +1,7 @@
+# Laboraufgabe "Anwendung von Memory Barrieren"
+- [Aufgabenstellung](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/labs/02-01-MemoryBarrier.html)
+- [Musterlösung](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/labs/02-Solutions.html#laboraufgabe-anwendung-von-memory-barrieren)
+
+# Materialien
+- [Folien](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/slides/02-konkurrierenderZugriff.html)
+- [Skript](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/notes/02-konkurrierenderZugriff.html)

src/pp.02.01-MemoryBarrier/justfile

@@ -0,0 +1,12 @@
+default:
+    mvn clean compile exec:java
+exec args:
+    mvn exec:java -Dexec.args={{args}}
+clean:
+    mvn clean
+compile:
+    mvn compile
+test:
+    mvn test
+javadoc:
+    mvn javadoc:javadoc

src/pp.02.01-MemoryBarrier/pom.xml

@@ -0,0 +1,61 @@
+<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>pp</groupId>
+  <artifactId>pp.02.01-MemoryBarrier</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <packaging>jar</packaging>
+
+  <properties>
+    <exec.mainClass>pp.MemoryBarrierTest</exec.mainClass>
+    <maven.compiler.release>10</maven.compiler.release>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+  <dependencies>
+    <dependency><!-- für Unit-Tests -->
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter</artifactId>
+      <version>5.10.0</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency><!-- für Lombok -->
+      <groupId>org.projectlombok</groupId>
+      <artifactId>lombok</artifactId>
+      <version>1.18.30</version>
+      <scope>provided</scope>
+    </dependency>
+    <dependency><!-- für net.jcip Annotationen -->
+      <groupId>net.jcip</groupId>
+      <artifactId>jcip-annotations</artifactId>
+      <version>1.0</version>
+      <scope>provided</scope>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin><!-- für Unit-Tests [mvn test] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>3.0.0</version>
+      </plugin>
+      <plugin><!-- [mvn compile] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.9.0</version>
+      </plugin>
+      <plugin><!-- [mvn exec:java] -->
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>exec-maven-plugin</artifactId>
+        <version>3.1.0</version>
+      </plugin>
+      <plugin><!-- [mvn javadoc:javadoc] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-javadoc-plugin</artifactId>
+        <version>3.5.0</version>
+        <configuration>
+          <show>private</show>
+          <locale>en_US</locale>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>

src/pp.02.01-MemoryBarrier/src/main/java/pp/MemoryBarrierTest.java

@@ -0,0 +1,24 @@
+package pp;
+
+public class MemoryBarrierTest extends Thread {
+
+    public boolean stopped = false;
+
+    @Override
+    public void run() {
+        while (!this.stopped) {
+            // work
+        }
+        System.out.println("MemoryBarrierTest-Thread actually stopped.");
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var t = new MemoryBarrierTest();
+        t.start();
+        Thread.sleep(1000);
+        t.stopped = true;
+        System.out.println(
+                "Main thread set stopped on MemoryBarrierTest-Thread.");
+    }
+
+}

src/pp.02.01-MemoryBarrier_solution/README.md

@@ -0,0 +1,7 @@
+# Laboraufgabe "Anwendung von Memory Barrieren"
+- [Aufgabenstellung](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/labs/02-01-MemoryBarrier.html)
+- [Musterlösung](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/labs/02-Solutions.html#laboraufgabe-anwendung-von-memory-barrieren)
+
+# Materialien
+- [Folien](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/slides/02-konkurrierenderZugriff.html)
+- [Skript](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/notes/02-konkurrierenderZugriff.html)

src/pp.02.01-MemoryBarrier_solution/justfile

@@ -0,0 +1,25 @@
+default:
+    mvn clean compile exec:java
+exec args:
+    mvn exec:java -Dexec.args={{args}}
+clean:
+    mvn clean
+compile:
+    mvn compile
+test:
+    mvn test
+javadoc:
+    mvn javadoc:javadoc
+
+_exec class: clean compile
+    mvn exec:java -Dexec.mainClass="pp.{{class}}" -Dexec.args=""
+MemoryBarrierTest1:
+    just _exec MemoryBarrierTest1
+MemoryBarrierTest1b:
+    just _exec MemoryBarrierTest1b
+MemoryBarrierTest2:
+    just _exec MemoryBarrierTest2
+MemoryBarrierTest5:
+    just _exec MemoryBarrierTest5
+MemoryBarrierTest6:
+    just _exec MemoryBarrierTest6

src/pp.02.01-MemoryBarrier_solution/pom.xml

@@ -0,0 +1,61 @@
+<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>pp</groupId>
+  <artifactId>pp.02.01-MemoryBarrier_solution</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <packaging>jar</packaging>
+
+  <properties>
+    <exec.mainClass>pp.MemoryBarrierTest1</exec.mainClass>
+    <maven.compiler.release>10</maven.compiler.release>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+  <dependencies>
+    <dependency><!-- für Unit-Tests -->
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter</artifactId>
+      <version>5.10.0</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency><!-- für Lombok -->
+      <groupId>org.projectlombok</groupId>
+      <artifactId>lombok</artifactId>
+      <version>1.18.30</version>
+      <scope>provided</scope>
+    </dependency>
+    <dependency><!-- für net.jcip Annotationen -->
+      <groupId>net.jcip</groupId>
+      <artifactId>jcip-annotations</artifactId>
+      <version>1.0</version>
+      <scope>provided</scope>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin><!-- für Unit-Tests [mvn test] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>3.0.0</version>
+      </plugin>
+      <plugin><!-- [mvn compile] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.9.0</version>
+      </plugin>
+      <plugin><!-- [mvn exec:java] -->
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>exec-maven-plugin</artifactId>
+        <version>3.1.0</version>
+      </plugin>
+      <plugin><!-- [mvn javadoc:javadoc] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-javadoc-plugin</artifactId>
+        <version>3.5.0</version>
+        <configuration>
+          <show>private</show>
+          <locale>en_US</locale>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>

src/pp.02.01-MemoryBarrier_solution/src/main/java/pp/MemoryBarrierTest1.java

@@ -0,0 +1,26 @@
+package pp;
+
+public class MemoryBarrierTest1 extends Thread {
+
+    // Markierung von stopped als volatile => Jede Änderung wirkt als
+    // Memory-Barrier
+    public volatile boolean stopped = false;
+
+    @Override
+    public void run() {
+        while (!this.stopped) {
+            // work
+        }
+        System.out.println("MemoryBarrierTest-Thread actually stopped.");
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var t = new MemoryBarrierTest1();
+        t.start();
+        Thread.sleep(1000);
+        t.stopped = true;
+        System.out.println(
+                "Main thread set stopped on MemoryBarrierTest-Thread.");
+    }
+
+}

src/pp.02.01-MemoryBarrier_solution/src/main/java/pp/MemoryBarrierTest1b.java

@@ -0,0 +1,36 @@
+package pp;
+
+public class MemoryBarrierTest1b extends Thread {
+
+    private boolean stopped = false;
+
+    // lesende Zugriffe auf this.stopped über synchronized Getter => wirkt als
+    // Memory-Barrier (Pull)
+    public synchronized boolean getStopped() {
+        return this.stopped;
+    }
+
+    // ändernde Zugriffe auf this.stopped über synchronized Setter => wirkt als
+    // Memory-Barrier (Push)
+    public synchronized void setStopped(boolean stopped) {
+        this.stopped = stopped;
+    }
+
+    @Override
+    public void run() {
+        while (!getStopped()) {
+            // work
+        }
+        System.out.println("MemoryBarrierTest-Thread actually stopped.");
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var t = new MemoryBarrierTest1b();
+        t.start();
+        Thread.sleep(1000);
+        t.setStopped(true);
+        System.out.println(
+                "Main thread set stopped on MemoryBarrierTest-Thread.");
+    }
+
+}

src/pp.02.01-MemoryBarrier_solution/src/main/java/pp/MemoryBarrierTest2.java

@@ -0,0 +1,28 @@
+package pp;
+
+public class MemoryBarrierTest2 extends Thread {
+
+    public boolean stopped = false;
+
+    @Override
+    public void run() {
+        while (!this.stopped) {
+            // jedes synchronized wirkt als Memory-Barrier
+            // work
+            synchronized (this) {
+                //
+            }
+        }
+        System.out.println("MemoryBarrierTest-Thread actually stopped.");
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var t = new MemoryBarrierTest2();
+        t.start();
+        Thread.sleep(1000);
+        t.stopped = true;
+        System.out.println(
+                "Main thread set stopped on MemoryBarrierTest-Thread.");
+    }
+
+}

src/pp.02.01-MemoryBarrier_solution/src/main/java/pp/MemoryBarrierTest5.java

@@ -0,0 +1,46 @@
+package pp;
+
+public class MemoryBarrierTest5 extends Thread {
+
+    public boolean stopped = false;
+    private Thread stopper;
+
+    public void startStopper() {
+        this.stopper = new Thread(() -> {
+            try {
+                Thread.sleep(1000);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
+            this.stopped = true;
+            System.out.println(
+                    "Stopper thread set stopped on MemoryBarrierTest-Thread.");
+        });
+        this.stopper.start();
+    }
+
+    @Override
+    public void run() {
+        startStopper();
+        while (!this.stopped) {
+            // work
+            if (this.stopper != null) {
+                try {
+                    // Synchronisierung von Stopper-Thread Variablenänderungen
+                    // durch Warten auf das Ende von Stopper Thread
+                    this.stopper.join(1);
+                } catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                }
+            }
+        }
+        System.out.println("MemoryBarrierTest-Thread actually stopped.");
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var t = new MemoryBarrierTest5();
+        t.start();
+
+    }
+
+}

src/pp.02.01-MemoryBarrier_solution/src/main/java/pp/MemoryBarrierTest6.java

@@ -0,0 +1,30 @@
+package pp;
+
+public class MemoryBarrierTest6 extends Thread {
+
+    public boolean stopped = false;
+
+    @Override
+    public void run() {
+        while (!this.stopped) {
+            // work
+            // wg. Zustandswechsel
+            try {
+                Thread.sleep(1);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
+        }
+        System.out.println("MemoryBarrierTest-Thread actually stopped.");
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var t = new MemoryBarrierTest6();
+        t.start();
+        Thread.sleep(1000);
+        t.stopped = true;
+        System.out.println(
+                "Main thread set stopped on MemoryBarrierTest-Thread.");
+    }
+
+}

src/pp.02.02-ThreadLocal/README.md

@@ -0,0 +1,7 @@
+# Laboraufgabe "threadlokaler Speicher"
+- [Aufgabenstellung](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/labs/02-02-ThreadLocal.html)
+- [Musterlösung](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/labs/02-Solutions.html#laboraufgabe-threadlokaler-speicher)
+
+# Materialien
+- [Folien](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/slides/02-konkurrierenderZugriff.html)
+- [Skript](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/notes/02-konkurrierenderZugriff.html)

src/pp.02.02-ThreadLocal/justfile

@@ -0,0 +1,12 @@
+default:
+    mvn clean compile exec:java
+exec args:
+    mvn exec:java -Dexec.args={{args}}
+clean:
+    mvn clean
+compile:
+    mvn compile
+test:
+    mvn test
+javadoc:
+    mvn javadoc:javadoc

src/pp.02.02-ThreadLocal/pom.xml

@@ -0,0 +1,61 @@
+<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>pp</groupId>
+  <artifactId>pp.02.02-ThreadLocal</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <packaging>jar</packaging>
+
+  <properties>
+    <exec.mainClass>pp.MyThreadLocalRandom</exec.mainClass>
+    <maven.compiler.release>10</maven.compiler.release>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+  <dependencies>
+    <dependency><!-- für Unit-Tests -->
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter</artifactId>
+      <version>5.10.0</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency><!-- für Lombok -->
+      <groupId>org.projectlombok</groupId>
+      <artifactId>lombok</artifactId>
+      <version>1.18.30</version>
+      <scope>provided</scope>
+    </dependency>
+    <dependency><!-- für net.jcip Annotationen -->
+      <groupId>net.jcip</groupId>
+      <artifactId>jcip-annotations</artifactId>
+      <version>1.0</version>
+      <scope>provided</scope>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin><!-- für Unit-Tests [mvn test] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>3.0.0</version>
+      </plugin>
+      <plugin><!-- [mvn compile] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.9.0</version>
+      </plugin>
+      <plugin><!-- [mvn exec:java] -->
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>exec-maven-plugin</artifactId>
+        <version>3.1.0</version>
+      </plugin>
+      <plugin><!-- [mvn javadoc:javadoc] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-javadoc-plugin</artifactId>
+        <version>3.5.0</version>
+        <configuration>
+          <show>private</show>
+          <locale>en_US</locale>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>

src/pp.02.02-ThreadLocal/src/main/java/pp/MyThreadLocalRandom.java

@@ -0,0 +1,26 @@
+package pp;
+
+import java.util.Random;
+
+public class MyThreadLocalRandom implements Runnable {
+
+    public static long now = System.currentTimeMillis();
+    public Random rand = new Random(now);
+
+    @Override
+    public void run() {
+        var strBuf = new StringBuffer();
+        strBuf.append(Thread.currentThread().getName() + ": ");
+        for (var j = 0; j < 20; j++) {
+            strBuf.append(String.format("%2d ", this.rand.nextInt(100)));
+        }
+        System.out.println(strBuf);
+    }
+
+    public static void main(String... args) {
+        var runner = new MyThreadLocalRandom();
+        for (var i = 0; i < 10; i++) {
+            new Thread(runner, String.format("Runner-%02d", i)).start();
+        }
+    }
+}

src/pp.02.02-ThreadLocal_solution/README.md

@@ -0,0 +1,7 @@
+# Laboraufgabe "threadlokaler Speicher"
+- [Aufgabenstellung](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/labs/02-02-ThreadLocal.html)
+- [Musterlösung](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/labs/02-Solutions.html#laboraufgabe-threadlokaler-speicher)
+
+# Materialien
+- [Folien](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/slides/02-konkurrierenderZugriff.html)
+- [Skript](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/notes/02-konkurrierenderZugriff.html)

src/pp.02.02-ThreadLocal_solution/justfile

@@ -0,0 +1,25 @@
+default:
+    mvn clean compile exec:java
+exec args:
+    mvn exec:java -Dexec.args={{args}}
+clean:
+    mvn clean
+compile:
+    mvn compile
+test:
+    mvn test
+javadoc:
+    mvn javadoc:javadoc
+
+_exec class: clean compile
+    mvn exec:java -Dexec.mainClass="pp.{{class}}" -Dexec.args=""
+MyThreadLocalRandom0:
+    just _exec MyThreadLocalRandom0
+MyThreadLocalRandom1:
+    just _exec MyThreadLocalRandom1
+MyThreadLocalRandom2:
+    just _exec MyThreadLocalRandom2
+MyThreadLocalRandom3:
+    just _exec MyThreadLocalRandom3
+MyThreadLocalRandom4:
+    just _exec MyThreadLocalRandom4

src/pp.02.02-ThreadLocal_solution/pom.xml

@@ -0,0 +1,61 @@
+<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>pp</groupId>
+  <artifactId>pp.02.02-ThreadLocal_solution</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <packaging>jar</packaging>
+
+  <properties>
+    <exec.mainClass>pp.MyThreadLocalRandom0</exec.mainClass>
+    <maven.compiler.release>10</maven.compiler.release>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+  <dependencies>
+    <dependency><!-- für Unit-Tests -->
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter</artifactId>
+      <version>5.10.0</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency><!-- für Lombok -->
+      <groupId>org.projectlombok</groupId>
+      <artifactId>lombok</artifactId>
+      <version>1.18.30</version>
+      <scope>provided</scope>
+    </dependency>
+    <dependency><!-- für net.jcip Annotationen -->
+      <groupId>net.jcip</groupId>
+      <artifactId>jcip-annotations</artifactId>
+      <version>1.0</version>
+      <scope>provided</scope>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin><!-- für Unit-Tests [mvn test] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>3.0.0</version>
+      </plugin>
+      <plugin><!-- [mvn compile] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.9.0</version>
+      </plugin>
+      <plugin><!-- [mvn exec:java] -->
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>exec-maven-plugin</artifactId>
+        <version>3.1.0</version>
+      </plugin>
+      <plugin><!-- [mvn javadoc:javadoc] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-javadoc-plugin</artifactId>
+        <version>3.5.0</version>
+        <configuration>
+          <show>private</show>
+          <locale>en_US</locale>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>

src/pp.02.02-ThreadLocal_solution/src/main/java/pp/MyThreadLocalRandom0.java

@@ -0,0 +1,25 @@
+package pp;
+
+import java.util.Random;
+
+public class MyThreadLocalRandom0 implements Runnable {
+    public static long now = System.currentTimeMillis();
+    public Random rand = new Random(now);
+
+    @Override
+    public void run() {
+        var strBuf = new StringBuffer();
+        strBuf.append(Thread.currentThread().getName() + ": ");
+        for (var j = 0; j < 20; j++) {
+            strBuf.append(String.format("%02d ", this.rand.nextInt(100)));
+        }
+        System.out.println(strBuf);
+    }
+
+    public static void main(String... args) {
+        var runner = new MyThreadLocalRandom0();
+        for (var i = 0; i < 10; i++) {
+            new Thread(runner, String.format("Runner-%02d", i)).start();
+        }
+    }
+}

src/pp.02.02-ThreadLocal_solution/src/main/java/pp/MyThreadLocalRandom1.java

@@ -0,0 +1,30 @@
+package pp;
+
+import java.util.Random;
+
+public class MyThreadLocalRandom1 implements Runnable {
+    public static long now = System.currentTimeMillis();
+    public ThreadLocal<Random> rand = new ThreadLocal<>() {
+        @Override
+        protected Random initialValue() {
+            return new Random(now);
+        }
+    };
+
+    @Override
+    public void run() {
+        var strBuf = new StringBuffer();
+        strBuf.append(Thread.currentThread().getName() + ": ");
+        for (var j = 0; j < 20; j++) {
+            strBuf.append(String.format("%02d ", this.rand.get().nextInt(100)));
+        }
+        System.out.println(strBuf);
+    }
+
+    public static void main(String... args) {
+        var runner = new MyThreadLocalRandom1();
+        for (var i = 0; i < 10; i++) {
+            new Thread(runner, String.format("Runner-%02d", i)).start();
+        }
+    }
+}

src/pp.02.02-ThreadLocal_solution/src/main/java/pp/MyThreadLocalRandom2.java

@@ -0,0 +1,30 @@
+package pp;
+
+import java.util.Random;
+
+public class MyThreadLocalRandom2 implements Runnable {
+    public static long now = System.currentTimeMillis();
+    public static ThreadLocal<Random> rand = new ThreadLocal<>() {
+        @Override
+        protected Random initialValue() {
+            return new Random(now);
+        }
+    };
+
+    @Override
+    public void run() {
+        var strBuf = new StringBuffer();
+        strBuf.append(Thread.currentThread().getName() + ": ");
+        for (var j = 0; j < 20; j++) {
+            strBuf.append(String.format("%02d ", rand.get().nextInt(100)));
+        }
+        System.out.println(strBuf);
+    }
+
+    public static void main(String... args) {
+        var runner = new MyThreadLocalRandom2();
+        for (var i = 0; i < 10; i++) {
+            new Thread(runner, String.format("Runner-%02d", i)).start();
+        }
+    }
+}

src/pp.02.02-ThreadLocal_solution/src/main/java/pp/MyThreadLocalRandom3.java

@@ -0,0 +1,28 @@
+package pp;
+
+import java.util.Random;
+import java.util.concurrent.ThreadLocalRandom;
+
+public class MyThreadLocalRandom3 implements Runnable {
+
+    public static Random rand = ThreadLocalRandom.current();
+
+    @Override
+    public void run() {
+        var strBuf = new StringBuffer();
+        strBuf.append(Thread.currentThread().getName() + ": ");
+        for (var j = 0; j < 20; j++) {
+            synchronized (MyThreadLocalRandom3.class) {
+                strBuf.append(String.format("%02d ", rand.nextInt(100)));
+            }
+        }
+        System.out.println(strBuf);
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var runner = new MyThreadLocalRandom3();
+        for (var i = 0; i < 10; i++) {
+            new Thread(runner, String.format("Runner-%02d", i)).start();
+        }
+    }
+}

src/pp.02.02-ThreadLocal_solution/src/main/java/pp/MyThreadLocalRandom4.java

@@ -0,0 +1,28 @@
+package pp;
+
+import java.util.Random;
+import java.util.concurrent.ThreadLocalRandom;
+
+public class MyThreadLocalRandom4 implements Runnable {
+
+    public Random rand = ThreadLocalRandom.current();
+
+    @Override
+    public void run() {
+        var strBuf = new StringBuffer();
+        strBuf.append(Thread.currentThread().getName() + ": ");
+        for (var j = 0; j < 20; j++) {
+            synchronized (MyThreadLocalRandom4.class) {
+                strBuf.append(String.format("%02d ", this.rand.nextInt(100)));
+            }
+        }
+        System.out.println(strBuf);
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var runner = new MyThreadLocalRandom4();
+        for (var i = 0; i < 10; i++) {
+            new Thread(runner, String.format("Runner-%02d", i)).start();
+        }
+    }
+}

src/pp.02.03-Lock/README.md

@@ -0,0 +1,7 @@
+# Laboraufgabe "gegenseitiger Ausschluss"
+- [Aufgabenstellung](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/labs/02-03-Lock.html)
+- [Musterlösung](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/labs/02-Solutions.html#laboraufgabe-gegenseitiger-ausschluss)
+
+# Materialien
+- [Folien](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/slides/02-konkurrierenderZugriff.html)
+- [Skript](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/notes/02-konkurrierenderZugriff.html)

src/pp.02.03-Lock/justfile

@@ -0,0 +1,17 @@
+default:
+    mvn clean compile exec:java
+exec args:
+    mvn exec:java -Dexec.args={{args}}
+clean:
+    mvn clean
+compile:
+    mvn compile
+test:
+    mvn test
+javadoc:
+    mvn javadoc:javadoc
+
+_exec factory: clean compile
+    mvn exec:java -Dexec.mainClass="pp.{{factory}}" -Dexec.args=""
+Factory:
+    just _exec Factory

src/pp.02.03-Lock/pom.xml

@@ -0,0 +1,61 @@
+<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>pp</groupId>
+  <artifactId>pp.02.03-Lock</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <packaging>jar</packaging>
+
+  <properties>
+    <exec.mainClass>pp.Factory</exec.mainClass>
+    <maven.compiler.release>10</maven.compiler.release>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+  <dependencies>
+    <dependency><!-- für Unit-Tests -->
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter</artifactId>
+      <version>5.10.0</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency><!-- für Lombok -->
+      <groupId>org.projectlombok</groupId>
+      <artifactId>lombok</artifactId>
+      <version>1.18.30</version>
+      <scope>provided</scope>
+    </dependency>
+    <dependency><!-- für net.jcip Annotationen -->
+      <groupId>net.jcip</groupId>
+      <artifactId>jcip-annotations</artifactId>
+      <version>1.0</version>
+      <scope>provided</scope>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin><!-- für Unit-Tests [mvn test] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>3.0.0</version>
+      </plugin>
+      <plugin><!-- [mvn compile] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.9.0</version>
+      </plugin>
+      <plugin><!-- [mvn exec:java] -->
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>exec-maven-plugin</artifactId>
+        <version>3.1.0</version>
+      </plugin>
+      <plugin><!-- [mvn javadoc:javadoc] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-javadoc-plugin</artifactId>
+        <version>3.5.0</version>
+        <configuration>
+          <show>private</show>
+          <locale>en_US</locale>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>

src/pp.02.03-Lock/src/main/java/pp/Factory.java

@@ -0,0 +1,39 @@
+package pp;
+
+public class Factory {
+
+    private static Type instance;
+    private static Object lock = new Object();
+
+    public static Type getInstance() {
+        Type.prepare();
+        if (instance == null) {
+            instance = new Type();
+        }
+        return instance;
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var now = System.currentTimeMillis();
+        var threads = new Thread[100];
+        for (var i = 0; i < 100; i++) {
+            threads[i] = new Thread(
+                () -> {
+                    Type object = Factory.getInstance();
+                    System.out.println(
+                        Thread.currentThread().getName() +
+                        ": serial of instance = " +
+                        object.getSerial()
+                    );
+                },
+                String.format("InstanceGrabber-%02d", i)
+            );
+            threads[i].start();
+        }
+        for (var i = 0; i < 100; i++) {
+            threads[i].join();
+        }
+        var time = System.currentTimeMillis() - now;
+        System.out.println("Dauer: " + time + "ms");
+    }
+}

src/pp.02.03-Lock/src/main/java/pp/Type.java

@@ -0,0 +1,38 @@
+package pp;
+
+import net.jcip.annotations.*;
+
+@ThreadSafe
+public final class Type {
+
+    private static int counter = 0;
+    private int serial = 0;
+    private int number = 0;
+
+    public static void prepare() {
+        try {
+            Thread.sleep(500);
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+    }
+
+    public Type() {
+        synchronized (Type.class) {
+            Type.counter++;
+            this.serial = Type.counter;
+        }
+    }
+
+    public synchronized int getNumber() {
+        return this.number;
+    }
+
+    public synchronized void setNumber(int number) {
+        this.number = number;
+    }
+
+    public synchronized int getSerial() {
+        return this.serial;
+    }
+}

src/pp.02.03-Lock_solution/README.md

@@ -0,0 +1,7 @@
+# Laboraufgabe "gegenseitiger Ausschluss"
+- [Aufgabenstellung](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/labs/02-03-Lock.html)
+- [Musterlösung](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/labs/02-Solutions.html#laboraufgabe-gegenseitiger-ausschluss)
+
+# Materialien
+- [Folien](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/slides/02-konkurrierenderZugriff.html)
+- [Skript](https://services.informatik.hs-mannheim.de/~s.leuchter/pp/notes/02-konkurrierenderZugriff.html)

src/pp.02.03-Lock_solution/justfile

@@ -0,0 +1,25 @@
+default:
+    mvn clean compile exec:java
+exec args:
+    mvn exec:java -Dexec.args={{args}}
+clean:
+    mvn clean
+compile:
+    mvn compile
+test:
+    mvn test
+javadoc:
+    mvn javadoc:javadoc
+
+_exec class: clean compile
+    mvn exec:java -Dexec.mainClass="pp.{{class}}" -Dexec.args=""
+Factory0:
+    just _exec Factory0
+Factory1:
+    just _exec Factory1
+Factory2:
+    just _exec Factory2
+Factory3:
+    just _exec Factory3
+Factory4:
+    just _exec Factory4

src/pp.02.03-Lock_solution/pom.xml

@@ -0,0 +1,61 @@
+<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>pp</groupId>
+  <artifactId>pp.02.03-Lock_solution</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <packaging>jar</packaging>
+
+  <properties>
+    <exec.mainClass>pp.Factory0</exec.mainClass>
+    <maven.compiler.release>10</maven.compiler.release>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+  <dependencies>
+    <dependency><!-- für Unit-Tests -->
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter</artifactId>
+      <version>5.10.0</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency><!-- für Lombok -->
+      <groupId>org.projectlombok</groupId>
+      <artifactId>lombok</artifactId>
+      <version>1.18.30</version>
+      <scope>provided</scope>
+    </dependency>
+    <dependency><!-- für net.jcip Annotationen -->
+      <groupId>net.jcip</groupId>
+      <artifactId>jcip-annotations</artifactId>
+      <version>1.0</version>
+      <scope>provided</scope>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin><!-- für Unit-Tests [mvn test] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>3.0.0</version>
+      </plugin>
+      <plugin><!-- [mvn compile] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.9.0</version>
+      </plugin>
+      <plugin><!-- [mvn exec:java] -->
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>exec-maven-plugin</artifactId>
+        <version>3.1.0</version>
+      </plugin>
+      <plugin><!-- [mvn javadoc:javadoc] -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-javadoc-plugin</artifactId>
+        <version>3.5.0</version>
+        <configuration>
+          <show>private</show>
+          <locale>en_US</locale>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>

src/pp.02.03-Lock_solution/src/main/java/pp/Factory0.java

@@ -0,0 +1,38 @@
+package pp;
+
+public class Factory0 {
+
+    private static Type instance;
+
+    public static Type getInstance() {
+        Type.prepare();
+        if (instance == null) {
+            instance = new Type();
+        }
+        return instance;
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var now = System.currentTimeMillis();
+        var threads = new Thread[100];
+        for (var i = 0; i < 100; i++) {
+            threads[i] = new Thread(
+                () -> {
+                    var object = getInstance();
+                    System.out.println(
+                        Thread.currentThread().getName() +
+                        ": serial of instance = " +
+                        object.getSerial()
+                    );
+                },
+                String.format("InstanceGrabber-%02d", i)
+            );
+            threads[i].start();
+        }
+        for (var i = 0; i < 100; i++) {
+            threads[i].join();
+        }
+        var time = System.currentTimeMillis() - now;
+        System.out.println("Dauer: " + time + "ms");
+    }
+}

src/pp.02.03-Lock_solution/src/main/java/pp/Factory1.java

@@ -0,0 +1,38 @@
+package pp;
+
+public class Factory1 {
+
+    private static Type instance;
+
+    public static synchronized Type getInstance() {
+        Type.prepare();
+        if (instance == null) {
+            instance = new Type();
+        }
+        return instance;
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var now = System.currentTimeMillis();
+        var threads = new Thread[100];
+        for (var i = 0; i < 100; i++) {
+            threads[i] = new Thread(
+                () -> {
+                    var object = getInstance();
+                    System.out.println(
+                        Thread.currentThread().getName() +
+                        ": serial of instance = " +
+                        object.getSerial()
+                    );
+                },
+                String.format("InstanceGrabber-%02d", i)
+            );
+            threads[i].start();
+        }
+        for (var i = 0; i < 100; i++) {
+            threads[i].join();
+        }
+        var time = System.currentTimeMillis() - now;
+        System.out.println("Dauer: " + time + "ms");
+    }
+}

src/pp.02.03-Lock_solution/src/main/java/pp/Factory2.java

@@ -0,0 +1,40 @@
+package pp;
+
+public class Factory2 {
+
+    private static volatile Type instance;
+
+    public static Type getInstance() {
+        Type.prepare();
+        synchronized (Factory2.class) {
+            if (instance == null) {
+                instance = new Type();
+            }
+        }
+        return instance;
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var now = System.currentTimeMillis();
+        var threads = new Thread[100];
+        for (var i = 0; i < 100; i++) {
+            threads[i] = new Thread(
+                () -> {
+                    var object = getInstance();
+                    System.out.println(
+                        Thread.currentThread().getName() +
+                        ": serial of instance = " +
+                        object.getSerial()
+                    );
+                },
+                String.format("InstanceGrabber-%02d", i)
+            );
+            threads[i].start();
+        }
+        for (var i = 0; i < 100; i++) {
+            threads[i].join();
+        }
+        var time = System.currentTimeMillis() - now;
+        System.out.println("Dauer: " + time + "ms");
+    }
+}

src/pp.02.03-Lock_solution/src/main/java/pp/Factory3.java

@@ -0,0 +1,41 @@
+package pp;
+
+public class Factory3 {
+
+    private static volatile Type instance;
+    private static Object lock = new Object();
+
+    public static Type getInstance() {
+        Type.prepare();
+        synchronized (lock) {
+            if (instance == null) {
+                instance = new Type();
+            }
+        }
+        return instance;
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var now = System.currentTimeMillis();
+        var threads = new Thread[100];
+        for (var i = 0; i < 100; i++) {
+            threads[i] = new Thread(
+                () -> {
+                    var object = Factory3.getInstance();
+                    System.out.println(
+                        Thread.currentThread().getName() +
+                        ": serial of instance = " +
+                        object.getSerial()
+                    );
+                },
+                String.format("InstanceGrabber-%02d", i)
+            );
+            threads[i].start();
+        }
+        for (var i = 0; i < 100; i++) {
+            threads[i].join();
+        }
+        var time = System.currentTimeMillis() - now;
+        System.out.println("Dauer: " + time + "ms");
+    }
+}

src/pp.02.03-Lock_solution/src/main/java/pp/Factory4.java

@@ -0,0 +1,42 @@
+package pp;
+
+public class Factory4 {
+
+    private static volatile Type instance;
+
+    public static Type getInstance() {
+        Type.prepare();
+        if (instance == null) {
+            synchronized (Factory4.class) {
+                if (instance == null) {
+                    instance = new Type();
+                }
+            }
+        }
+        return instance;
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        var now = System.currentTimeMillis();
+        var threads = new Thread[100];
+        for (var i = 0; i < 100; i++) {
+            threads[i] = new Thread(
+                () -> {
+                    var object = getInstance();
+                    System.out.println(
+                        Thread.currentThread().getName() +
+                        ": serial of instance = " +
+                        object.getSerial()
+                    );
+                },
+                String.format("InstanceGrabber-%02d", i)
+            );
+            threads[i].start();
+        }
+        for (var i = 0; i < 100; i++) {
+            threads[i].join();
+        }
+        var time = System.currentTimeMillis() - now;
+        System.out.println("Dauer: " + time + "ms");
+    }
+}

src/pp.02.03-Lock_solution/src/main/java/pp/Type.java

@@ -0,0 +1,38 @@
+package pp;
+
+import net.jcip.annotations.*;
+
+@ThreadSafe
+public final class Type {
+
+    private static int counter = 0;
+    private int serial = 0;
+    private int number = 0;
+
+    public static void prepare() {
+        try {
+            Thread.sleep(500);
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+    }
+
+    public Type() {
+        synchronized (Type.class) {
+            Type.counter++;
+            this.serial = Type.counter;
+        }
+    }
+
+    public synchronized int getNumber() {
+        return this.number;
+    }
+
+    public synchronized void setNumber(int number) {
+        this.number = number;
+    }
+
+    public synchronized int getSerial() {
+        return this.serial;
+    }
+}