Updated code example and test case for mutex (#7642)

core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/mutex/SequenceGenerator.java

@@ -1,11 +1,12 @@
 package com.baeldung.concurrent.mutex;
 
 public class SequenceGenerator {
+
     private int currentValue = 0;
 
-    public int getNextSequence() throws InterruptedException {
+    public int getNextSequence() {
         currentValue = currentValue + 1;
-        Thread.sleep(500);
         return currentValue;
     }
+
 }

core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/mutex/SequenceGeneratorUsingMonitor.java

@@ -4,15 +4,16 @@ import com.google.common.util.concurrent.Monitor;
 
 public class SequenceGeneratorUsingMonitor extends SequenceGenerator {
 
-    private Monitor monitor = new Monitor();
+    private Monitor mutex = new Monitor();
 
     @Override
-    public int getNextSequence() throws InterruptedException {
-        monitor.enter();
+    public int getNextSequence() {
+        mutex.enter();
         try {
             return super.getNextSequence();
         } finally {
-            monitor.leave();
+            mutex.leave();
         }
     }
+
 }

core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/mutex/SequenceGeneratorUsingReentrantLock.java

@@ -7,7 +7,7 @@ public class SequenceGeneratorUsingReentrantLock extends SequenceGenerator {
     private ReentrantLock mutex = new ReentrantLock();
 
     @Override
-    public int getNextSequence() throws InterruptedException {
+    public int getNextSequence() {
         try {
             mutex.lock();
             return super.getNextSequence();
@@ -15,4 +15,5 @@ public class SequenceGeneratorUsingReentrantLock extends SequenceGenerator {
             mutex.unlock();
         }
     }
+
 }

core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/mutex/SequenceGeneratorUsingSemaphore.java

@@ -7,12 +7,15 @@ public class SequenceGeneratorUsingSemaphore extends SequenceGenerator {
     private Semaphore mutex = new Semaphore(1);
 
     @Override
-    public int getNextSequence() throws InterruptedException {
+    public int getNextSequence() {
         try {
             mutex.acquire();
             return super.getNextSequence();
+        } catch (InterruptedException e) {
+            throw new RuntimeException("Exception in critical section.", e);
         } finally {
             mutex.release();
         }
     }
+
 }

core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/mutex/SequenceGeneratorUsingSynchronizedBlock.java

@@ -2,9 +2,11 @@ package com.baeldung.concurrent.mutex;
 
 public class SequenceGeneratorUsingSynchronizedBlock extends SequenceGenerator {
 
+    private Object mutex = new Object();
+
     @Override
-    public int getNextSequence() throws InterruptedException {
-        synchronized (this) {
+    public int getNextSequence() {
+        synchronized (mutex) {
             return super.getNextSequence();
         }
     }

core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/mutex/SequenceGeneratorUsingSynchronizedMethod.java

@@ -3,7 +3,7 @@ package com.baeldung.concurrent.mutex;
 public class SequenceGeneratorUsingSynchronizedMethod extends SequenceGenerator {
 
     @Override
-    public synchronized int getNextSequence() throws InterruptedException {
+    public synchronized int getNextSequence() {
         return super.getNextSequence();
     }