Deadlock & Starvation

Author: Ashleshk

Concurrency/007_deadlock_Part2/.idea/misc.xml

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+<?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://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

Concurrency/007_deadlock_Part2/.idea/modules.xml

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+public class Main {
+
+    public static void main(String[] args) {
+        final PolitePerson jane = new PolitePerson("Jane");
+        final PolitePerson john = new PolitePerson("John");
+
+        new Thread(new Runnable() {
+            @Override
+            public void run() {
+                jane.sayHello(john);
+            }
+        }).start();
+
+        new Thread(new Runnable() {
+            @Override
+            public void run() {
+                john.sayHello(jane);
+            }
+        }).start();
+    }
+
+    // 1. Thread1 acquires the lock on the jane object and enters the sayHello() method.
+    // It prints to the console, then suspends.
+    // 2. Thread2 acquires the lock on the john object and enters the sayHello() method.
+    // It prints to the console, then suspends.
+    // 3. Thread1 runs again and wants to say hello back to the john object. It tries to call the sayHelloBack() method
+    // using the john object that was passed into the sayHello() method,
+    // but Thread2 is holding the john lock, so Thread1 suspends.
+    // 4. Thread2 runs again and wants to say hello back to the jane object. It tries to call the sayHelloBack() method
+    // using the jane object that was passed into the sayHello() method,
+    // but Thread1 is holding the jane lock, so Thread2 suspends.
+
+    static class PolitePerson {
+        private final String name;
+
+        public PolitePerson(String name) {
+            this.name = name;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public synchronized void sayHello(PolitePerson person) {
+            System.out.format("%s: %s" + " has said hello to me!%n", this.name, person.getName());
+            person.sayHelloBack(this);
+        }
+
+        public synchronized void sayHelloBack(PolitePerson person) {
+            System.out.format("%s: %s" + " has said hello back to me!%n", this.name, person.getName());
+        }
+    }
+}