BAEL-1529 Intro to the Java SecurityManager (#7697)

core-java-modules/core-java-security-manager/pom.xml

@@ -0,0 +1,34 @@
+<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>
+    <artifactId>core-java-security-manager</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+    <name>core-java-security-manager</name>
+	
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+  
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>${maven.compiler.source}</source>
+                    <target>${maven.compiler.target}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+
+    </build>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+    </properties>
+</project>

core-java-modules/core-java-security-manager/src/main/java/com/baeldung/security/manager/CustomPermission.java

@@ -0,0 +1,13 @@
+package com.baeldung.security.manager;
+
+import java.security.BasicPermission;
+
+public class CustomPermission extends BasicPermission {
+    public CustomPermission(String name) {
+        super(name);
+    }
+
+    public CustomPermission(String name, String actions) {
+        super(name, actions);
+    }
+}

core-java-modules/core-java-security-manager/src/main/java/com/baeldung/security/manager/Service.java

@@ -0,0 +1,18 @@
+package com.baeldung.security.manager;
+
+public class Service {
+
+    public static final String OPERATION = "my-operation";
+
+    public void operation() {
+        SecurityManager securityManager = System.getSecurityManager();
+        if (securityManager != null) {
+            securityManager.checkPermission(new CustomPermission(OPERATION));
+        }
+        System.out.println("Operation is executed");
+    }
+
+    public static void main(String[] args) {
+        new Service().operation();
+    }
+}

core-java-modules/core-java-security-manager/src/test/java/com/baeldung/security/manager/SecurityManagerUnitTest.java

@@ -0,0 +1,35 @@
+package com.baeldung.security.manager;
+
+import org.junit.Test;
+
+import java.net.URL;
+import java.security.AccessControlException;
+import java.util.concurrent.Callable;
+
+public class SecurityManagerUnitTest {
+
+    @Test(expected = AccessControlException.class)
+    public void whenSecurityManagerIsActive_thenNetworkIsNotAccessibleByDefault() throws Exception {
+        doTest(() -> {
+            new URL("http://www.google.com").openConnection().connect();
+            return null;
+        });
+    }
+
+    @Test(expected = AccessControlException.class)
+    public void whenUnauthorizedClassTriesToAccessProtectedOperation_thenAnExceptionIsThrown() throws Exception {
+        doTest(() -> {
+            new Service().operation();
+            return null;
+        });
+    }
+
+    private void doTest(Callable<Void> action) throws Exception {
+        System.setSecurityManager(new SecurityManager());
+        try {
+            action.call();
+        } finally {
+            System.setSecurityManager(null);
+        }
+    }
+}

core-java-modules/pom.xml

@@ -19,6 +19,7 @@
         <module>core-java-optional</module>
         <module>core-java-lang-operators</module>
         <module>core-java-networking-2</module>
+        <module>core-java-security-manager</module>
     </modules>
     
 </project>