BAEL-5650 jar file path (#12463)

* BAEL-5650 jar file path

* move to jar module

core-java-modules/core-java-jar/src/main/java/com/baeldung/jarfile/JarFilePathResolver.java

@@ -0,0 +1,42 @@
+package com.baeldung.jarfile;
+
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.nio.file.Paths;
+
+public class JarFilePathResolver {
+
+    public String getJarFilePath(Class clazz) {
+        try {
+            return byGetProtectionDomain(clazz);
+        } catch (Exception e) {
+            // cannot get jar file path using byGetProtectionDomain
+            // Exception handling omitted
+        }
+        return byGetResource(clazz);
+    }
+
+    String byGetProtectionDomain(Class clazz) throws URISyntaxException {
+        URL url = clazz.getProtectionDomain().getCodeSource().getLocation();
+        return Paths.get(url.toURI()).toString();
+    }
+
+    String byGetResource(Class clazz) {
+        final URL classResource = clazz.getResource(clazz.getSimpleName() + ".class");
+        if (classResource == null) {
+            throw new RuntimeException("class resource is null");
+        }
+
+        final String url = classResource.toString();
+        if (url.startsWith("jar:file:")) {
+            // extract 'file:......jarName.jar' part from the url string
+            String path = url.replaceAll("^jar:(file:.*[.]jar)!/.*", "$1");
+            try {
+                return Paths.get(new URL(path).toURI()).toString();
+            } catch (Exception e) {
+                throw new RuntimeException("Invalid Jar File URL String");
+            }
+        }
+        throw new RuntimeException("Invalid Jar File URL String");
+    }
+}

core-java-modules/core-java-jar/src/test/java/com/baeldung/jarfile/JarFilePathResolverUnitTest.java

@@ -0,0 +1,55 @@
+package com.baeldung.jarfile;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.google.common.base.Ascii;
+import java.io.File;
+import java.net.URISyntaxException;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Spy;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+class JarFilePathResolverUnitTest {
+    @Spy
+    JarFilePathResolver jarFilePathResolver;
+
+    @Test
+    void givenClassObjectWhenCallingByGetProtectionDomainShouldGetExpectedPath() throws Exception {
+        String jarPath = jarFilePathResolver.byGetProtectionDomain(Ascii.class);
+        assertThat(jarPath).endsWith(".jar").contains("guava");
+        assertThat(new File(jarPath)).exists();
+    }
+
+    @Test
+    void givenClassObjectWhenCallingByGetResourceShouldGetExpectedPath() {
+        String jarPath = jarFilePathResolver.byGetResource(Ascii.class);
+        assertThat(jarPath).endsWith(".jar").contains("guava");
+        assertThat(new File(jarPath)).exists();
+    }
+
+    @Test
+    void givenClassObjectWhenNoSecurityExceptionRaisedShouldGetExpectedPath() throws URISyntaxException {
+        String jarPath = jarFilePathResolver.getJarFilePath(Ascii.class);
+        assertThat(jarPath).endsWith(".jar").contains("guava");
+        assertThat(new File(jarPath)).exists();
+        verify(jarFilePathResolver, times(1)).byGetProtectionDomain(Ascii.class);
+        verify(jarFilePathResolver, never()).byGetResource(Ascii.class);
+    }
+
+    @Test
+    void givenClassObjectWhenSecurityExceptionRaisedShouldGetExpectedPath() throws URISyntaxException {
+        when(jarFilePathResolver.byGetProtectionDomain(Ascii.class)).thenThrow(new SecurityException("not allowed"));
+        String jarPath = jarFilePathResolver.getJarFilePath(Ascii.class);
+        assertThat(jarPath).endsWith(".jar").contains("guava");
+        assertThat(new File(jarPath)).exists();
+        verify(jarFilePathResolver, times(1)).byGetProtectionDomain(Ascii.class);
+        verify(jarFilePathResolver, times(1)).byGetResource(Ascii.class);
+    }
+
+}