[BAEL-4533] get class names from a jar

core-java-modules/core-java-jar/src/test/java/com/baeldung/jar/GetClassNamesFromJarUnitTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.jar;
+
+import com.google.common.collect.Sets;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.util.Arrays;
+import java.util.Objects;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+public class GetClassNamesFromJarUnitTest {
+    private static final String JAR_PATH = "example-jar/stripe-0.0.1-SNAPSHOT.jar";
+    private static final Set<String> EXPECTED_CLASS_NAMES = Sets.newHashSet(
+      "com.baeldung.stripe.StripeApplication",
+      "com.baeldung.stripe.ChargeRequest",
+      "com.baeldung.stripe.StripeService",
+      "com.baeldung.stripe.ChargeRequest$Currency",
+      "com.baeldung.stripe.ChargeController",
+      "com.baeldung.stripe.CheckoutController");
+
+    @Test
+    public void givenJarFilePath_whenLoadClassNames_thenGetClassNames() throws IOException, URISyntaxException {
+        File jarFile = new File(Objects.requireNonNull(getClass().getClassLoader().getResource(JAR_PATH)).toURI());
+        Set<String> classNames = GetClassNamesFromJar.getClassNamesFromJarFile(jarFile);
+        Assert.assertEquals(EXPECTED_CLASS_NAMES, classNames);
+    }
+
+    @Test
+    public void givenJarFilePath_whenLoadClass_thenGetClassObjects() throws IOException, ClassNotFoundException, URISyntaxException {
+        File jarFile = new File(Objects.requireNonNull(getClass().getClassLoader().getResource(JAR_PATH)).toURI());
+        Set<Class> classes = GetClassNamesFromJar.getClassesFromJarFile(jarFile);
+        Set<String> names = classes.stream().map(Class::getName).collect(Collectors.toSet());
+        Assert.assertEquals(EXPECTED_CLASS_NAMES, names);
+    }
+}