Refactor hashcode() samples (#2377)

core-java/src/main/java/com/baeldung/hashcode/application/Application.java

@@ -1,24 +0,0 @@
-package com.baeldung.hashcode.application;
-
-import java.util.HashMap;
-import java.util.Map;
-
-import com.baeldung.hashcode.entities.User;
-
-public class Application {
-
-    public static void main(String[] args) {
-        Map<User, User> users = new HashMap<>();
-        User user1 = new User(1L, "John", "john@domain.com");
-        User user2 = new User(2L, "Jennifer", "jennifer@domain.com");
-        User user3 = new User(3L, "Mary", "mary@domain.com");
-
-        users.put(user1, user1);
-        users.put(user2, user2);
-        users.put(user3, user3);
-
-        if (users.containsKey(user1)) {
-            System.out.print("User found in the collection");
-        }
-    }
-}

core-java/src/test/java/com/baeldung/hashcode/application/ApplicationTest.java

@@ -1,30 +1,30 @@
 package com.baeldung.hashcode.application;
 
+import com.baeldung.hashcode.entities.User;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import java.io.ByteArrayOutputStream;
 import java.io.PrintStream;
+import java.util.HashMap;
+import java.util.Map;
+
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 
 public class ApplicationTest {
 
-    private ByteArrayOutputStream outContent;
-
-    @Before
-    public void setUpPrintStreamInstance() throws Exception {
-        this.outContent = new ByteArrayOutputStream();
-        System.setOut(new PrintStream(outContent));
-    }
-
-    @After
-    public void tearDownByteArrayOutputStream() throws Exception {
-        outContent = null;
-    }
-
     @Test
     public void main_NoInputState_TextPrintedToConsole() throws Exception {
-        Application.main(new String[] {});
-        assertEquals("User found in the collection", outContent.toString());
+        Map<User, User> users = new HashMap<>();
+        User user1 = new User(1L, "John", "john@domain.com");
+        User user2 = new User(2L, "Jennifer", "jennifer@domain.com");
+        User user3 = new User(3L, "Mary", "mary@domain.com");
+
+        users.put(user1, user1);
+        users.put(user2, user2);
+        users.put(user3, user3);
+
+        assertTrue(users.containsKey(user1));
     }
 }