Merge remote-tracking branch 'eugenp/master'

core-java/src/main/java/com/baeldung/array/ArrayInverter.java

@@ -25,7 +25,9 @@ public class ArrayInverter {
     }
 
     public Object[] invertUsingStreams(final Object[] array) {
-        return IntStream.range(1, array.length + 1).mapToObj(i -> array[array.length - i]).toArray();
+        return IntStream.rangeClosed(1, array.length)
+            .mapToObj(i -> array[array.length - i])
+            .toArray();
     }
 
     public void invertUsingCommonsLang(Object[] array) {

core-java/src/test/java/com/baeldung/collection/WhenComparingTreeMapVsHashMap.java

@@ -0,0 +1,60 @@
+package com.baeldung.collection;
+
+import java.util.ConcurrentModificationException;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.TreeMap;
+
+import org.hamcrest.Matchers;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class WhenComparingTreeMapVsHashMap {
+
+    @Test
+    public void whenInsertObjectsTreeMap_thenNaturalOrder() {
+        Map<Integer, String> treemap = new TreeMap<>();
+        treemap.put(3, "TreeMap");
+        treemap.put(2, "vs");
+        treemap.put(1, "HashMap");
+        Assert.assertThat(treemap.keySet(), Matchers.contains(1, 2, 3));
+    }
+
+    @Test(expected = NullPointerException.class)
+    public void whenInsertNullInTreeMap_thenException() {
+        Map<Integer, String> treemap = new TreeMap<>();
+        treemap.put(null, "NullPointerException");
+    }
+
+    @Test
+    public void whenInsertObjectsHashMap_thenRandomOrder() {
+        Map<Integer, String> hashmap = new HashMap<>();
+        hashmap.put(3, "TreeMap");
+        hashmap.put(2, "vs");
+        hashmap.put(1, "HashMap");
+        Assert.assertThat(hashmap.keySet(), Matchers.containsInAnyOrder(1, 2, 3));
+    }
+
+    @Test
+    public void whenInsertNullInHashMap_thenInsertsNull() {
+        Map<Integer, String> hashmap = new HashMap<>();
+        hashmap.put(null, null);
+        Assert.assertNull(hashmap.get(null));
+    }
+
+    @Test
+    public void givenHashMapAndTreeMap_whenputDuplicates_thenOnlyUnique() {
+        Map<Integer, String> treeMap = new HashMap<>();
+        treeMap.put(1, "Baeldung");
+        treeMap.put(1, "Baeldung");
+
+        Assert.assertTrue(treeMap.size() == 1);
+
+        Map<Integer, String> treeMap2 = new TreeMap<>();
+        treeMap2.put(1, "Baeldung");
+        treeMap2.put(1, "Baeldung");
+
+        Assert.assertTrue(treeMap2.size() == 1);
+    }
+}

spring-cloud/spring-cloud-connectors-heroku/src/main/java/com/baeldung/spring/cloud/connectors/heroku/book/Book.java

@@ -0,0 +1,39 @@
+package com.baeldung.spring.cloud.connectors.heroku.book;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@Entity
+public class Book {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+    private String title;
+    private String author;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getAuthor() {
+        return author;
+    }
+
+    public void setAuthor(String author) {
+        this.author = author;
+    }
+}

spring-cloud/spring-cloud-connectors-heroku/src/main/java/com/baeldung/spring/cloud/connectors/heroku/book/BookController.java

@@ -0,0 +1,26 @@
+package com.baeldung.spring.cloud.connectors.heroku.book;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/books")
+public class BookController {
+
+    private final BookService bookService;
+
+    @Autowired
+    public BookController(BookService bookService) {
+        this.bookService = bookService;
+    }
+
+    @GetMapping("/{bookId}")
+    public Book findBook(@PathVariable Long bookId) {
+        return bookService.findBookById(bookId);
+    }
+
+    @PostMapping
+    public Book createBook(@RequestBody Book book) {
+        return bookService.createBook(book);
+    }
+}

spring-cloud/spring-cloud-connectors-heroku/src/main/java/com/baeldung/spring/cloud/connectors/heroku/book/BookRepository.java

@@ -0,0 +1,6 @@
+package com.baeldung.spring.cloud.connectors.heroku.book;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface BookRepository extends JpaRepository<Book, Long>{
+}

spring-cloud/spring-cloud-connectors-heroku/src/main/java/com/baeldung/spring/cloud/connectors/heroku/book/BookService.java

@@ -0,0 +1,29 @@
+package com.baeldung.spring.cloud.connectors.heroku.book;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Propagation;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@Transactional(readOnly = true)
+public class BookService {
+    private final BookRepository bookRepository;
+
+    @Autowired
+    public BookService(BookRepository bookRepository) {
+        this.bookRepository = bookRepository;
+    }
+
+    public Book findBookById(Long bookId) {
+        return bookRepository.findOne(bookId);
+    }
+
+    @Transactional(propagation = Propagation.REQUIRED)
+    public Book createBook(Book book) {
+        Book newBook = new Book();
+        newBook.setTitle(book.getTitle());
+        newBook.setAuthor(book.getAuthor());
+        return bookRepository.save(newBook);
+    }
+}

testing-modules/junit-5/src/test/java/com/baeldung/ExceptionUnitTest.java

@@ -3,7 +3,12 @@ package com.baeldung;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.util.ConcurrentModificationException;
+import java.util.HashMap;
+import java.util.Map;
+
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.function.Executable;
 
 public class ExceptionUnitTest {
 
@@ -22,4 +27,14 @@ public class ExceptionUnitTest {
             Integer.valueOf(str);
         });
     }
+
+    @Test
+    public void whenModifyMapDuringIteration_thenThrowExecption() {
+        Map<Integer, String> hashmap = new HashMap<>();
+        hashmap.put(1, "One");
+        hashmap.put(2, "Two");
+
+        Executable executable = () -> hashmap.forEach((key, value) -> hashmap.remove(1));
+        assertThrows(ConcurrentModificationException.class, executable);
+    }
 }