java 10 features (#4147)

core-java-10/src/test/java/com/baeldung/java10/Java10FeaturesUnitTest.java

@@ -0,0 +1,61 @@
+package com.baeldung.java10;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class Java10FeaturesUnitTest {
+
+    private List<Integer> someIntList;
+    
+    @Before
+    public void setup() {
+        someIntList = new ArrayList<>();
+        
+        someIntList.add(1);
+        someIntList.add(2);
+        someIntList.add(3);
+    }
+
+    @Test
+    public void whenVarInitWithString_thenGetStringTypeVar() {
+        var message = "Hello, Java 10";
+        assertTrue(message instanceof String);
+    }
+
+    @Test
+    public void whenVarInitWithAnonymous_thenGetAnonymousType() {
+        var obj = new Object() {};
+        assertFalse(obj.getClass().equals(Object.class));
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public void whenModifyCopyOfList_thenThrowsException() {
+        List<Integer> copyList = List.copyOf(someIntList);
+        copyList.add(4);
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public void whenModifyToUnmodifiableList_thenThrowsException() {
+        List<Integer> evenList = someIntList.stream()
+          .filter(i -> i % 2 == 0)
+          .collect(Collectors.toUnmodifiableList());
+        evenList.add(4);
+    }
+
+    @Test
+    public void whenListContainsInteger_OrElseThrowReturnsInteger() {
+        Integer firstEven = someIntList.stream()
+          .filter(i -> i % 2 == 0)
+          .findFirst()
+          .orElseThrow();
+        is(firstEven).equals(Integer.valueOf(2));
+    }
+}