Update test class for Java 14 ...

- samples only for standard features
- markdown javadoc for JEPs
- organize classes related to Java 14
- improve code readability

Author: mperor

src/test/java/pl/mperor/lab/java/Java12.java

@@ -16,24 +16,6 @@
  */
 public class Java12 {
 
-    @Test
-    public void testSwitchExpression() {
-        Assertions.assertEquals("Working Day", getTypeOfDayByNumber(1));
-        Assertions.assertEquals("Day Off", getTypeOfDayByNumber(6));
-        Assertions.assertThrows(IllegalStateException.class, () -> getTypeOfDayByNumber(0));
-    }
-
-    private String getTypeOfDayByNumber(int dayOfWeek) {
-        return switch (dayOfWeek) {
-            case 1, 2, 3, 4, 5 -> "Working Day";
-            case 6, 7 -> {
-                // code block example
-                yield "Day Off";
-            }
-            default -> throw new IllegalStateException("Unexpected value: " + dayOfWeek);
-        };
-    }
-
     @Test
     public void testStringIndentAndTransformMethods() {
         String text = "Hello\nJava 12\n";

src/test/java/pl/mperor/lab/java/Java14.java

@@ -3,19 +3,98 @@
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
-import java.util.Objects;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
-/**
- * Java 14 (March 2020)
- */
+/// Java 14™ (March 2020)
+/// [JDK 14](https://openjdk.org/projects/jdk/14)
+///
+/// - STANDARD FEATURES:
+///     - 361:	Switch Expressions (Standard)
+///     - 358:	Helpful NullPointerExceptions
+///     - 367:	Remove the Pack200 Tools and API
+///     - 345:	NUMA-Aware Memory Allocation for G1 (+XX:+UseNUMA)
+///     - 363:	Remove the Concurrent Mark Sweep (CMS) Garbage Collector (-XX:+UseConcMarkSweepGC)
+///     - 349:	JFR Event Streaming
+///     - 352:	Non-Volatile Mapped Byte Buffers
+///     - 364:	ZGC on macOS
+///     - 365:	ZGC on Windows
+///     - 362:	Deprecate the Solaris and SPARC Ports
+///     - 366:	Deprecate the ParallelScavenge + SerialOld GC Combination (-XX:-UseParallelOldGC)
+///
+/// - PREVIEW & INCUBATOR:
+///     - 359:	Records (Preview)
+///     - 305:	Pattern Matching for instanceof (Preview)
+///     - 368:	Text Blocks (Second Preview)
+///     - 343:	Packaging Tool 'jpackage' (Incubator)
+///     - 370:	Foreign-Memory Access API (Incubator)
 public class Java14 {
 
+    @Test
+    public void testSwitchExpression() {
+        Assertions.assertEquals("Working Day", getTypeOfDayByNumber(1));
+        Assertions.assertEquals("Day Off", getTypeOfDayByNumber(6));
+        Assertions.assertThrows(IllegalStateException.class, () -> getTypeOfDayByNumber(0));
+    }
+
+    private String getTypeOfDayByNumber(int dayOfWeek) {
+        return switch (dayOfWeek) {
+            case 1, 2, 3, 4, 5 -> "Working Day";
+            case 6, 7 -> {
+                // code block example
+                yield "Day Off";
+            }
+            default -> throw new IllegalStateException("Unexpected value: " + dayOfWeek);
+        };
+    }
+
+    @Test
+    public void testSwitchStatementVsSwitchExpression() {
+        assertTrue(switchExpression(Switch.EXPRESSION));
+        assertTrue(switchStatement(Switch.STATEMENT));
+    }
+
+    enum Switch {EXPRESSION, STATEMENT}
+
+    private static boolean switchExpression(Switch s) {
+        return switch (s) {
+            case EXPRESSION -> true;
+            default -> false;
+        };
+    }
+
+    private static boolean switchStatement(Switch s) {
+        switch (s) {
+            case STATEMENT -> {
+                return true;
+            }
+            default -> {
+                return false;
+            }
+        }
+    }
+
     @Test
     public void testHelpfulNullPointerExceptions() {
         NullPointerException exception = Assertions.assertThrows(NullPointerException.class, () -> {
             String name = null;
-            int length = name.length();
+            name.length();
+        });
+        assertTrue(exception.getMessage().contains("Cannot invoke \"String.length()\" because \"name\" is null"));
+    }
+
+    @Test
+    public void testPack200ToolsAndAPIRemoved() {
+        Assertions.assertThrows(ClassNotFoundException.class, () -> {
+            Class.forName("java.util.jar.Pack200");
         });
-        Assertions.assertTrue(exception.getMessage().contains("Cannot invoke \"String.length()\" because \"name\" is null"));
     }
+
+    @Test
+    public void testThreadIsInterruptedAlwaysAvailable() {
+        Thread neverStartedThread = new Thread();
+        Assertions.assertFalse(neverStartedThread.isInterrupted());
+        neverStartedThread.interrupt();
+        Assertions.assertTrue(neverStartedThread.isInterrupted());
+    }
+
 }

src/test/java/pl/mperor/lab/java/Java15.java

@@ -23,9 +23,9 @@
 ///     - 371:	Hidden Classes
 ///     - 372:	Remove the Nashorn JavaScript Engine
 ///     - 373:	Reimplement the Legacy DatagramSocket API
-///     - 374:	Disable and Deprecate Biased Locking
-///     - 377:	ZGC: A Scalable Low-Latency Garbage Collector
-///     - 379:	Shenandoah: A Low-Pause-Time Garbage Collector
+///     - 374:	Disable and Deprecate Biased Locking (-XX:+UseBiasedLocking)
+///     - 377:	ZGC: A Scalable Low-Latency Garbage Collector (-XX:+UseZGC)
+///     - 379:	Shenandoah: A Low-Pause-Time Garbage Collector (-XX:+UseShenandoahGC)
 ///     - 381:	Remove the Solaris and SPARC Ports
 ///     - 385:	Deprecate RMI Activation for Removal [Java17#testRmiActivationRemoved()]
 ///
@@ -44,8 +44,20 @@ public void testTextBlock() {
                     "password": "*****"
                 }
                 """;
-
         Assertions.assertTrue(json.contains("\"login\": \"admin\""));
+
+        String skippedLines = """
+                a\
+                b\
+                c\
+                """;
+        Assertions.assertEquals("abc", skippedLines);
+
+        String notSkippedSpaces = """
+                a \s
+                b\s
+                c""";
+        Assertions.assertEquals("a  \nb \nc", notSkippedSpaces);
     }
 
     @Test

src/test/java/pl/mperor/lab/java/Java16.java

@@ -28,7 +28,7 @@
 ///     - 395:	Records
 ///     - 394:	Pattern Matching for instanceof
 ///     - 390:	Warnings for Value-Based Classes
-///     - 392:	Packaging Tool
+///     - 392:	Packaging Tool 'jpackage'
 ///     - 380:	Unix-Domain Socket Channels
 ///     - 396:	Strongly Encapsulate JDK Internals by Default [Java17#testStronglyEncapsulatedInternals()]
 ///     - 376:	ZGC: Concurrent Thread-Stack Processing
@@ -46,7 +46,7 @@
 ///     - 338:	Vector API (Incubator)
 public class Java16 {
 
-    // POJOs
+    // POJOs with accessors (without getters)
     @Test
     public void testPairRecord() {
         var pair = Pair.of("Boy", "Girl");