[record-field-reflection] Get All Record Fields and Its Values via Reflection (#14933)

core-java-modules/core-java-17/src/test/java/com/baeldung/recordproperties/ReadRecordPropertiesByReflectionUnitTest.java

@@ -0,0 +1,89 @@
+package com.baeldung.recordproperties;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.RecordComponent;
+import java.util.ArrayList;
+
+import org.junit.jupiter.api.Test;
+
+record Player(String name, int age, Long score) {
+}
+
+public class ReadRecordPropertiesByReflectionUnitTest {
+    private static final Player ERIC = new Player("Eric", 28, 4242L);
+
+    @Test
+    void whenUsingRecordComponent_thenGetExpectedResult() {
+        var fields = new ArrayList<Field>();
+        RecordComponent[] components = Player.class.getRecordComponents();
+        for (var comp : components) {
+            try {
+                Field field = ERIC.getClass()
+                  .getDeclaredField(comp.getName());
+                field.setAccessible(true);
+                fields.add(field);
+            } catch (NoSuchFieldException e) {
+                // for simplicity, error handling is skipped
+            }
+        }
+
+        assertEquals(3, fields.size());
+
+        var nameField = fields.get(0);
+        var ageField = fields.get(1);
+        var scoreField = fields.get(2);
+        try {
+            assertEquals("name", nameField.getName());
+            assertEquals(String.class, nameField.getType());
+            assertEquals("Eric", nameField.get(ERIC));
+
+            assertEquals("age", ageField.getName());
+            assertEquals(int.class, ageField.getType());
+            assertEquals(28, ageField.get(ERIC));
+
+            assertEquals("score", scoreField.getName());
+            assertEquals(Long.class, scoreField.getType());
+            assertEquals(4242L, scoreField.get(ERIC));
+        } catch (IllegalAccessException exception) {
+            // for simplicity, error handling is skipped
+        }
+
+    }
+
+    @Test
+    void whenUsingClassGetDeclaredField_thenGetExpectedResult() {
+        // record has no public fields
+        assertEquals(0, Player.class.getFields().length);
+
+        var fields = new ArrayList<Field>();
+        for (var field : Player.class.getDeclaredFields()) {
+            field.setAccessible(true);
+            fields.add(field);
+        }
+
+        assertEquals(3, fields.size());
+        var nameField = fields.get(0);
+        var ageField = fields.get(1);
+        var scoreField = fields.get(2);
+
+        try {
+            assertEquals("name", nameField.getName());
+            assertEquals(String.class, nameField.getType());
+            assertEquals("Eric", nameField.get(ERIC));
+
+            assertEquals("age", ageField.getName());
+            assertEquals(int.class, ageField.getType());
+            assertEquals(28, ageField.get(ERIC));
+
+            assertEquals("score", scoreField.getName());
+            assertEquals(Long.class, scoreField.getType());
+            assertEquals(4242L, scoreField.get(ERIC));
+        } catch (IllegalAccessException ex) {
+            // for simplicity, error handling is skipped
+        }
+
+    }
+
+}