Add val and var examples, unit tests and include flagUsage in lombok.config (#11419)

lombok/src/main/java/com/baeldung/lombok/valvar/ValExample.java

@@ -0,0 +1,45 @@
+package com.baeldung.lombok.valvar;
+
+import lombok.val;
+import lombok.var;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+
+public class ValExample {
+    public Class name() {
+        val name = "name";
+        System.out.println("Name: " + name);
+        return name.getClass();
+    }
+
+    public Class age() {
+        val age = Integer.valueOf(30);
+        System.out.println("Age: " + age);
+        return age.getClass();
+    }
+
+    public Class listOf() {
+        val agenda = new ArrayList<String>();
+        agenda.add("Day 1");
+        System.out.println("Agenda: " + agenda);
+        return agenda.getClass();
+    }
+
+    public Class mapOf() {
+        val books = new HashMap<Integer, String>();
+        books.put(1, "Book 1");
+        books.put(2, "Book 2");
+        System.out.println("Books:");
+        for (val entry : books.entrySet()) {
+            System.out.printf("- %d. %s\n", entry.getKey(), entry.getValue());
+        }
+        return books.getClass();
+    }
+
+    public Class compoundTypes(boolean isArray) {
+        val compound = isArray ? new ArrayList<String>() : new HashSet<String>();
+        return compound.getClass();
+    }
+}

lombok/src/main/java/com/baeldung/lombok/valvar/VarExample.java

@@ -0,0 +1,47 @@
+package com.baeldung.lombok.valvar;
+
+import lombok.var;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+public class VarExample {
+    public String name() {
+        var name = "name";
+        name = "newName";
+        System.out.println("Name: " + name);
+        return name;
+    }
+
+    public Integer age() {
+        var age = Integer.valueOf(30);
+        age = 35;
+        System.out.println("Age: " + age);
+        return age;
+    }
+
+    public ArrayList<String> listOf() {
+        var agenda = new ArrayList<String>();
+        agenda.add("Day 1");
+        agenda = new ArrayList<String>(Arrays.asList("Day 2"));
+        System.out.println("Agenda: " + agenda);
+        return agenda;
+    }
+
+    public Map<Integer, String> mapOf() {
+        var books = new HashMap<Integer, String>();
+        books.put(1, "Book 1");
+        books.put(2, "Book 2");
+        books = new HashMap<Integer, String>();
+        books.put(3, "Book 3");
+        books.put(4, "Book 4");
+
+        System.out.println("Books:");
+        for (var entry : books.entrySet()) {
+            System.out.printf("- %d. %s\n", entry.getKey(), entry.getValue());
+        }
+        return books;
+    }
+}

lombok/src/main/java/com/baeldung/lombok/valvar/lombok.config

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+lombok.var.flagUsage = warning
+lombok.val.flagUsage = warning

lombok/src/test/java/com/baeldung/lombok/valvar/ValExampleUnitTest.java

@@ -0,0 +1,24 @@
+package com.baeldung.lombok.valvar;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ValExampleUnitTest {
+
+    @Test
+    void whenUsingValWithString_thenTheAssignedClassIsCorrect() {
+        ValExample val = new ValExample();
+        assertThat(val.name()).isEqualTo(String.class);
+        assertThat(val.age()).isEqualTo(Integer.class);
+        assertThat(val.listOf()).isEqualTo(ArrayList.class);
+        assertThat(val.mapOf()).isEqualTo(HashMap.class);
+        assertThat(val.compoundTypes(true)).isEqualTo(ArrayList.class);
+        assertThat(val.compoundTypes(false)).isEqualTo(HashSet.class);
+    }
+
+}

lombok/src/test/java/com/baeldung/lombok/valvar/VarExampleUnitTest.java

@@ -0,0 +1,20 @@
+package com.baeldung.lombok.valvar;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.HashMap;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class VarExampleUnitTest {
+
+    @Test
+    void whenUsingVarWithString_thenTheAssignedClassIsCorrect() {
+        VarExample varExample = new VarExample();
+        assertThat(varExample.name()).isEqualTo("newName");
+        assertThat(varExample.age()).isEqualTo(35);
+        assertThat("Day 2").isIn(varExample.listOf());
+        assertThat(varExample.mapOf()).containsValue("Book 3");
+    }
+
+}