feat: added flexible constructor bodies

Author: claudioaltamura

src/main/java/de/claudioaltamura/java23/flexible_constructor_bodies/Child.java

@@ -0,0 +1,18 @@
+package de.claudioaltamura.java23.flexible_constructor_bodies;
+
+public class Child extends Parent {
+
+    private final int b;
+
+    public Child(int a, int b) {
+        //this is now allowed!
+        if(a < 0) throw new IllegalArgumentException("a must be => 0");
+        if(b < 0) throw new IllegalArgumentException("b must be => 0");
+        this.b = b;
+        super(a);
+    }
+
+    public int getB() {
+        return b;
+    }
+}

src/main/java/de/claudioaltamura/java23/flexible_constructor_bodies/Parent.java

@@ -0,0 +1,14 @@
+package de.claudioaltamura.java23.flexible_constructor_bodies;
+
+public class Parent {
+
+    private final int a;
+
+    public Parent(int a) {
+        this.a = a;
+    }
+
+    public int getA() {
+        return a;
+    }
+}

src/test/java/de/claudioaltamura/java23/flexible_constructor_bodies/ChildTest.java

@@ -0,0 +1,20 @@
+package de.claudioaltamura.java23.flexible_constructor_bodies;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class ChildTest {
+
+    @Test
+    void shouldCreateAChild() {
+        assertDoesNotThrow(() -> new Child(1,2));
+    }
+
+    @Test
+    void shouldNotCreateAChild() {
+        assertThrows(IllegalArgumentException.class, () -> new Child(-1,2));
+    }
+
+
+}