Refactor XLint options for better handling of null/empty lists.

src/main/java/rife/bld/operations/JavacOptions.java

@@ -13,6 +13,7 @@ import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.stream.Collectors;
 
 import static rife.bld.operations.CompileOperation.COMPILE_OPTION_MODULE_PATH;
 
@@ -848,8 +849,7 @@ public class JavacOptions extends ArrayList<String> {
      * @since 2.3.1
      */
     public JavacOptions xLint(List<XLintKey> keys) {
-        add("-Xlint:" + StringUtils.join(keys, ",").replaceAll("_", "-").toLowerCase());
-        return this;
+        return addXLintOption(keys, "");
     }
 
     /**
@@ -868,7 +868,21 @@ public class JavacOptions extends ArrayList<String> {
      * @since 2.3.1
      */
     public JavacOptions xLintDisable(List<XLintKey> keys) {
-        add("-Xlint:-" + StringUtils.join(keys, ",-").replaceAll("_", "-").toLowerCase());
+        return addXLintOption(keys, "-");
+    }
+
+
+    private JavacOptions addXLintOption(List<XLintKey> keys, String prefix) {
+        if (keys == null || keys.isEmpty()) {
+            return this;
+        }
+
+        var formattedKeys = keys.stream()
+                .map(key -> prefix + key.name().replace('_', '-').toLowerCase())
+                .collect(Collectors.joining(",", "-Xlint:", ""));
+
+        add(formattedKeys);
         return this;
     }
+
 }

src/test/java/rife/bld/operations/TestJavacOptions.java

@@ -781,8 +781,14 @@ class TestJavacOptions {
             List<XLintKey> emptyList = List.of();
             options.xLintDisable(emptyList);
 
-            assertEquals(1, options.size());
-            assertEquals("-Xlint:-", options.get(0));
+            assertEquals(0, options.size());
+        }
+
+        @Test
+        void testXLintDisableNullList() {
+            options.xLintDisable((List<XLintKey>) null);
+
+            assertEquals(0, options.size());
         }
 
         @Test
@@ -829,8 +835,7 @@ class TestJavacOptions {
             List<XLintKey> emptyList = List.of();
             options.xLint(emptyList);
 
-            assertEquals(1, options.size());
-            assertEquals("-Xlint:", options.get(0));
+            assertEquals(0, options.size());
         }
 
         @Test
@@ -852,6 +857,12 @@ class TestJavacOptions {
             assertTrue(options.contains("-Xlint:none"));
         }
 
+        @Test
+        void testXLintNullList() {
+            options.xLint((List<XLintKey>) null);
+            assertEquals(0, options.size());
+        }
+
         @Test
         void testXLintReturnsThis() {
             var result = options.xLint();