Delete existing class files to avoid JDK/IntelliJ bugs

#147 attempted
to do this but it only did it for Record Interface classes.
This commit does it for all classes that are to be generated.
Ad hoc testing shows that it solves the problem.

Fixes #139

record-builder-processor/src/main/java/io/soabase/recordbuilder/processor/RecordBuilderProcessor.java

@@ -31,7 +31,10 @@
 import javax.lang.model.element.PackageElement;
 import javax.lang.model.element.TypeElement;
 import javax.tools.Diagnostic;
+import javax.tools.FileObject;
 import javax.tools.JavaFileObject;
+import javax.tools.StandardLocation;
+import java.io.File;
 import java.io.IOException;
 import java.io.Writer;
 import java.util.Optional;
@@ -218,6 +221,7 @@ private void writeRecordBuilderJavaFile(TypeElement record, String packageName,
         try {
             String fullyQualifiedName = packageName.isEmpty() ? builderClassType.name()
                     : (packageName + "." + builderClassType.name());
+            deletePossibleClassFile(packageName, builderClassType.name());
             JavaFileObject sourceFile = filer.createSourceFile(fullyQualifiedName);
             try (Writer writer = sourceFile.openWriter()) {
                 javaFile.writeTo(writer);
@@ -235,6 +239,7 @@ private void writeRecordInterfaceJavaFile(TypeElement element, String packageNam
 
         Filer filer = processingEnv.getFiler();
         try {
+            deletePossibleClassFile(packageName, classType.name());
             String fullyQualifiedName = packageName.isEmpty() ? classType.name()
                     : (packageName + "." + classType.name());
             JavaFileObject sourceFile = filer.createSourceFile(fullyQualifiedName);
@@ -263,4 +268,22 @@ private void handleWriteError(TypeElement element, IOException e) {
         }
         processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, message, element);
     }
+
+    private void deletePossibleClassFile(String packageName, String className) {
+        try {
+            className += ".class";
+
+            FileObject resource = processingEnv.getFiler().getResource(StandardLocation.CLASS_OUTPUT, packageName,
+                    className);
+            File file = new File(resource.toUri());
+            if (file.exists()) {
+                if (!file.delete()) {
+                    processingEnv.getMessager().printMessage(Diagnostic.Kind.MANDATORY_WARNING,
+                            "Could not delete existing class file: %s".formatted(file));
+                }
+            }
+        } catch (IOException e) {
+            // ignore
+        }
+    }
 }