KT-4727 J2K: Convert Java code copied from browser or other sources

#KT-4727 Fixed

idea/testData/copyPaste/plainTextConversion/PostProcessing.txt

@@ -0,0 +1,15 @@
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+
+class JavaClass {
+    void foo(File file, List<String> target) {
+        ArrayList<String> list = new ArrayList<String>();
+        if (file != null) {
+            list.add(file.getName());
+        }
+        if (target != null) {
+            target.addAll(list);
+        }
+    }
+}