[JVM] Add harness sample code for JVM test-to-harness approach

Signed-off-by: Arthur Chan <arthur.chan@adalogics.com>

llm_toolkit/prompt_builder.py

@@ -1368,16 +1368,24 @@ def build(self,
                                       language_text)
 
     if self.benchmark.language == 'jvm':
+      prompt_text = prompt_text.replace('{HEADER_FILE_LANG}', '')
+      prompt_text = prompt_text.replace('{HARNESS_HEADERS}', '')
+
       # Fuzz Introspector use JVM as it support other JVM languages in addition
       # to Java. Currently, the logic in OSS-Fuzz-Gen is only working on Java.
       prompt_text = prompt_text.replace('{PROG_LANG}', 'Java')
-      prompt_text = prompt_text.replace('{HEADER_FILE_LANG}', '')
 
       # Provide list of public classes of this project
       classes = introspector.query_introspector_public_classes(
           self.benchmark.project)
       prompt_text = prompt_text.replace('{PUBLIC_CLASSES}', ','.join(classes))
-      prompt_text = prompt_text.replace('{TARGET_SAMPLE_HARNESS}', '')
+
+      # Proivde sample harness code
+      harness_sample_text = ('There are already harnesses targeting this '
+                             'project, and an example of this is:\n'
+                             f'<code>\n{self.harness_source_code}\n</code>')
+      prompt_text = prompt_text.replace('{TARGET_SAMPLE_HARNESS}',
+                                        harness_sample_text)
     else:
       included_header_files = self.extract_header_files(test_source_code)
       if included_header_files:

prompts/template_xml/jvm_requirement_test_to_harness.txt

@@ -44,7 +44,7 @@ public class {HARNESS_NAME} {
 }
 </code></item>
 <item>
-Here is a comma-separated list of all publicly accessible classes in this project. You can use any of these classes, as well as classes from the JVM library. Please AVOID using other classes in the project, even if it exists in the following test or sample code as they are not publicly accessible.
+Here is a comma-separated list of all publicly accessible classes in this project. You can use any of these classes, as well as classes from the JVM library. Please AVOID using other classes in the project, even if it exists in the following test or sample code as they are not publicly accessible. Please import all necessary classes from this list.
 {PUBLIC_CLASSES}
 </item>
 <item>