diff --git a/codeflash/languages/java/instrumentation.py b/codeflash/languages/java/instrumentation.py
index 18fdb1409..0bb2515a3 100644
--- a/codeflash/languages/java/instrumentation.py
+++ b/codeflash/languages/java/instrumentation.py
@@ -16,6 +16,7 @@
 
 import logging
 import re
+from bisect import bisect_right
 from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
@@ -230,10 +231,8 @@ def _collect_calls(node, wrapper_bytes, body_bytes, prefix_len, func_name, analy
 
 def _byte_to_line_index(byte_offset: int, line_byte_starts: list[int]) -> int:
     """Map a byte offset in body_text to a body_lines index."""
-    for i in range(len(line_byte_starts) - 1, -1, -1):
-        if byte_offset >= line_byte_starts[i]:
-            return i
-    return 0
+    idx = bisect_right(line_byte_starts, byte_offset) - 1
+    return max(idx, 0)
 
 
 def _infer_array_cast_type(line: str) -> str | None: