diff --git a/infer/src/dune.in b/infer/src/dune.in
index 76bad75c3..e60af4a80 100644
--- a/infer/src/dune.in
+++ b/infer/src/dune.in
@@ -129,6 +129,8 @@ let topl_stanzas =
   ["(ocamllex ToplLexer)"; "(menhir (flags --unused-token INDENT --explain) (modules ToplParser))"]
 
 
+let java_sources_lexer = if java then ["(ocamllex jSourceFileInfo)"] else []
+
 let flatten_sources_stanzas =
   List.map
     (fun source_dir ->
@@ -143,7 +145,7 @@ let flatten_sources_stanzas =
 (** The build stanzas to be passed to dune *)
 let stanzas =
   (env_stanza :: main_lib_stanza :: infer_exe_stanza :: infertop_stanza :: clang_lexer_stanzas)
-  @ topl_stanzas @ flatten_sources_stanzas
+  @ java_sources_lexer @ topl_stanzas @ flatten_sources_stanzas
 
 
 ;;
diff --git a/infer/src/java/jFrontend.ml b/infer/src/java/jFrontend.ml
index 8553f2246..894859f34 100644
--- a/infer/src/java/jFrontend.ml
+++ b/infer/src/java/jFrontend.ml
@@ -132,12 +132,31 @@ let cache_classname cn =
 
 let is_classname_cached cn = Sys.file_exists (path_of_cached_classname cn) = `Yes
 
+let test_source_file_location source_file program cn node =
+  let is_synthetic = function
+    | Javalib.JInterface _ ->
+        false
+    | Javalib.JClass jc ->
+        jc.Javalib.c_synthetic
+  in
+  if not (is_synthetic node) then
+    match JClasspath.get_java_location program cn with
+    | None ->
+        L.(debug Capture Verbose)
+          "WARNING SOURCE FILE PARSER: location not found for class %s in source file %s \n"
+          (JBasics.cn_name cn)
+          (SourceFile.to_abs_path source_file)
+    | Some _ ->
+        ()
+
+
 (* Given a source file and a class, translates the code of this class.
    In init - mode, finds out whether this class contains initializers at all,
    in this case translates it. In standard mode, all methods are translated *)
 let create_icfg source_file program tenv icfg cn node =
   L.(debug Capture Verbose) "\tclassname: %s@." (JBasics.cn_name cn) ;
   if Config.dependency_mode && not (is_classname_cached cn) then cache_classname cn ;
+  test_source_file_location source_file program cn node ;
   let translate m =
     let proc_name = JTransType.translate_method_name program tenv m in
     JClasspath.set_callee_translated program proc_name ;
@@ -194,19 +213,8 @@ let compute_source_icfg program tenv source_basename package_opt source_file =
   let select test procedure cn node =
     if test node then try procedure cn node with Bir.Subroutine -> ()
   in
-  let set_java_location cn _node =
-    let cn_name = JBasics.cn_name cn in
-    let loc = JSourceFileInfo.class_name_location source_file cn_name in
-    L.debug Capture Verbose "set_java_location %s with location %a@." cn_name Location.pp_file_pos
-      loc ;
-    JClasspath.set_java_location program cn loc
-  in
   (* we must set the java location for all classes in the source file before translation *)
-  let () =
-    JBasics.ClassMap.iter
-      (select (should_capture program package_opt source_basename) set_java_location)
-      (JClasspath.get_classmap program)
-  in
+  JSourceFileInfo.collect_class_location program source_file ;
   let () =
     JBasics.ClassMap.iter
       (select
diff --git a/infer/src/java/jSourceFileInfo.ml b/infer/src/java/jSourceFileInfo.ml
deleted file mode 100644
index 56a5a1c35..000000000
--- a/infer/src/java/jSourceFileInfo.ml
+++ /dev/null
@@ -1,13 +0,0 @@
-(*
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *)
-
-open! IStd
-
-(** this is a naive/temporary implementation in a near diff, we will 1) parse the source file to
-    collect location datas for all class names 2) cache the result for later uses but we may have to
-    adapt a litle some signatures *)
-let class_name_location file _cn : Location.t = {line= 0; col= 0; file}
diff --git a/infer/src/java/jSourceFileInfo.mli b/infer/src/java/jSourceFileInfo.mli
deleted file mode 100644
index b05a009ae..000000000
--- a/infer/src/java/jSourceFileInfo.mli
+++ /dev/null
@@ -1,12 +0,0 @@
-(*
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *)
-
-open! IStd
-
-val class_name_location : SourceFile.t -> string -> Location.t
-(** [class_name_location source class_name] searches in file [source] the declaration location for
-    class name [class_name] *)
diff --git a/infer/src/java/jSourceFileInfo.mll b/infer/src/java/jSourceFileInfo.mll
new file mode 100644
index 000000000..16f1146e6
--- /dev/null
+++ b/infer/src/java/jSourceFileInfo.mll
@@ -0,0 +1,401 @@
+(*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *)
+
+{
+  open! IStd
+
+  open Lexing
+
+  module Array = struct
+    include Array
+    let make len = create ~len
+  end
+
+  (** classic Ocamllex function to update current lexbuf line at each end of
+     line *)
+  let incr_linenum lexbuf =
+    let pos = lexbuf.Lexing.lex_curr_p in
+    lexbuf.Lexing.lex_curr_p <- { pos with
+      Lexing.pos_lnum = pos.Lexing.pos_lnum + 1;
+      Lexing.pos_bol = pos.Lexing.pos_cnum;
+    }
+
+  (** position of the char just after lexbuf *)
+  let end_pos lexbuf =
+    lexbuf.lex_curr_p.pos_lnum,
+    lexbuf.lex_curr_p.pos_cnum - lexbuf.lex_curr_p.pos_bol
+
+  (** return the exact position start of the suffix [classname] in [lexbuf] *)
+  let location_suffix suffix lexbuf =
+    let length_suffix = String.length suffix in
+    let l, c = end_pos lexbuf in
+    l, c - length_suffix
+
+  (** return the position start of [lexbuf] *)
+  let location_start lexbuf =
+    let l, c = end_pos lexbuf in
+    let lexbuf_length = lexeme_end lexbuf - lexeme_start lexbuf in
+    l, c - lexbuf_length
+
+  (** We traverse the structure of the source file by recording the
+      encompassing blocks in a stack of frame.
+      We use the stack to recover the full inner class name at bytecode level *)
+  type expr = | AllocExpr | OtherExpr
+  type frame =
+    { short_class_name: string
+    ; is_enum : bool
+    ; next_anonymous_class: int
+    ; opened_blocks: int
+    ; exprs: expr list }
+  type state =
+    { stack: frame list
+    ; record_location: classname:string -> col:int -> line:int -> unit }
+
+  let push frame state = { state with stack = frame :: state.stack; }
+
+  exception Missing_opening_bracket
+
+  exception Missing_opening_parenthesis
+
+  let add_package package state =
+    let record_location ~classname =
+      let classname = package^"."^classname in
+      state.record_location ~classname in
+    { state with record_location; }
+
+  let pop_class state =
+    match state.stack with
+     | [] -> raise Missing_opening_bracket
+     | _ :: stack -> { state with stack; }
+
+  let incr_next_anonymous state =
+    match state.stack with
+    | [] -> { state with stack = []; }
+    | fr :: stack ->
+        let stack =
+         {fr with next_anonymous_class = fr.next_anonymous_class+1; } :: stack in
+        { state with stack; }
+
+  let add_expr e (state:state) : state =
+    match state.stack with
+    | [] -> state
+    | fr :: stack ->
+        let stack = {fr with exprs = e :: fr.exprs; } :: stack in
+        { state with stack; }
+
+  let pop_exprs state =
+    match state.stack with
+    | [] -> raise Missing_opening_parenthesis
+    | fr :: stack -> (
+        match fr.exprs with
+          | [] -> raise Missing_opening_parenthesis
+          | e :: exprs ->
+            let stack = {fr with exprs; } :: stack in
+            (e, { state with stack; }))
+
+  let in_field_declaration_area state =
+    match state.stack with
+     | [] -> false
+     | fr :: _ -> Int.equal fr.opened_blocks 0
+
+  let get_opened_blocks state =
+    match state.stack with
+    | [] -> raise Missing_opening_bracket
+    | fr :: _ -> fr.opened_blocks
+
+  let is_enum state =
+    match state.stack with
+    | [] -> false
+    | fr :: _ -> fr.is_enum && Int.equal fr.opened_blocks 0
+
+  let get_next_anonymous_class state =
+    match state.stack with
+    | [] -> raise Missing_opening_bracket
+    | fr :: _ -> string_of_int fr.next_anonymous_class
+
+  let decr_opened_blocks state =
+    let stack =
+      match state.stack with
+      | [] -> []
+      | fr :: stack ->
+          {fr with opened_blocks = fr.opened_blocks-1; } :: stack in
+     { state with stack; }
+
+  let incr_opened_blocks state =
+    let stack =
+      match state.stack with
+      | [] -> []
+      | fr :: stack ->
+          {fr with opened_blocks = fr.opened_blocks+1; } :: stack in
+     { state with stack; }
+
+  let long_class_name name state =
+    let f name frame = Printf.sprintf "%s$%s" frame.short_class_name name in
+    List.fold ~f ~init:name state.stack
+
+}
+
+let whitespace = [' ' '\t']
+let eol = whitespace*("\r")?"\n" (* end of line *)
+let eol_comment = "//" [^'\n']*
+let id = ['a'-'z' 'A'-'Z' '_' '$'] ['a'-'z' 'A'-'Z' '0'-'9' '_' '$']*
+let char = "'\\''" | "'\"'" | "'" [ ^'\'' ]+ "'"
+let class_keyword = "class"|"interface"|"enum"|"@" whitespace+ "interface"
+
+(* We follow an abstraction of the official grammar described here:
+    https://docs.oracle.com/javase/specs/jls/se14/html/jls-19.html *)
+rule class_scan state = parse
+  | whitespace+
+        { class_scan state lexbuf }
+  | eol_comment
+        { class_scan state lexbuf }
+  | "/*"
+        { skip_comments (class_scan state) lexbuf }
+  | eol
+        { incr_linenum lexbuf;
+          class_scan state lexbuf }
+  | "package" whitespace+ (id ("." id)* as package) whitespace* ";"
+        { class_scan (add_package package state) lexbuf }
+  | id
+        { class_scan state lexbuf }
+  | class_keyword whitespace+ (id as name)
+        {
+          let line, col = location_suffix name lexbuf in
+          let classname = long_class_name name state in
+          state.record_location ~classname ~col ~line ;
+          let frame : frame =
+            { short_class_name = name;
+              is_enum = false;
+              next_anonymous_class = 1;
+              exprs = [];
+              opened_blocks = 0 } in
+          (* we jump to the next left bracket, skipping annotations and
+             generics <...> contents *)
+          do_at_next_left_bracket
+            (fun lexbuf ->
+              class_scan (push frame state) lexbuf) lexbuf
+        }
+  | "new" whitespace+
+        { (* may be a declaration of an anonymous class
+             ```new [TypeArguments] ClassOrInterfaceTypeToInstantiate
+                    ( [ArgumentList] ) [ClassBody] ```
+                                      ^
+             so we jump this position |                  *)
+          search_anonymous_class_body state lexbuf
+        }
+  | id
+        { if is_enum state
+          then found_entrance_of_anonymous_class state lexbuf
+          else class_scan state lexbuf }
+  | (id as _field) whitespace* ";"
+        { if in_field_declaration_area state then
+            (* we only reach this situation in class/interface bodies, and
+               never inside method bodies *)
+             () ; (* TODO : record field location *)
+          class_scan state lexbuf
+        }
+  | "\""
+        { skip_string (class_scan state) lexbuf }
+  | char
+        { class_scan state lexbuf }
+  | "{"
+        { class_scan (incr_opened_blocks state) lexbuf }
+  | "("
+        { class_scan (add_expr OtherExpr state) lexbuf }
+  | ")"
+        { match pop_exprs state with
+            | AllocExpr, state -> found_entrance_of_anonymous_class state lexbuf
+            | OtherExpr, state -> class_scan state lexbuf }
+  | "@" whitespace* id ("." id)* "("
+        { skip_well_parenthesized_parentheses 1
+            (class_scan state) lexbuf }
+  | "}"
+        {
+          if Int.equal (get_opened_blocks state) 0
+          then class_scan (pop_class state) lexbuf
+          else class_scan (decr_opened_blocks state) lexbuf
+        }
+  | _
+        { class_scan state lexbuf }
+  | eof
+        { () }
+
+(* we search for the next left bracket *)
+and do_at_next_left_bracket action = parse
+  | eol
+        { incr_linenum lexbuf;
+          do_at_next_left_bracket action lexbuf }
+  | eol_comment
+        { do_at_next_left_bracket action lexbuf }
+  | "/*"
+        { skip_comments (do_at_next_left_bracket action) lexbuf }
+  | "{"
+        { action lexbuf }
+  | "<"
+        { skip_well_parenthesized_angles 1
+             (do_at_next_left_bracket action) lexbuf }
+  | "@" whitespace* id "("
+        { skip_well_parenthesized_parentheses 1
+            (do_at_next_left_bracket action) lexbuf }
+  | "\""
+        { skip_string (do_at_next_left_bracket action) lexbuf }
+  | _
+        { do_at_next_left_bracket action lexbuf }
+
+(* we search for (...) parentheses *)
+and search_anonymous_class_body state = parse
+  | eol
+        { incr_linenum lexbuf;
+          search_anonymous_class_body state lexbuf }
+  | eol_comment
+        { search_anonymous_class_body state lexbuf }
+  | "/*"
+        { skip_comments
+            (search_anonymous_class_body state) lexbuf }
+  | "("
+        { class_scan (add_expr AllocExpr state) lexbuf }
+  | "<"
+        { skip_well_parenthesized_angles 1
+             (search_anonymous_class_body state) lexbuf }
+  | "@" whitespace* id "("
+        { skip_well_parenthesized_parentheses 1
+             (search_anonymous_class_body state) lexbuf }
+  | "\""
+        { skip_string
+             (search_anonymous_class_body state) lexbuf }
+  | "["
+        { (* this is an array allocation, not an anonymous class *)
+          class_scan state lexbuf
+        }
+  | _
+        { search_anonymous_class_body state lexbuf }
+
+(* we test if there is an opening anonymous class body here *)
+and found_entrance_of_anonymous_class state = parse
+  | eol
+        { incr_linenum lexbuf;
+          found_entrance_of_anonymous_class state lexbuf }
+  | eol_comment
+        { found_entrance_of_anonymous_class state lexbuf }
+  | "/*"
+        { skip_comments
+            (found_entrance_of_anonymous_class state) lexbuf }
+  | whitespace+
+        { found_entrance_of_anonymous_class state lexbuf }
+  | "{"
+        { (* this is an anonymous class *)
+          let line, col = location_start lexbuf in
+          let name = get_next_anonymous_class state in
+          let classname = long_class_name name state in
+          state.record_location ~classname ~col ~line ;
+          let frame : frame =
+            { short_class_name = name;
+              is_enum = false;
+              next_anonymous_class = 1;
+              exprs = [];
+              opened_blocks = 0 } in
+          class_scan (push frame (incr_next_anonymous state)) lexbuf
+        }
+  | _
+        { (* this is not an anonymous class *)
+          class_scan state lexbuf
+        }
+
+(* we skip type arguments <...> because they may contain brackets *)
+and skip_well_parenthesized_angles width action = parse
+  | eol
+        { incr_linenum lexbuf;
+           skip_well_parenthesized_angles width action lexbuf }
+  | "<"
+        { skip_well_parenthesized_angles (width+1) action lexbuf }
+  | ">"
+        { if width <= 1 then action lexbuf
+          else skip_well_parenthesized_angles (width-1) action lexbuf }
+  | eol_comment
+        { skip_well_parenthesized_angles width action lexbuf }
+  | "/*"
+        { skip_comments
+             (skip_well_parenthesized_angles width action) lexbuf }
+  | "\""
+        { skip_string (skip_well_parenthesized_angles width action) lexbuf }
+  | _
+        { skip_well_parenthesized_angles width action lexbuf }
+
+(* we skip type annotation arguments (...) because they may contain brackets *)
+and skip_well_parenthesized_parentheses width action = parse
+  | eol
+        { incr_linenum lexbuf;
+           skip_well_parenthesized_parentheses width action lexbuf }
+  | "("
+        { skip_well_parenthesized_parentheses (width+1) action lexbuf }
+  | ")"
+        { if width <= 1 then action lexbuf
+          else skip_well_parenthesized_parentheses (width-1) action lexbuf }
+  | eol_comment
+        { skip_well_parenthesized_parentheses width action lexbuf }
+  | "/*"
+        { skip_comments
+             (skip_well_parenthesized_parentheses width action) lexbuf }
+  | "\""
+        { skip_string (skip_well_parenthesized_parentheses width action) lexbuf }
+  | char
+        { skip_well_parenthesized_parentheses width action lexbuf }
+  | _
+        { skip_well_parenthesized_parentheses width action lexbuf }
+
+and skip_string action = parse
+  | "\\\\"
+        { skip_string action lexbuf }
+  | "\\\""
+        { skip_string action lexbuf }
+  | "\""
+        { action lexbuf }
+  | _
+        { skip_string action lexbuf }
+
+and skip_comments action = parse
+  | "*/"
+        { action lexbuf }
+  | eol
+        { incr_linenum lexbuf;
+          skip_comments action lexbuf }
+  | _
+        { skip_comments action lexbuf }
+
+{
+
+  open Javalib_pack
+
+  (** We scan source file [file] and record location of each class declaration *)
+  let collect_class_location (program:JClasspath.program) (file:SourceFile.t) =
+    let cin = In_channel.create (SourceFile.to_abs_path file) in
+    let stack = [] in
+    let record_location ~classname ~col ~line =
+      let loc : Location.t =  { line; col; file } in
+      let cn : JBasics.class_name = JBasics.make_cn classname in
+      Logging.debug Capture Verbose "set_java_location %s with location %a@."
+        (JBasics.cn_name cn) Location.pp_file_pos loc;
+      JClasspath.set_java_location program cn loc in
+    try (
+      class_scan { record_location; stack; } (from_channel cin) ;
+      In_channel.close cin )
+    with
+      | Failure s ->
+        raise
+          (Failure
+            (Printf.sprintf "Error parsing source file %s\n%s" (SourceFile.to_abs_path file) s))
+      | Missing_opening_bracket ->
+        raise
+           (Failure (Printf.sprintf "Missing opening bracket error while parsing source file %s\n"
+                       (SourceFile.to_abs_path file)))
+      | Missing_opening_parenthesis ->
+        raise
+           (Failure
+             (Printf.sprintf "Missing opening parenthesis error while parsing source file %s\n"
+                (SourceFile.to_abs_path file)))
+
+}