nvim-java · olisikh · May 20, 2026 · Jun 8, 2026 · s1n7ax · Jun 7, 2026
diff --git a/lua/java.lua b/lua/java.lua
@@ -79,6 +79,10 @@ function M.setup(custom_config)
 	----------------------------------------------------------------------
 	--                               init                               --
 	----------------------------------------------------------------------
+	if config.experimental.fix_generated_sources then
+		require('java.experimental.fix-generated-sources').patch(vim.fn.getcwd())
+	end
+
 	require('java.startup.lsp_setup').setup(config)
 	require('java.startup.decompile-watcher').setup()
 	require('java-refactor').setup()

diff --git a/lua/java/config.lua b/lua/java/config.lua
@@ -27,6 +27,7 @@ local V = jdtls_version_map[JDTLS_VERSION]
 ---@field java_debug_adapter { enable: boolean, version: string }
 ---@field spring_boot_tools { enable: boolean, version: string }
 ---@field jdk { auto_install: boolean, version: string }
+---@field experimental { fix_generated_sources: boolean }
 ---@field log java-core.Log2Config
 
 ---@class java.PartialConfig
@@ -37,6 +38,7 @@ local V = jdtls_version_map[JDTLS_VERSION]
 ---@field java_debug_adapter? { enable?: boolean, version?: string }
 ---@field spring_boot_tools? { enable?: boolean, version?: string }
 ---@field jdk? { auto_install?: boolean, version?: string }
+---@field experimental? { fix_generated_sources?: boolean }
 ---@field log? java-core.PartialLog2Config
 
 ---@type java.Config
@@ -46,6 +48,10 @@ local config = {
 		nvim_jdtls_conflict = true,
 	},
 
+	experimental = {
+		fix_generated_sources = false,
+	},
+
 	jdtls = {
 		version = JDTLS_VERSION,
 	},

diff --git a/lua/java/experimental/fix-generated-sources.lua b/lua/java/experimental/fix-generated-sources.lua
@@ -0,0 +1,252 @@
+local path_utils = require('java-core.utils.path')
+local log = require('java-core.utils.log2')
+
+local M = {}
+
+---Normalize path separators to `/` for .classpath operations.
+---Eclipse .classpath files always use `/` regardless of OS.
+---@param p string
+---@return string
+local function classpath_normalize(p)
+	return p:gsub('\\', '/')
+end
+
+---Set or update the `excluding` attribute on a classpathentry line.
+---Parses any existing exclusions, merges with the new set (union),
+---and writes the sorted result back.
+---@param line string
+---@param exclusions string[]
+---@return string
+local function set_exclusions(line, exclusions)
+	-- Parse existing exclusions from the line
+	local existing = {}
+	local existing_match = line:match('excluding="([^"]+)"')
+	if existing_match then
+		for entry in existing_match:gmatch('[^|]+') do
+			existing[entry] = true
+		end
+	end
+
+	-- Merge: union existing + new (new keys take no precedence — it's a set union)
+	local merged = vim.deepcopy(existing)
+	for _, excl in ipairs(exclusions) do
+		merged[excl] = true
+	end
+
+	local merged_list = vim.tbl_keys(merged)
+	table.sort(merged_list)
+	local exclusion_value = table.concat(merged_list, '|')
+
+	if existing_match then
+		return line:gsub('excluding="[^"]+"', 'excluding="' .. exclusion_value .. '"', 1)
+	end
+
+	return line:gsub('<classpathentry ', '<classpathentry excluding="' .. exclusion_value .. '" ', 1)
+end
+
+---Get the relative path from root. Result is normalized to `/`
+---for .classpath compatibility.
+---@param root string
+---@param absolute_path string
+---@return string
+local function get_relative_path(root, absolute_path)
+	local prefix = root .. path_utils.path_separator
+	local relative
+	if absolute_path:sub(1, #prefix) == prefix then
+		relative = absolute_path:sub(#prefix + 1)
+	else
+		relative = absolute_path
+	end
+	return classpath_normalize(relative)
+end
+
+---@param lines string[]
+---@param entry_path string
+---@return boolean
+local function has_classpath_entry(lines, entry_path)
+	local pattern = 'path="' .. entry_path .. '"'
+	for _, line in ipairs(lines) do
+		if line:find(pattern, 1, true) then
+			return true
+		end
+	end
+	return false
+end
+
+---Find the index of the target/generated-sources classpathentry.
+---Assumes .classpath uses double or single quotes and one tag per line.
+---@param lines string[]
+---@return integer|nil
+local function find_generated_sources_entry(lines)
+	for index, line in ipairs(lines) do
+		if
+			line:find('path="target/generated%-sources"')
+			or line:find("path='target/generated%-sources'")
+		then
+			return index
+		end
+	end
+	return nil
+end
+
+---Insert a new classpathentry before the <classpathentry kind="output"> line.
+---@param lines string[]
+---@param entry_path string
+local function add_classpath_entry(lines, entry_path)
+	local entry = {
+		'\t<classpathentry kind="src" output="target/classes" path="' .. entry_path .. '">',
+		'\t\t<attributes>',
+		'\t\t\t<attribute name="optional" value="true"/>',
+		'\t\t\t<attribute name="maven.pomderived" value="true"/>',
+		'\t\t</attributes>',
+		'\t</classpathentry>',
+	}
+
+	local output_index = #lines + 1
+	for index, line in ipairs(lines) do
+		if line:find('<classpathentry kind="output"') then
+			output_index = index
+			break
+		end
+	end
+
+	for offset = #entry, 1, -1 do
+		table.insert(lines, output_index, entry[offset])
+	end
+end
+
+---Find generated source roots under target/generated-sources that
+---match the pattern `*/src/{segment}/java`.
+---@param module_root string
+---@return string[]
+local function get_generated_source_roots(module_root)
+	local generated_root = path_utils.join(module_root, 'target', 'generated-sources')
+	if not vim.uv.fs_stat(generated_root) then
+		return {}
+	end
+
+	-- Match 'target/generated-sources' substring using OS-native path separators
+	local target_gen_src = path_utils.join('target', 'generated-sources')
+	local java_roots = vim.fs.find(function(name, generated_path)
+		return name == 'java' and generated_path:find(target_gen_src, 1, true) ~= nil
+	end, {
+		path = generated_root,
+		type = 'directory',
+		limit = 500,
+	})
+
+	local source_roots = {}
+	local seen_roots = {}
+	for _, java_root in ipairs(java_roots) do
+		local relative_to_generated_root = get_relative_path(generated_root, java_root)
+		-- Split on / since get_relative_path normalizes
+		local segments = vim.split(relative_to_generated_root, '/', { plain = true })
+		local segment_count = #segments
+
+		if segment_count >= 3 and segments[segment_count] == 'java' and segments[segment_count - 2] == 'src' then
+			local source_root = get_relative_path(module_root, java_root)
+			if not seen_roots[source_root] then
+				seen_roots[source_root] = true
+				table.insert(source_roots, source_root)
+			end
+		end
+	end
+
+	table.sort(source_roots)
+	return source_roots
+end
+
+---Build exclusion list for the parent target/generated-sources entry.
+---Always seeds `annotations/` — Eclipse/Maven convention excludes the
+---annotations subdirectory from generated-sources to avoid processing
+---compiled annotation processor output as source.
+---@param source_roots string[]
+---@return string[]
+local function get_generated_source_exclusions(source_roots)
+	local exclusions = { ['annotations/'] = true }
+	-- Normalize prefix to / for comparison with source_roots (which are /-normalized)
+	local generated_root_prefix = classpath_normalize(path_utils.join('target', 'generated-sources')) .. '/'
+
+	for _, source_root in ipairs(source_roots) do
+		if source_root:sub(1, #generated_root_prefix) == generated_root_prefix then
+			local relative_to_generated_root = source_root:sub(#generated_root_prefix + 1)
+			local first_segment = vim.split(relative_to_generated_root, '/', { plain = true })[1]
+			if first_segment then
+				exclusions[first_segment .. '/'] = true
+			end
+		end
+	end
+
+	local ordered_exclusions = vim.tbl_keys(exclusions)
+	table.sort(ordered_exclusions)
+	return ordered_exclusions
+end
+
+---Patch a single .classpath file to include generated source roots
+---and exclude them from the parent generated-sources entry.
+---Safe to re-run — idempotent (has_classpath_entry + set_exclusions
+---no-op when already applied).
+---@param classpath_file string
+---@return boolean changed
+local function patch_module_classpath(classpath_file)
+	local module_root = vim.fs.dirname(classpath_file)
+	local lines = vim.fn.readfile(classpath_file)
+	local generated_sources_entry_index = find_generated_sources_entry(lines)
+	if not generated_sources_entry_index then
+		return false
+	end
+
+	local file_changed = false
+	local source_roots = get_generated_source_roots(module_root)
+	local line = lines[generated_sources_entry_index]
+	local patched = set_exclusions(line, get_generated_source_exclusions(source_roots))
+
+	if patched ~= line then
+		lines[generated_sources_entry_index] = patched
+		file_changed = true
+	end
+
+	for _, source_root in ipairs(source_roots) do
+		if not has_classpath_entry(lines, source_root) then
+			add_classpath_entry(lines, source_root)
+			file_changed = true
+		end
+	end
+
+	if file_changed then
+		log.info('nvim-java: patching .classpath with generated sources', classpath_file)
+		vim.fn.writefile(lines, classpath_file)
+	end
+
+	return file_changed
+end
+
+---Patch all .classpath files under `root` to include generated source roots.
+---This is an experimental workaround for JDTLS import failures caused by
+---nested generated sources under target/generated-sources.
+---@param root string # Project root directory
+---@return boolean changed # true if any .classpath file was modified
+function M.patch(root)
+	local changed = false
+	local start = vim.uv.hrtime()
+	local count = 0
+	local LIMIT = 500
+
+	for _, file in ipairs(vim.fs.find('.classpath', { path = root, type = 'file', limit = LIMIT })) do
+		if patch_module_classpath(file) then
+			changed = true
+		end
+		count = count + 1
+	end
+
+	if count >= LIMIT then
+		log.warn('nvim-java: fix_generated_sources hit .classpath find limit (' .. LIMIT .. ') — some files may be missed')
+	end
+
+	local elapsed = (vim.uv.hrtime() - start) / 1e6
+	log.debug(('nvim-java: fix_generated_sources scanned %d .classpath files in %.2fms'):format(count, elapsed))
+
+	return changed
+end
+
+return M