Send messages for jdt files

JDT files are essentially Java source files. By sending messages for jdt
files, we are able to use language server functionalities in those
files, such as go to definition or type definition which is supper
helpful for browsing source code.

Author: cheuk-fung

autoload/LanguageClient.vim

@@ -644,8 +644,16 @@ function! LanguageClient#Write(message) abort
     endif
 endfunction
 
+function! s:SkipSendingMessage() abort
+    if expand('%') =~# '^jdt://'
+        return v:false
+    endif
+
+    return &buftype !=# '' || &filetype ==# '' || expand('%') ==# ''
+endfunction
+
 function! LanguageClient#Call(method, params, callback, ...) abort
-    if &buftype !=# '' || &filetype ==# '' || expand('%') ==# ''
+    if s:SkipSendingMessage()
         " call s:Debug('Skip sending message')
         return
     endif
@@ -675,7 +683,7 @@ function! LanguageClient#Call(method, params, callback, ...) abort
 endfunction
 
 function! LanguageClient#Notify(method, params) abort
-    if &buftype !=# '' || &filetype ==# '' || expand('%') ==# ''
+    if s:SkipSendingMessage()
         " call s:Debug('Skip sending message')
         return
     endif