Java

1. Install Eclipse JDT Language Server
2. Create executable jdtls in path, with content:

   java \
       -Declipse.application=org.eclipse.jdt.ls.core.id1 \
       -Dosgi.bundles.defaultStartLevel=4 \
       -Declipse.product=org.eclipse.jdt.ls.core.product \
       -noverify \
       -Xms1G \
       -jar {{ your java lsp installation }}/eclipse.jdt.ls/org.eclipse.jdt.ls.product/target/repository/plugins/org.eclipse.equinox.launcher_1.5.0.v20180207-1446.jar \
       -configuration {{ your java lsp installation }}/eclipse.jdt.ls/org.eclipse.jdt.ls.product/target/repository/config_linux/ \
       "$@"
   

3. Add to your vim config:

   let g:LanguageClient_serverCommands = {
       \ 'java': ['jdtls', '-Dlog.level=ALL'],
       \ }
   

All folders should be absolute.