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/ \
    "$@"

1. Add to your vim config:

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

Before starting the lsp, your cwd should be set to the directory of your pom, not the file you are editing.

This sets the cwd to the directory of the in your window:

nnoremap <leader>cd :cd %:p:h<CR>:pwd<CR>