[FEATURE REQUEST] nvim-java support as alternative to nvim-jdtls

[eruizc-dev]

What the title says,

Are there any intentions of supporting nvim-java as an alternative to nvim-jdtls?

[rcasia]

Thank you for opening this issue. Until now, support for nvim-java had not been considered.

As nvim-java uses jdtls underneath, we can bring support by avoiding direct calls to nvim-jdtls and relying solely on the vim.lsp.Client API for this tasks:

• Triggering a compilation for the project source code.
• Retrieving the project's classpaths.
• Retrieving the JAVA_HOME chosen by the LSP.

Refactor example in 0ca4f0f.