Currently, the java printer is not able to break a variable declaration into two lines such as:

private static int some_variable = 
    some_random_value;

I've tried to use a few tricks to make it doable but I can't seem to be able to handle the priority of grouping.

// Should be
private static int some_variable = some_random_function(
    value1,
    value2
);

// This breaks the line when we are using a binary operator instead of breaking the argument list.
private static int some_variable =
    some_random_function(value1, value2) + "literal_value";

// What it does no matter what
private static int some_variable =
    some_random_function(value1, value2);

This suits PrettierJS in this specific case but overrides many other cases (see 2nd example)

The issue is that you cannot tell which group should break in priority with the prettier API : see https://github.com/prettier/prettier/blob/master/commands.md#group

Groups are usually nested, and the printer will try to fit everything on one line, but if it doesn't fit it will break the outermost group first and try again. It will continue breaking groups until everything fits (or there are no more groups to break).

Indeed it looks like the outermost will always break in priority.
In our case it seems to vary, sometimes the innermost breaks first...

I am closing this PR as this is currently too difficult. I will rework on this at a later date with smaller PR's because this one is dependent of others