Better infer extracted method name based on context

[fbricon]

When refactoring > extract to a method..., the default method name is extracted. In similar situations, Intellij IDEA is smarter and can propose a method name based on context.

In this exemple:

var parts = new String[]{"Hello", "Java", "16"};

// start selecting line from below
var greeting = new StringBuilder();
for(int i = 0; i < parts.length; i++) {
    var part = parts[i];
    if (i >0) {
        greeting.append(" ");
    }
    greeting.append(part);
}
// end selection including previous closing bracket
System.out.println(greeting);

In vscode-java, extraction will create:

var greeting = extracted(parts);

in IntelliJ, you'll get the choice between getStringBuilder, getBuilder, getGreeting by default.

I don't think we can propose several names in vscode-java, but it'd be nice to, at least in that case, propose getGreeting by default.

cc @maxandersen

[fbricon]

Found upstream bug opened by @maxandersen : https://bugs.eclipse.org/bugs/show_bug.cgi?id=570785

[rgrunber]

@JessicaJHee , I started something with rgrunber/eclipse.jdt.ls@cc7273d . If it makes sense, you should make a PR with that and then add tests / react in ExtractMethodTest .