Eclipse Mars: Content Assistant doesn't complete when pressing dot

Question

When I type in the first part of a local variable name and press Ctrl+Space in order to show up the content assistant, then it displays the full name of the variable and preselects it.

In Eclipse Luna release the full name becomes inserted if you press . on keyboard and the content assistant shows up all accessible members of this variable instance.

With Eclipse Mars it inserts the dot directly after the incomplete variable name.

How can I switch this behavior back to Eclipse Luna?

public class A {
    public int member;

    public void possiblyAll(){

    }
}

public class Test {
    private A aMemberNameWhichIsLong_1;

    private A aMemberNameWhichIsLong_2;

    private A aMemberNameWhichIsLong_3;

    public static void main(String[] args) {
        Test t = new Test();
        t.amem
    }
}

In this example, the caret is located after t.amem. Ctrl+Space displays the full name. Pressing . closes content assistant and produces this code: t.amem.

In Luna it was: t.aMemberNameWhichIsLong_1.

Answer 1

This was a bug introduced by the Code Recommenders plug-in (see answer by @Johannes Dorn for the fix).

You can (temporarily) disable Code Recommenders via Window > Preferences > Code Recommenders > Completions > [x] Enable Code Recommenders code completion