Test.java

class TestInt extends Test {
    private int i;
    public TestInt(int i) { this.i = i; }
    public String foo() {
        if (i == 1) return "bar";
        return super.foo();
    }
}

class TestStr extends Test {
    private String s;
    public TestStr(String s) { this.s = s; }
    public String foo() {
        if (s.equals("1")) return "baz";
        return super.foo();
    }
}

abstract class Test {
    public String foo() { return "?"; }
    public static void main(String[] args) {
        System.out.println(new TestInt( 0 ).foo());
        System.out.println(new TestInt( 1 ).foo());
        System.out.println(new TestStr("0").foo());
        System.out.println(new TestStr("1").foo());
    }
}

Test.scala

class TestInt(i :Int) extends Test {
    override def foo(): String = {
        if (i == 1) return "bar"
        super.foo()
    }
}

class TestStr(s :String) extends Test {
    override def foo(): String = {
        if (s.equals("1")) return "baz"
        super.foo()
    }
}

class Test {
    def foo() = "?"
}

object Test {
  def main(args: Array[String]) {
    println(new TestInt( 0 ).foo());
    println(new TestInt( 1 ).foo());
    println(new TestStr("0").foo());
    println(new TestStr("1").foo());
  }
}