a.md

https://curelemonade2.hatenablog.com/entry/2021/03/12/180354

A.scala

class A {
  println("scala 1 " + s)
  val s = "hello"
  println("scala 2 " + s)
}

B.java

public class B {
  {
    System.out.println("java 1 " + s());
  }

  private String s0 = "hello";
  public String s() {
    return s0;
  }

  {
    System.out.println("java 2 " + s());
  }
}

log

[info] running Main 
scala 1 null
scala 2 hello
java 1 null
java 2 hello

Main.scala

object Main {
  def main(args: Array[String]): Unit = {
    new A
    new B
  }
}