asyncJsWaitsJava.js

async function() {
  // a Java object implementing the `then` method
  let javaTrampoline = ... // created from Java
  // create a JavaScript promise
  let interopPromise = new Promise(javaTrampoline);
  // register some promise reactions
  try {
    // await for the “interop” promise to resolve
    let result = await interopPromise;
    console.log('Java resolves: ' + result);
  } catch (error) {
    // handle project rejection
    console.log('Java rejects: ' + error);
  }
}